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MD Dermatology — 3rd Year PG Theory Examination

10-Mark Answer Bank

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A. ALOPECIA MUCINOSA (Follicular Mucinosis)

Definition

Classification

Etiopathogenesis

• Exact etiology unknown; possible immune-mediated T-cell reaction
• In secondary type: neoplastic T-cells in CTCL produce mucin-stimulating cytokines (IL-4, IL-13) → glycosaminoglycan (hyaluronic acid) accumulation in follicular epithelium
• Borrelia burgdorferi association reported in some cases

Clinical Features

• Primary type: Grouped follicular papules/plaques on face, scalp, and neck; associated alopecia; pruritus; self-resolves in 2 years
• Secondary type (CTCL-associated): Older patients; widespread lesions; associated with patches/plaques of MF; may have peripheral lymphadenopathy
• Key feature: follicular prominence, "orange peel" texture, alopecia in plaques

Investigations

• Histopathology (gold standard):
  • Mucin accumulation in outer root sheath and sebaceous glands
  • Alcian blue (pH 2.5) and colloidal iron stain: positive for acid mucopolysaccharides
  • Lymphocytic infiltrate in follicular epithelium (eosinophilic in primary; atypical lymphocytes in secondary)
• T-cell receptor gene rearrangement: positive in CTCL-associated type
• Serology: Borrelia serology if clinically indicated
• Staging workup if CTCL suspected: LDH, peripheral blood smear, imaging

Treatment

• Primary: Spontaneous resolution in 2 months–2 years
  • Topical/intralesional corticosteroids
  • Dapsone 100 mg/day
  • Hydroxychloroquine 200–400 mg/day
  • PUVA, doxycycline (anti-inflammatory)
• Secondary/CTCL: Treat underlying MF — PUVA, retinoids, interferon-alpha, chemotherapy

Prognosis

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B. EXTRAMAMMARY PAGET'S DISEASE (EMPD)

Definition

Etiopathogenesis

1. Primary EMPD (80%): In-situ adenocarcinoma arising from pluripotent stem cells or intraepidermal Toker cells/apocrine duct cells
2. Secondary EMPD (20%): Epidermotropic spread from underlying internal malignancy (colorectal, bladder, cervical carcinoma)

• Associated internal malignancies in ~35% of EMPD cases

Clinical Features

• Site: Vulva (most common in women), perineum, perianal, scrotum (men), axilla
• Appearance: Well-demarcated, erythematous, eczematous or lichenified plaque; may have crusting, erosions, white scaling
• Classic description: "Non-healing anogenital eczema" — key exam phrase
• Symptoms: pruritus, burning, pain; often misdiagnosed as eczema/fungal infection for years
• Invasive EMPD: may develop nodules/ulceration

Investigations

• Biopsy/Histopathology:
  • Large pale vacuolated "Paget cells" (intraepidermal, mucin-containing) with prominent nucleoli
  • Cells arranged singly, in nests, or glandular patterns
  • PAS-positive, diastase-resistant mucin
• Immunohistochemistry:
  • Primary EMPD: CK7+, CK20−, GCDFP-15+, CEA+
  • Secondary (colorectal origin): CK7+, CK20+, CDX2+
  • Uroplakin III+ if bladder origin
• Colonoscopy, cystoscopy, CT abdomen/pelvis to exclude internal malignancy

Treatment

• Gold standard: Mohs micrographic surgery (MMS) — best margin control
• Wide local excision with 2–3 cm margins (high recurrence rate 30–60%)
• Topical imiquimod 5% cream: useful for extensive/inoperable cases
• Photodynamic therapy (PDT)
• Radiation therapy for inoperable cases
• Secondary EMPD: treat primary malignancy

Prognosis

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C. SUBACUTE CUTANEOUS LUPUS ERYTHEMATOSUS (SCLE)

Definition

Etiopathogenesis

• Autoantibodies: Anti-Ro/SSA: 70–100%; Anti-La/SSB: 30–40%
• HLA association: HLA-DR3, HLA-B8 (strongest HLA association in LE)
• UV radiation → Ro/SSA antigen expression on keratinocyte surface → antibody-mediated and T-cell cytotoxicity → interface dermatitis
• Drug-induced SCLE: Terbinafine (#1 cause), hydrochlorothiazide, CCBs, PPIs, TNF-α inhibitors, chemotherapy agents

Clinical Features

1. Papulosquamous (psoriasiform) type (50%): Scaly papules/plaques resembling psoriasis or seborrheic dermatitis
2. Annular/polycyclic type (50%): Annular lesions with central clearing and fine scaling at periphery

Investigations

• ANA: Positive in 60–80% (low titer, speckled pattern)
• Anti-Ro/SSA: 70–100% (hallmark); Anti-La/SSB: 30–40%
• Histopathology: Interface dermatitis (vacuolar type), superficial perivascular lymphocytic infiltrate, epidermal atrophy, melanin incontinence; NO follicular plugging; NO scarring
• DIF: Lupus band (IgG, IgM, C3 at DEJ) in ~60%; less reliable than in DLE
• CBC, urinalysis, complement levels, anti-dsDNA to assess systemic involvement

Treatment

1. Photoprotection: Strict sun avoidance, broad-spectrum SPF ≥50 — cornerstone
2. Topical: Corticosteroids, tacrolimus/pimecrolimus
3. Antimalarials: Hydroxychloroquine 200–400 mg/day (first-line systemic) ± quinacrine
4. Second-line: Dapsone, thalidomide, retinoids (acitretin)
5. Refractory: Methotrexate, mycophenolate mofetil, belimumab
6. Drug-induced SCLE: Withdraw offending drug; may resolve in weeks–months

Prognosis

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D. DRESS SYNDROME (Drug Reaction with Eosinophilia and Systemic Symptoms)

Definition

Also known as:

Etiopathogenesis

• Mechanism: Sequential reactivation of herpesviruses:
  • HHV-6 reactivation (most consistent, ~70%)
  • Also HHV-7, EBV, CMV
• HLA associations: HLA-B*58:01 (allopurinol in Han Chinese, Thai); HLA-B*57:01 (abacavir); HLA-A*31:01 (carbamazepine in Europeans)
• Pharmacogenomics: Slow acetylators at higher risk with sulfonamides, dapsone

• Sulfonamides
• Allopurinol (#1 overall), Anticonvulsants (carbamazepine, phenytoin, phenobarbital, lamotrigine)
• Vancomycin
• Efective antiepileptics (valproate)
• Dapsone, minocycline, abacavir, nevirapine

Clinical Features

• Onset: 2–8 weeks (long latency — key differentiator from other drug reactions)
• Skin (95%): Morbilliform exanthem starting on face/upper trunk spreading downward; facial edema (hallmark — periorbital puffiness); may progress to exfoliative erythroderma
• Lymphadenopathy: Generalized, tender
• Fever: High-grade, early
• Organ involvement:
  • Liver: hepatitis most common (80%), may be fulminant
  • Kidneys: interstitial nephritis
  • Lungs: interstitial pneumonitis, ARDS
  • Heart: myocarditis (carbamazepine, dapsone)
  • Thyroid: autoimmune thyroiditis (delayed, up to 2 years post-DRESS)

Diagnostic Criteria (RegiSCAR Score — definite DRESS: score ≥6)

• Fever >38.5°C
• Lymphadenopathy ≥2 sites
• Atypical lymphocytes in blood
• Eosinophilia ≥700 OR ≥10%
• Skin involvement (>50% BSA, ≥2 features: edema, infiltration, purpura, scaling)
• Organ involvement
• Resolution >15 days
• Exclusion of ANA, blood cultures, HAV/HBV/HCV serology

Investigations

• CBC: eosinophilia, atypical lymphocytes
• LFT, RFT (organ involvement)
• HHV-6 IgM/PCR: positive
• Skin biopsy: interface dermatitis, superficial dermal edema, atypical lymphocytes
• TSH, T4 at 3, 6, 12, 24 months (thyroid monitoring)

Treatment

1. Immediate drug withdrawal
2. Systemic corticosteroids: Prednisolone 1 mg/kg/day — slow taper over 3–6 months (rapid taper → flare; key exam point)
3. IV methylprednisolone for severe organ involvement
4. IV immunoglobulin (IVIG) for steroid-refractory cases
5. Cyclosporine for severe cases
6. Supportive: Antihistamines, emollients, wound care
7. Long-term: Thyroid function monitoring for 2 years

Prognosis

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E. PAINFUL TUMOURS OF SKIN

Mnemonic: LEND AN EGG (or BENGAL)

Individual Features:

• Triad: paroxysmal pain + point tenderness + cold hypersensitivity
• Site: subungual (most common), fingertips, palm
• Tests: Love's test (pin-point pressure → severe pain), Hildreth's test (pain disappears on tourniquet application), cold sensitivity test (immersion in cold water → pain)
• Histology: glomus cells (modified smooth muscle) around vascular spaces
• Tx: surgical excision

• Originates from arrector pili muscle
• Painful on pressure, cold, emotion (sympathetic stimulation triggers smooth muscle contraction)
• Multiple grouped firm papulonodules on trunk/extremities
• Association: HLRCC syndrome (Hereditary Leiomyomatosis and Renal Cell Carcinoma — FH gene mutation)
• Tx: excision; nifedipine/phenoxybenzamine for pain

• Young adults; solitary, deep nodule on head/neck/trunk
• Exquisite spontaneous and pressure-induced pain
• Histology: two cell types (dark peripheral, pale central) in "cannon balls"
• Tx: excision

• Young men; multiple, subcutaneous nodules on forearms
• Pain due to vasoproliferative component (fibrin microthrombi)
• Non-infiltrating vs. infiltrating types
• Tx: excision if symptomatic

• Solitary painful type in NF1 (plexiform); "buttonhole sign"
• Tx: excision

• Tender firm papule on legs (usually women)
• Dimple sign (Fitzpatrick's sign): lesion dimples on lateral compression
• Treatment: excision if symptomatic

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F. GLOMUS TUMOUR

Definition

Glomus Body Anatomy

• Located in deep dermis/subcutis, especially subungual area, fingertip pulp, palm
• Functions in temperature regulation via arteriovenous shunting
• Components: afferent arteriole (Sucquet-Hoyer canal), glomus cells (modified smooth muscle), efferent venule, unmyelinated nerve fibers

Epidemiology

• Any age; peak: 3rd–5th decade
• Women > Men for subungual type
• Multiple glomus tumours (glomuvenous malformations): autosomal dominant, GLMN gene mutation (glomulin)

Clinical Features

• Triad (Pathognomonic):
  1. Paroxysmal, lancinating pain
  2. Exquisite point tenderness
  3. Cold hypersensitivity
• Site: Subungual most common (75%) → bluish-red discoloration visible through nail plate; nail deformity; "V-shaped" groove in nail
• Other sites: fingertip pulp, palm, sole, knee, deeper tissues
• Solitary (>90%); multiple forms associated with glomuvenous malformation

Clinical Tests

• Love's test: Applying point pressure with a pin → severe localized pain (positive)
• Hildreth's test: Tourniquet applied → pain disappears; released → pain returns (positive)
• Cold sensitivity test: Immersion in cold water → pain (positive)
• Transillumination: Bluish discoloration

Investigations

• X-ray: Bony erosion/scalloping of distal phalanx (30%)
• MRI (gold standard): Hyperintense on T2, enhancing on gadolinium — most accurate for small tumours
• Ultrasound: Hypoechoic lesion with Doppler flow
• Histopathology:
  • Sheets/nests of uniform glomus cells (round, with pale cytoplasm) around vascular channels
  • Stroma of smooth muscle
  • IHC: SMA+, vimentin+

Classification

1. Glomus tumour proper (solid, most common)
2. Glomangioma (vascular predominant)
3. Glomangiomyoma (smooth muscle predominant)

Treatment

• Surgical excision: Treatment of choice — subungual approach (nail avulsion + transungual excision); recurrence rate <10%
• Laser (Nd:YAG) for superficial lesions
• Sclerotherapy for glomangiomas

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G. ACANTHOSIS NIGRICANS (AN)

Definition

Classification (Schwartz)

1. Type 1 — Obesity-associated (most common): pseudoacanthosis nigricans; improves with weight loss
2. Type 2 — Benign (familial): autosomal dominant; FGFR2/3 mutation
3. Type 3 — Endocrine: insulin resistance states (PCOS, Cushing's, acromegaly, Addison's), DM type 2
4. Type 4 — Medication-induced: nicotinic acid, corticosteroids, OCP, insulin, protease inhibitors
5. Type 5 — Malignancy-associated: gastric carcinoma (90%), other GI malignancies; most extensive; involves mucous membranes; tripe palms
6. Type 6 — Mixed

Etiopathogenesis

• Insulin resistance pathway: Hyperinsulinemia → cross-reacts with IGF-1 receptors on keratinocytes → keratinocyte and fibroblast proliferation
• Malignant type: Tumor-derived factors (TGF-α activates EGF receptors), paraneoplastic mechanism
• Drug-induced: Drugs activate same receptors
• FGFR mutations (familial type): FGFR3 gain-of-function → keratinocyte proliferation

Clinical Features

• Sites: Axillae, back of neck (most common), groin, antecubital fossa, knuckles, periumbilical
• Morphology: Hyperpigmented, velvety/papillomatous thickening; "dirty neck" appearance; skin tags (acrochordons) common
• Malignant AN: Extensive, rapid onset, mucous membrane involvement (oral, conjunctival), severe itching, tripe palms (rugose palmar skin), florid cutaneous papillomatosis
• Associated with insulin resistance markers: acanthosis nigricans on neck correlates with HOMA-IR

Acanthosis-Associated Signs

• Tripe palms (pachydermatoglyphy): Ridged, velvety palms; >90% associated with malignancy (lung, stomach)
• Sign of Leser-Trélat: Sudden eruption of multiple seborrheic keratoses (often with AN in malignancy)
• Florid cutaneous papillomatosis

Investigations

• Fasting glucose, insulin levels, HOMA-IR, HbA1c
• PCOS workup: LH/FSH, androgens, pelvic USG
• If rapid onset in non-obese adult: upper GI endoscopy, CT chest/abdomen/pelvis to exclude malignancy
• Histopathology: Hyperkeratosis, papillomatosis, mild acanthosis; pigmentation is in basal layer (not dermis); No dyskeratosis

Treatment

• Treat underlying cause: Weight loss (obesity-associated), control insulin resistance
• Topical: Retinoids (tretinoin), lactic acid, urea, salicylic acid
• Systemic: Metformin (PCOS/insulin resistance); isotretinoin for extensive cases
• Cosmetic: Dermabrasion, laser (CO₂, Er:YAG)
• Malignant AN: Treat primary malignancy → skin lesions may regress

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H. DARIER'S DISEASE (Keratosis Follicularis)

Definition

Genetics

• Gene: ATP2A2 (chromosome 12q23–24) — encodes SERCA2 (sarco-endoplasmic reticulum Ca²⁺-ATPase type 2)
• Inheritance: Autosomal dominant (variable expressivity, high penetrance)
• Mechanism: Impaired Ca²⁺ signaling → defective keratinocyte-keratinocyte adhesion (desmosome disassembly) + abnormal keratinization → acantholysis and dyskeratosis
• Onset: puberty (second decade)

Clinical Features

• Greasy, yellowish-brown, warty papules with follicular predilection
• Sites: seborrheic areas — central chest/back (V of neck), scalp, forehead, nasolabial folds, flexures
• "Dirty" malodorous lesions due to bacterial/yeast colonization
• Pruritus common; exacerbated by heat, sweat, UV, lithium, infection

• Longitudinal red and white streaks
• V-shaped notching at free edge (distal nicking)
• Subungual hyperkeratosis

• White, cobblestone papules on hard palate, buccal mucosa, gingiva ("cobblestone" papules)
• May involve esophagus, larynx

• Linear/segmental type (somatic mosaic mutation)
• Vesiculobullous type (rare)

• Kaposi varicelliform eruption (eczema herpeticum) — HSV superinfection
• Bacterial superinfection (Staph. aureus)
• Psychiatric comorbidity (epilepsy, intellectual disability, bipolar disorder via ATP2A2)

Investigations

• Histopathology (Diagnostic):
  • Acantholysis (loss of cell-cell adhesion)
  • Dyskeratosis: Corps ronds (rounded, eosinophilic acantholytic cells in spinous layer) and Corps grains (flattened, grain-like cells in granular/corneal layer)
  • Suprabasal clefting ("lacunae")
  • Villous projections of dermal papillae ("Dilapidated brick wall" pattern)
• Genetic testing: ATP2A2 sequencing if unclear

Treatment

• Trigger avoidance: Sun protection, avoid heat, occlusive clothing; prompt infection treatment
• Topical: Retinoids (adapalene, tretinoin); keratolytics (urea, salicylic acid)
• Systemic (mainstay): Oral retinoids — Acitretin (first-line, 0.5–1 mg/kg/day); isotretinoin; liarozole
• Antibiotics: For bacterial superinfection
• Antivirals (acyclovir): For KVE/eczema herpeticum
• Ciclosporin, doxycycline (anti-inflammatory): second-line
• Surgery: CO₂ laser, dermabrasion for resistant plaques

Prognosis

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I. MAJOCCHI'S GRANULOMA

Definition

Etiology

• Most common organism: Trichophyton rubrum (90%)
• Others: T. violaceum, T. tonsurans, Microsporum canis
• Routes: Trauma, shaving, topical steroids, immunosuppression

• Topical corticosteroid use (tinea incognito → Majocchi's)
• Systemic immunosuppression: HIV/AIDS, organ transplant, DM, corticosteroid therapy
• Trauma (shaving legs in women — classic scenario)
• Disrupted skin barrier

Clinical Features

• Mostly in immunocompetent women
• Perifollicular papules, pustules, nodules on legs (shaving-related)
• Localized, asymmetric
• Mildly pruritic or asymptomatic

• Deep-seated, violaceous, nodular plaques
• May ulcerate, form abscesses
• Widespread; face, trunk, extremities
• Systemic dissemination possible in severely immunocompromised

Investigations

• KOH mount: Hyphae within hair shaft (endothrix or ectothrix) — may be negative
• Fungal culture (gold standard): Sabouraud's dextrose agar — T. rubrum colonies (white fluffy surface, red/brown reverse)
• Histopathology (most important for diagnosis):
  • Suppurative and granulomatous folliculitis and perifolliculitis
  • PAS/GMS stain: fungal hyphae within follicular epithelium and surrounding dermis
  • Foreign body giant cells, epithelioid histiocytes surrounding ruptured follicles
  • PAS stain highlights fungal elements in tissue
• Dermatoscopy: Perifollicular inflammation, "red circles"

Treatment

• Topical antifungals: INEFFECTIVE alone (deep follicular infection) — key exam point
• Systemic antifungals (required):
  • Terbinafine 250 mg/day × 4–12 weeks (first-line)
  • Itraconazole 200 mg/day × 4–8 weeks
  • Fluconazole 150–400 mg/week × 4–8 weeks
• Discontinue causative topical steroids
• Treat underlying immunosuppression if possible
• Prolonged treatment in immunocompromised patients

Prognosis

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M. STABLE VITILIGO (Criteria and Assessment)

Definition

Definition of Stability (Various Criteria)

Criteria for Stability (Practical/Exam)

1. No new lesions for ≥1 year
2. No spread of existing lesions for ≥1 year
3. Negative Koebner phenomenon (no new lesion at trauma site)
4. Positive minigraft test (mini-punch grafts show repigmentation at test site — confirms surgical candidacy)
5. VIDA score 0: Vitiligo Disease Activity score (no activity in last 12 months)
6. Normal Wood's lamp: No ill-defined borders

Assessment Tools for Stability

• VIDA (Vitiligo Disease Activity) Score: Rates activity over 6 weeks, 3 months, 6 months, 1 year
• VETF (Vitiligo European Task Force): Spreading, staging, VASI
• VASI (Vitiligo Area Scoring Index): Quantifies extent
• Koebner phenomenon test: Negative = stable

Why Stability Matters

Surgical Options (brief — detailed under Q P):

• Tissue grafts: split-thickness, punch grafts, suction blister grafts
• Cellular grafts: NCES (non-cultured epidermal cell suspension/ReCell)
• Hair follicle transplant

Medical Stability-Maintaining Treatments

• Topical tacrolimus (off-label maintenance)
• Narrowband UVB: Used for maintenance of repigmentation
• Minipulse oral corticosteroids: 2.5–5 mg dexamethasone Saturday–Sunday (oral minipulse — OMP)

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N. PERIORAL DERMATITIS

Definition

Etiopathogenesis

• Most important cause: Topical corticosteroid misuse/overuse (most common trigger)
• Other triggers: fluorinated toothpaste, heavy moisturizers/barrier creams, sunscreens, inhaled/nasal steroids, OCP
• Microbiome role: Fusobacterium, Candida, Demodex mites implicated
• Impaired skin barrier function
• Predilection: young women (20–45 years); children (perioral/periocular)
• "TODS" = Topical steroid–induced perioral dermatitis

Clinical Features

• Perioral: Discrete erythematous papules, papulopustules, vesicles around mouth
• Pathognomonic: Sparing of the lip vermilion border (zone of clear skin between lesion and vermilion)
• Sites: nasolabial folds, chin, philtrum; less commonly perinasal, periocular (periorificial dermatitis)
• Burning, itching, tightness
• Sebaceous secretion on surface; mild scaling
• "Steroid rosacea" pattern: Skin atrophy, telangiectasia if long-standing topical steroid use
• Granulomatous perioral dermatitis (childhood): Children; yellow-brown granulomatous papules; periorificial distribution; no pruritus

Differential Diagnosis

• Rosacea (centrofacial, flushing, telangiectasia, no perioral predilection)
• Acne vulgaris (comedones, different distribution)
• Contact dermatitis (vesicles, positive patch test)
• Seborrheic dermatitis (scaly, greasy)

Investigations

• Clinical diagnosis — usually no investigations required
• Patch test: to exclude contact dermatitis
• Skin biopsy if atypical: perifollicular lymphohistiocytic infiltrate, occasional granulomas (granulomatous type)
• Microbiological culture if secondary infection

Treatment

1. Discontinue all topical steroids (expect initial flare — "steroid rebound"; reassure patient)
2. First-line systemic: Oral tetracyclines — doxycycline 100 mg/day or minocycline 100 mg/day × 6–12 weeks (most effective)
3. Topical (first-line): Metronidazole 0.75–1% gel/cream; Azelaic acid 15–20%; Pimecrolimus 1% cream (steroid-free)
4. For children: Topical erythromycin; oral erythromycin (if systemic needed, avoid tetracyclines <12 years)
5. Stop fluorinated toothpaste, heavy cosmetics

Prognosis

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O. KAPOSI VARICELLIFORM ERUPTION (KVE) / ECZEMA HERPETICUM

Definition

Etiology

• Atopic dermatitis (most common — eczema herpeticum)
• Darier's disease (most frequently associated among genodermatoses)
• Pemphigus foliaceus
• Seborrheic dermatitis, psoriasis, burns, Sézary syndrome
• Ichthyosis

Pathogenesis

Clinical Features

• Prodrome: Fever, malaise, regional lymphadenopathy (1–2 days before eruption)
• Lesions: Sudden widespread eruption of monomorphic, punched-out erosions arising from vesicles/pustules; umbilicated vesicles at edge
• Distribution: Superimposed on pre-existing dermatosis (face, neck, trunk in AD)
• Classic description: "Punched-out" crusted erosions/ulcers on background of eczema
• Systemic: High fever, toxicity, bacteremia (Staph. aureus superinfection common)
• Complications: Septicemia, meningitis/encephalitis, keratoconjunctivitis (corneal scarring → blindness), death (mortality 1–10% if untreated)

Investigations

• Tzanck smear: Multinucleated giant cells (acantholytic), intranuclear inclusions — rapid bedside test
• DIF (Direct immunofluorescence): HSV antigen staining
• PCR (most sensitive/specific): HSV DNA in vesicular fluid or swab
• Viral culture: Gold standard (slower, 48–72 h)
• CBC: leukocytosis; Blood culture for bacterial superinfection
• Viral serology (HSV IgM): Less useful acutely

Treatment

1. Antiviral therapy (urgent):
   • Systemic acyclovir: IV acyclovir 5–10 mg/kg 8-hourly for 7–10 days (severe/hospitalized)
   • Oral acyclovir 400 mg 5×/day or valacyclovir 1 g TDS × 7–10 days (mild-moderate)
2. Antibiotics: Antistaphylococcal (flucloxacillin/cloxacillin) for bacterial superinfection
3. Wound care: Saline soaks, antiseptic dressings
4. Ophthalmology referral: If ocular involvement (topical acyclovir ointment)
5. Avoid topical steroids during active KVE
6. Suppress AD: After resolution, optimize AD treatment to prevent recurrence; long-term acyclovir suppression (valacyclovir 500 mg OD) if frequent recurrences

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P. VITILIGO SURGERY

Indications

1. Stable vitiligo (no new/spreading lesions for ≥1 year)
2. Focal, segmental, or localized type
3. VIDA score 0
4. Failed/inadequate medical therapy
5. Negative Koebner phenomenon
6. Positive minigraft test (test grafting before procedure)

Contraindications

• Active/unstable vitiligo
• Positive Koebner phenomenon
• Unrealistic patient expectations
• Keloid tendency
• Active infections at donor/recipient sites

Classification of Surgical Techniques

A. TISSUE (Graft) Techniques

• Thin graft (0.2–0.3 mm) harvested with dermatome
• Large areas covered
• Risk: cobblestoning, color mismatch
• Used for large patches

• Most commonly used in India
• 1–2 mm punch grafts placed in recipient punch holes at 4–5 mm intervals
• Simple, OPD procedure
• Disadvantage: "cobblestone" appearance, pitting

• Suction blisters raised (vacuum, 200–300 mmHg, 45°C water); roof of blister = epidermis only (melanocytes + keratinocytes)
• Best cosmetic outcome (thin graft, less scarring)
• Colour match excellent
• Disadvantage: time-consuming; smaller areas

• FUE/FUT technique
• Follicular melanocyte reservoir repopulates vitiligo
• Used for hairy areas (eyebrows, scalp, beard)

B. CELLULAR Techniques

• Suction blister/split-thickness biopsy → enzymatic dissociation (trypsin) → single-cell suspension of melanocytes + keratinocytes
• Applied to dermabrasion/CO₂ laser-prepared recipient
• Best technique for large areas (1:10 expansion ratio)
• Best cosmetic result; minimal donor site morbidity
• Technique of Gauthier and Surlève-Bazeille

• Melanocytes cultured in vitro (2–3 weeks) → expanded → transplanted
• Highest expansion ratio (1:80)
• Expensive, requires specialized lab; risk of culture contamination

• Similar to NCES; used widely

Post-Operative Care

• Dressing: Tie-over/non-adherent dressing × 7–10 days
• NB-UVB 2–3×/week from post-op week 2–4 (enhances repigmentation)
• Topical tacrolimus

Outcome Assessment

• Repigmentation: >90% considered excellent
• Colour match graded on visual analogue scale
• Average repigmentation: 8–12 weeks post-procedure

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Q. DIFFERENTIAL DIAGNOSIS OF ACNEIFORM ERUPTIONS

Definition

• Absence of comedones (the hallmark differentiator)
• Uniform monomorphic lesions
• Atypical distribution
• Identifiable cause (drug, infection, endocrine)

Differential Diagnosis — Classification

I. Drug-Induced Acneiform Eruptions

II. Endocrine/Hormonal

• Polycystic ovary syndrome (PCOS): Hyperandrogenism; lower face, jawline, chin; associated hirsutism, oligomenorrhea
• Cushing's syndrome/disease: Steroid acne pattern; moon face, buffalo hump
• Congenital adrenal hyperplasia (CAH): Androgenic acne; 21-hydroxylase deficiency
• Acromegaly: GH excess → sebaceous gland hyperplasia

III. Occupational/Exogenous

• Chloracne: Chlorinated aromatic compounds (dioxin, PCBs) — comedones + cysts, retroauricular area; pathognomonic for halogenated hydrocarbon exposure
• Oil acne: Mineral oils, cutting oils — mechanical folliculitis
• Cosmetic acne (Acne cosmetica): Comedogenic cosmetics → closed comedones
• Pomade acne: Hair pomades → hairline comedones

IV. Infectious Mimics

• Gram-negative folliculitis: Complication of long-term antibiotic-treated acne; Klebsiella, Proteus, E. coli; persistent perinasal/perioral pustules
• Pityrosporum (Malassezia) folliculitis: Pruritic monomorphic papulopustules on upper trunk/back/shoulders; KOH: spores in follicle; responds to antifungals, not antibiotics
• Demodex folliculitis: Monomorphic pustules; perioral/cheek; Demodex mites on KOH/biopsy
• Hot tub folliculitis: Pseudomonas aeruginosa; after hot tub/whirlpool use; trunk/buttocks

V. Inflammatory Conditions

• Rosacea (papulopustular): Centrofacial; flushing, telangiectasia; NO comedones; triggers (heat, alcohol, spicy food)
• Perioral dermatitis: Perioral distribution; sparing of vermilion; topical steroid history
• Acne keloidalis nuchae: Follicular papulopustules on occiput/nape → keloidal plaques; Black males
• Folliculitis decalvans: Scarring alopecia with follicular pustules; Staph. aureus
• SAPHO syndrome: Severe acne + palmoplantar pustulosis + bone/joint inflammation

VI. Neonatal/Pediatric

• Neonatal acne (neonatal cephalic pustulosis): Malassezia; first 4 weeks; face; self-limiting
• Infantile acne: 3–6 months; true comedones; may scar

VII. Acne-like syndromes

• HAIR-AN syndrome: Hyperandrogenism, Insulin resistance, Acanthosis nigricans
• PAPA syndrome: Pyogenic arthritis, Pyoderma gangrenosum, Acne (autoinflammatory)
• Apert syndrome (acne tetrad): Acne + sebaceous hyperplasia + hyperhidrosis + follicular retention cysts

Key Differentiating Points for Exam:

• Comedones absent → think drug/acneiform, not true acne
• Monomorphic lesions → drug-induced
• Pruritic → Malassezia folliculitis
• Retroauricular/axillary comedones → chloracne
• Hot tub history → Pseudomonas
• Trunk distribution + pruritus → Malassezia

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R. ERYTHEMA NODOSUM

Definition

Etiopathogenesis

• Type IV hypersensitivity reaction (immune complex deposition in septal vessels of subcutaneous fat)
• Immune complex deposition → complement activation → neutrophil infiltration → septal panniculitis
• Septal panniculitis without vasculitis — hallmark histological feature

Clinical Features

• Predominantly women (3:1 F:M); peak age 20–40 years
• Prodrome: Fever, malaise, arthralgia, URTI symptoms (1–2 weeks before skin lesions)
• Lesions:
  • Bilateral, symmetric, tender, erythematous nodules/plaques
  • Ill-defined, deep-seated
  • Sites: anterior shin most common; less commonly thighs, forearms
  • Overlying skin red → violaceous → bruise-like (erythema contusiforme)
  • DO NOT ulcerate (differentiates from nodular vasculitis/erythema induratum)
• Course: Self-limiting; each lesion resolves in 3–6 weeks; no scarring; no ulceration
• Recurrences if underlying cause persists

Special Variant: Löfgren's Syndrome

Investigations

• Throat swab + ASO titer (Streptococcal)
• Chest X-ray (TB, sarcoidosis — hilar adenopathy)
• Mantoux test / IGRA (TB)
• ACE levels (sarcoidosis)
• CBC, ESR, CRP (activity)
• Stool culture (Yersinia, Salmonella)
• Serum calcium (sarcoidosis)
• Pregnancy test (in women)
• IBD workup: colonoscopy if GI symptoms

• Septal panniculitis — inflammation confined to fibrous septa between fat lobules
• Early: neutrophilic infiltrate in septa
• Late: histiocytes, lymphocytes, Miescher's granulomas (radial arrangement of histiocytes around a central cleft — pathognomonic)
• NO vasculitis (distinguishes from erythema induratum)
• NO lobular necrosis

Treatment

• NSAIDS: Indomethacin 75–150 mg/day (first-line), naproxen, aspirin
• Potassium iodide (KI) 400–900 mg/day — effective, mechanism unclear (suppresses neutrophil chemotaxis); drug of choice in recurrent/chronic EN
• Colchicine 0.5 mg BD: for recurrent cases
• Rest and elevation of legs
• Compression bandaging

• Systemic corticosteroids (prednisolone 40 mg/day, tapering) — only after excluding TB and other infections
• Hydroxychloroquine for sarcoid-related EN

Prognosis

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Exam Tips Summary:

• Darier's disease: ATP2A2 mutation; Corps ronds & Corps grains; acitretin is treatment
• DRESS onset: 2–8 weeks; HHV-6 reactivation; slow steroid taper 3–6 months
• Glomus tumour tests: Love's + Hildreth's + cold sensitivity (triad)
• SCLE: Anti-Ro/SSA; no scarring; midface spared; terbinafine #1 drug cause
• Majocchi's: T. rubrum; topical antifungals alone FAIL; systemic terbinafine needed
• EN: septal panniculitis, NO vasculitis, NO ulceration; KI for recurrent type
• Vitiligo surgery: NCES best for large areas; stability ≥1 year mandatory
• EMPD: CK7+/CK20− = primary; Mohs MMS is gold standard
• Acneiform eruptions: absence of comedones is key differentiatorAll 17 complete 10-mark answers are above. Here's a quick navigation guide:

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Quick Index

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MD Dermatology — 3rd Year PG Theory Examination

Complete 10-Mark Answer Bank

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A. PEMPHIGUS ERYTHEMATOSUS (PE) / SENEAR-USHER SYNDROME

Definition

Epidemiology

• Rare; occurs in adults; no sex predilection
• Drug-induced cases: penicillamine, captopril, propranolol, cefuroxime, heroin
• Reported association with myasthenia gravis and thymoma

Etiopathogenesis

• Autoantibodies: Anti-desmoglein 1 (Dsg1) - same as pemphigus foliaceus; anti-Dsg3 absent
• Additional autoantibodies may target BP230 (bullous pemphigoid antigen 1) and periplakin
• Antinuclear antibody (ANA) positive in ~30% of patients at low titers
• UV light triggers disease by upregulating Dsg1 expression and exposing autoantigens
• Overlap mechanism: IgG autoantibodies cause acantholysis in the subcorneal layer (PF pattern) + immune complex deposition at DEJ (LE pattern)
• HLA associations: HLA-DR4, HLA-DR14 (similar to LE)

Clinical Features

• Sites: Seborrheic/photo-exposed areas - nose, malar cheeks, ears (butterfly distribution), scalp, chest, upper back - resembling SLE/seborrheic dermatitis
• Lesions: Erythematous, thickly crusted plaques; may be bullous, vesicular, or hyperkeratotic
• Classic description: "Impetiginous lesions amid bullae on the scalp, chest and extremities"
• Nikolsky sign: Positive (lateral pressure → new blister)
• Mucous membrane involvement: typically ABSENT (as in PF)
• Systemic features: generally absent; course is indolent/benign compared to PV
• Pruritus variable; burning sensation common
• May worsen with UV exposure (photosensitive component)

Histopathology

• Same as pemphigus foliaceus:
  • Subcorneal/superficial intraepidermal acantholysis
  • Sparse inflammatory infiltrate
  • Eosinophilic spongiosis

Immunofluorescence (Hallmark)

• DIF (Diagnostic): IgG + C3 at TWO sites:
  1. Intercellular spaces of epidermis (pemphigus pattern - "chicken wire")
  2. DEJ - continuous granular deposits (lupus band pattern)
• IIF: Anti-intercellular antibody positive (as in PF); anti-BMZ negative
• Serology: ANA positive (low titer) in 30%; anti-dsDNA usually negative

Investigations

• DIF (key diagnostic test)
• IIF on monkey esophagus
• ELISA for anti-Dsg1 antibodies (positive; anti-Dsg3 negative)
• ANA, anti-dsDNA, complement levels
• Evaluate for underlying systemic lupus features

Differential Diagnosis

Treatment

1. Photoprotection: Strict sun avoidance + broad-spectrum SPF ≥50 (essential - reduces UV-triggered flares)
2. Topical corticosteroids: High potency (clobetasol) - often sufficient in mild cases
3. Systemic corticosteroids: Prednisolone 0.5–1 mg/kg/day if widespread; usually lower doses required than in PV
4. Immunosuppressants (steroid-sparing): Azathioprine 1–2 mg/kg/day; mycophenolate mofetil 2 g/day
5. Hydroxychloroquine: For lupus overlap component (200–400 mg/day)
6. Drug-induced PE: Withdraw offending drug; may resolve spontaneously

Prognosis

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B. SUBACUTE CUTANEOUS LUPUS ERYTHEMATOSUS (SCLE)

Definition

Epidemiology

• Women > Men (approximately 3:1); Caucasians predominant
• Peak onset: 3rd–5th decade
• Accounts for ~10% of all LE patients

Etiopathogenesis

• Genetic susceptibility: HLA-DR3, HLA-B8, HLA-DQ2 (strongest HLA associations in LE)
• Central autoantibody: Anti-Ro/SSA (70–100%); Anti-La/SSB (30–40%)
• UV radiation → Ro/SSA antigen expression on keratinocyte surface → antibody-mediated complement activation + CD4+ cytotoxic T-cell attack → vacuolar interface dermatitis
• Drug-induced SCLE (important): ~33% of SCLE is drug-induced
  • Most common: terbinafine (most frequently identified in Swedish population study)
  • Others: TNF-α inhibitors, anti-epileptics, proton pump inhibitors (omeprazole), hydrochlorothiazide, CCBs, checkpoint inhibitors (pembrolizumab, nivolumab), ACE inhibitors
  • Cutaneous lesions may or may not clear after drug discontinuation

Clinical Features

1. Papulosquamous (psoriasiform) type (~50%): Scaly erythematous papules/plaques resembling psoriasis or eczema
2. Annular/polycyclic type (~50%): Annular lesions with raised erythematous borders, central clearing, fine scaling at periphery; may coalesce into polycyclic arcs

• Upper back, V of neck, shoulders, lateral aspects of face
• Midface characteristically SPARED (in contrast to DLE which prominently involves the nose/cheeks)
• Extensor upper extremities

• No scarring (hallmark)
• No follicular plugging
• No dermal atrophy
• Dyspigmentation (especially hypopigmentation) may occur as sequela

• Arthralgia/arthritis (~50%)
• Sicca symptoms (Sjögren's overlap)
• Serositis (pleuritis, pericarditis) - minority
• Renal involvement: <10% (contrast with SLE where >50%)
• ~10–15% fulfill ACR criteria for SLE

Investigations

• Anti-Ro/SSA: 70–100% (hallmark antibody)
• Anti-La/SSB: 30–40%
• ANA: Positive in 60–80% (low to moderate titer, speckled/cytoplasmic pattern)
• Anti-dsDNA: Negative or low titer (usually negative)
• Histopathology:
  • Interface dermatitis - vacuolar type (basal vacuolation)
  • Superficial perivascular lymphocytic infiltrate
  • Epidermal atrophy, melanin incontinence
  • Absent: follicular plugging, dermal mucin, scarring (all absent - differentiates from DLE)
• DIF: Lupus band (IgG, IgM, C3 at DEJ) in ~60%; less reliable than in DLE
• CBC (lymphopenia, anemia), urinalysis, complement (C3, C4), anti-dsDNA, ANA profile

Treatment

1. Photoprotection (cornerstone): Broad-spectrum SPF ≥50 applied daily; avoid UV-A/B; protective clothing
2. Topical: Potent corticosteroids; tacrolimus/pimecrolimus (for face; steroid-sparing)
3. Antimalarials (first-line systemic):
   • Hydroxychloroquine 200–400 mg/day (6.5 mg/kg/day max)
   • Add quinacrine 100 mg/day if inadequate response (combination)
4. Second-line:
   • Dapsone 50–100 mg/day
   • Thalidomide 50–100 mg/day (effective but teratogenic)
   • Acitretin/isotretinoin
5. Third-line/refractory:
   • Methotrexate 7.5–15 mg/week
   • Mycophenolate mofetil 1–3 g/day
   • Belimumab (anti-BLyS/BAFF monoclonal antibody)
6. Drug-induced SCLE: Withdraw causative drug; monitor for resolution

Prognosis

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C. DRESS SYNDROME (Drug Reaction with Eosinophilia and Systemic Symptoms)

Definition

Epidemiology

• Incidence: 1/1000 to 1/10,000 drug exposures (for high-risk drugs)
• No strong sex predilection; all ages

Etiopathogenesis

• Genetic polymorphisms affecting drug detoxification - e.g., inability to detoxify toxic arene oxide metabolites of aromatic anticonvulsants (phenytoin, carbamazepine, phenobarbital) → reactive metabolite accumulation → immune activation
• Explains cross-reactivity between aromatic anticonvulsants

• HLA allele associations (drug-specific):
  • HLA-B*58:01 → allopurinol (Han Chinese, Thai, Korean)
  • HLA-B*57:01 → abacavir
  • HLA-A*31:01 → carbamazepine (European)
  • HLA-B*13:01 → dapsone (Chinese)
• IL-5 drives eosinophilia; drug-specific T cells activated in skin/internal organs

• Sequential herpesvirus reactivation is a hallmark:
  • HHV-6 most consistently implicated (~70% of DRESS); transmitted to skin-infiltrating CD4+ T cells
  • Also HHV-7, EBV, CMV
  • EBV-transformed B cells produce EBV when triggered by culprit drugs

• Aromatic anticonvulsants: carbamazepine, phenytoin, phenobarbital, lamotrigine
• Allopurinol (most common overall cause)
• Sulfonamides (cotrimoxazole, sulfasalazine)
• Dapsone (antibiotic + antileprotic)
• Abacavir, nevirapine (antiretrovirals)
• Minocycline, vancomycin, mexiletine, strontium ranelate

Clinical Features

• Onset: 2–8 weeks after drug initiation (long latency - key differentiator)
• Fever: High-grade (>38.5°C), early, often before rash

• Begins as morbilliform exanthem on face and upper trunk → spreads caudally
• Progresses to edematous, confluent, extensive eruption ± erythroderma
• Facial edema (periorbital, perioral) - HALLMARK of DRESS (distinguishes from other drug reactions)
• Less common: vesicles, follicular/non-follicular pustules (~20%, overlap with AGEP), purpuric lesions
• Mucosal involvement: mild if present (unlike SJS/TEN where mucosal ulceration is prominent)

• Lymphadenopathy: Generalized, tender (hepatic and lymph node involvement most common)
• Hepatitis (~80%): Most common and potentially life-threatening organ involvement; elevated ALT >100 U/L; may progress to fulminant hepatic failure
• Renal: Interstitial nephritis
• Pulmonary: Interstitial pneumonitis, ARDS
• Cardiac: Myocarditis (associated especially with carbamazepine, dapsone)
• Thyroid: Autoimmune thyroiditis - delayed manifestation occurring up to 2 years after DRESS (critical long-term monitoring point)
• Hematophagocytic lymphohistiocytosis (HLH): Rare but life-threatening complication

Diagnostic Criteria

• Fever >38.5°C
• Enlarged lymph nodes ≥2 sites
• Atypical lymphocytes
• Eosinophilia (≥700/mm³ or ≥10%)
• Skin rash >50% BSA + ≥2 skin features (edema, infiltration, purpura, desquamation)
• Organ involvement (liver, kidney, lung, heart, others)
• Resolution >15 days
• Exclusion of alternative diagnoses

1. Maculopapular rash >3 weeks after drug initiation
2. Prolonged symptoms after drug discontinuation
3. Fever >38°C
4. Liver abnormalities (ALT >100 U/L) or other organ involvement
5. Leukocyte abnormality (leukocytosis, atypical lymphocytes >5%, or eosinophilia >1.5×10⁹/L)
6. Lymphadenopathy
7. HHV-6 reactivation

Investigations

• CBC: eosinophilia, atypical lymphocytes, leukocytosis
• LFT, RFT, troponin (cardiac)
• HHV-6 IgM/PCR (serum, skin)
• Skin biopsy: interface dermatitis, superficial dermal edema, atypical lymphocytes, eosinophilic infiltrate
• Serial TSH/T4 at 3, 6, 12, 24 months (thyroid monitoring)

Treatment

1. Immediate drug withdrawal - most important step
2. Systemic corticosteroids (first-line):
   • Prednisolone 1 mg/kg/day
   • SLOW taper over 3–6 months (rapid taper causes rebound/flare - critical exam point)
   • IV methylprednisolone pulses for severe organ involvement (hepatitis, myocarditis)
3. IVIG (1–2 g/kg) for steroid-refractory cases or HLH
4. Cyclosporine 3–5 mg/kg/day for refractory cases
5. Antihistamines + emollients for symptom control
6. Long-term monitoring: Thyroid function every 3–6 months for 2 years
7. Cross-reactive drugs: Avoid entire class (all aromatic anticonvulsants cross-react); provide a drug alert card

Prognosis

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D. MYCETOMA (Madura Foot / Maduromycosis)

Definition

1. Tumefaction (swelling/induration)
2. Draining sinuses
3. Grains (aggregates of causative organisms discharged from sinuses)

Classification

Epidemiology

• "Mycetoma Belt": 15°N–30°S latitude (Sudan, India, Mexico, Somalia, Yemen, Senegal)
• India: Madurella mycetomatis (eumycetoma) in south; Nocardia and Actinomadura (actinomycetoma) more common
• Predominantly males, outdoor workers (farmers, laborers), age 20–40 years
• Mode of infection: Penetrating injury by thorns, splinters (Acacia thorn - a vector); causative organisms are soil/plant saprophytes

Etiopathogenesis

• Organisms inoculated subcutaneously via penetrating trauma
• No underlying immunodeficiency required (unlike opportunistic fungi)
• Evasion of host defenses: Cell wall thickening and melanin deposition (in dark-grain fungi) prevent phagocytosis
• Organisms form grains within abscess cavities - protective aggregates
• Spreads by direct contiguous extension through fascial planes → involves muscle, tendon, bone
• Distant metastasis: exceptionally rare
• Results in chronic suppurative granulomatous inflammation → fibrosis → bone destruction

Clinical Features

1. Tumefaction: Firm to brawny swelling, progressive enlargement; initially painless
2. Draining sinuses: Multiple, open on skin surface; discharge seropurulent fluid + grains
3. Grains: Key pathognomonic feature - visible to naked eye in discharge

• Early: Firm, painless, subcutaneous nodule at site of inoculation
• Progressive: Papules, plaques; multiple draining sinus tracts; "peppered" surface appearance
• Advanced: Massive deformity, bone involvement (periosteal erosion, lytic lesions), destroyed joint architecture

• Foot/lower leg: most common (60-70%) - "Madura foot"
• Hand
• Back/chest wall (characteristic of Nocardia)
• Head and neck (unusual)

• Black/dark grains → ALWAYS fungi (e.g., Madurella mycetomatis)
• Red/pink grains → ALWAYS actinomycetes (e.g., Actinomadura pelletieri)
• White/pale grains → EITHER fungi OR actinomycetes (e.g., A. madurae = actino; Scedosporium, Fusarium = fungi)

Investigations

• Obtained from sinus discharge, squeezing sinus edges, or curettage
• Grains: 250–1000 μm, visible with naked eye
• KOH mount: Shows broad fungal hyphae (eumycetoma) vs. fine filaments (actinomycetoma - hard to see in KOH)

• Chronic suppurative granulomatous inflammation
• Neutrophil abscesses + scattered giant cells + fibrosis
• Grains in center of inflammation
• PAS and GMS (Grocott-Gomori) stains highlight fungal elements
• Gram stain/Fite stain for actinomycetes

• Multiple media: Sabouraud's dextrose agar, blood agar
• Morphologic + physiologic characteristics for species ID
• Molecular PCR for definitive identification

• X-ray: Periosteal erosion and proliferation, lytic lesions ("soap bubble" pattern), bone sclerosis
• MRI/CT: Detects soft tissue extent and bone involvement at early stage; "dot-in-circle" sign on MRI (grains surrounded by fibrous capsule - highly specific for mycetoma)
• USG: Hyperechoic dots (grains) within hypoechoic lesion

Differential Diagnosis

• Chronic osteomyelitis (bacterial or tuberculous)
• Actinomycosis (commensal sites - mouth, cecum)
• Botryomycosis (staphylococcal soft tissue infection with granules)
• Chromoblastomycosis (verrucous, no sinuses, no bone involvement, sclerotic bodies)
• Cutaneous TB, deep fungal infections

Treatment

• First-line: Dapsone 100 mg BD + streptomycin 14 mg/kg/day IM (Destombes-Mariat regimen) in 4-week cycles with 4-week rest periods
• Alternative: Cotrimoxazole (TMP-SMX) + rifampicin + streptomycin
• For Nocardia: Amikacin + imipenem; moxifloxacin for recalcitrant cases
• Treatment duration: months to years; outcomes generally good

• Itraconazole 400 mg/day (first-line; most studied)
• Voriconazole 200–400 mg/day (for resistant/unresponsive cases)
• Ketoconazole 200–400 mg/day
• Terbinafine: worth attempting
• Treatment response unpredictable; may slow progression but rarely curative with antifungals alone

• Wide surgical excision (with antifungal coverage) for localized eumycetoma
• Amputation may be necessary for advanced cases with massive bone destruction
• Early surgical intervention with drug cover gives best results
• Surgery alone has very high recurrence

Prognosis

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E. LEG ULCERS — Causes, Etiopathogenesis, and Management of Venous Leg Ulcers

Definition

Causes of Leg Ulcers

Venous Leg Ulcers — Etiopathogenesis

1. Primary valve incompetence of saphenous veins (superficial)
2. Incompetence of perforating veins (Cockett perforators at medial gaiter region)
3. Deep vein incompetence or obstruction (post-DVT, primary valvular insufficiency)

• Dilated, incompetent veins → venous pooling → fluid transudation → edema

1. Fibrin cuff theory (Browse & Burnand, 1982):
   • Venous hypertension → increased capillary pressure → pericapillary fibrin deposition ("fibrin cuffs") → acts as barrier to oxygen and nutrient diffusion → tissue ischemia and necrosis
   • Not entirely confirmed
2. White cell trapping theory (Thomas et al.):
   • Venous hypertension → leukocyte (neutrophil) margination and trapping in capillaries → leukocyte activation → release of proteolytic enzymes (MMPs) + reactive oxygen species → endothelial damage + free radical-mediated tissue damage
   • Increased mast cells, monocytes, lymphocytes found in peri-ulcer tissue
3. Growth factor "trap" theory:
   • Plasma proteins (fibrin, albumin, alpha-2-macroglobulin) leak into tissues → "trap" growth factors (TGF-β, PDGF) → growth factors unavailable for wound healing → impaired repair
4. Senescent fibroblasts:
   • Fibroblasts in ulcer surrounds are in a "senescent" (non-proliferating) state → impaired healing
   • Proteolytic enzymes (MMPs) raised → degrade extracellular matrix
5. Haemosiderin toxicity:
   • RBC extravasation → haemosiderin deposition → brown pigmentation (lipodermatosclerosis/LDS pattern)
   • Haemosiderin itself may be directly injurious to tissue

Clinical Features of Venous Leg Ulcers

• Location: Medial gaiter region (between calf muscles and ankle); medial malleolus most common site (Cockett perforators)
• Morphology: Shallow, irregularly shaped ulcer with gently sloping edges; floor contains pink granulation tissue + variable slough + exudate; not punched-out (contrast with arterial ulcers)
• Surrounding skin: Haemosiderosis (brown pigmentation), lipodermatosclerosis (LDS) - thickening/induration/fibrosis of calf skin ("inverted champagne bottle" appearance), varicose eczema (varicose dermatitis)
• Symptoms: Aching, heaviness; mild pruritus before ulcer formation; ulcers often relatively painless (compare with arterial ulcers which are severely painful)
• Raised ulcer edge → biopsy to exclude Marjolin's ulcer (squamous cell carcinoma in chronic venous ulcer)
• Varicose veins may or may not be present

Investigations

1. Ankle-Brachial Pressure Index (ABPI): All new ulcers; ABPI ≥0.9 = adequate perfusion (venous); ABPI 0.5–0.8 = mixed; ABPI <0.5 = critical ischaemia (compression contraindicated)
2. Duplex ultrasound: Assess deep and superficial venous reflux, perforator incompetence; also excludes deep vein thrombosis
3. Biopsy: For non-healing or atypical ulcers to exclude carcinoma
4. Blood tests: CBC, glucose, HbA1c, ESR/CRP, ANA, ANCAs, ANCA (vasculitis workup), sickle cell test if applicable
5. Bacterial swab: Only if clinically infected (routine swabbing unhelpful)

Management of Venous Leg Ulcers

• Reduces venous hypertension - the pathological basis
• Ideal interface pressure for pure venous ulcer: 35–40 mmHg
• Multi-layer compression bandaging (4-layer - Charing Cross regimen):
  1. Layer 1 - Orthopaedic wool: distributes pressure, absorbs exudate, protects bony prominences
  2. Layer 2 - Cotton crepe: smooths wool, holds in place
  3. Layer 3 - Elastic bandage: first compressive layer (~1/3 of pressure)
  4. Layer 4 - Cohesive bandage: second compressive layer (~2/3 of pressure)
• Two-layer compression hosiery: Equally cost-effective
• Mixed ulcers (ABPI 0.5–0.8): Modified compression at 30 mmHg is safe and effective with monitoring
• Contraindicated: ABPI <0.5 (critical limb ischaemia)

• Debridement: Mechanical (sharp), autolytic (hydrogels), enzymatic (collagenase), larval (maggot) therapy for sloughy wounds
• Dressings: Non-adherent; choice based on exudate level:
  • Low exudate: hydrocolloid, hydrogel
  • High exudate: alginate, foam dressings
  • Infected ulcer: silver-containing dressings (Ag+), iodine dressings
• Antimicrobials: Only if clinically infected; avoid routine antibiotics (promotes resistance)

• Treatment of superficial venous incompetence accelerates healing and reduces recurrence
• Expeditious vascular surgery referral recommended
• Options: Endovenous laser ablation (EVLA), radiofrequency ablation (RFA), foam sclerotherapy, conventional surgery (Trendelenburg/SAPHENA procedures)
• Early Venous Reflux in Non-Healing Leg Ulcers (EVRA trial): Early intervention group had faster healing and fewer recurrences

• Oxpentifylline (pentoxifylline) 400 mg TDS: Improves microvascular circulation; enhances healing when added to compression (Cochrane evidence)
• Aspirin 300 mg/day: May improve healing by reducing platelet aggregation
• Zinc supplementation (if deficient)
• Treat underlying conditions: Anaemia, hyperglycaemia, rheumatoid arthritis

• Split-thickness skin grafting (STSG): For large, non-healing ulcers
• Pinch grafting: Simple OPD technique for smaller ulcers
• Provides immediate wound cover; stimulates healing

• Compression hosiery (23–32 mmHg): Life-long use; most important for preventing recurrence
• Leg elevation at rest (above heart level)
• Regular walking and calf muscle exercise (enhances venous pump)
• Weight reduction in obese patients
• Treat underlying venous disease

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F. MYCETOMA (Detailed/Repeat — see Topic D above for complete answer)

Quick Structured 10-Mark Framework for Mycetoma:

• Eumycetoma: Madurella mycetomatis (most common globally, dark grains), Scedosporium apiospermum (pale, temperate)
• Actinomycetoma: Nocardia brasiliensis (Central America), Actinomadura madurae, Streptomyces somaliensis (Sudan)

• Triad: tumefaction + sinuses + grains
• Black grains = always fungi; red = always actinomycetes; white = either
• Stages: painless nodule → draining sinuses → bone destruction + deformity
• Foot (60%) most common; chest = Nocardia

• KOH of grains; culture on Sabouraud's
• Histopathology: suppurative granulomatous inflammation; PAS/GMS stain; grains in center of abscesses
• X-ray: periosteal erosion, lytic lesions
• MRI: "dot-in-circle" sign (pathognomonic)

• Actinomycetoma: dapsone + streptomycin (Destombes-Mariat); co-trimoxazole + rifampicin; good prognosis
• Eumycetoma: itraconazole/voriconazole; surgery for localized; amputation for advanced; poor response
• Topical antifungals ineffective (deep infection)

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Quick Reference Summary Table

High-yield exam points:

• PE: "Both ICS AND DEJ positive on DIF" - the only pemphigus with lupus band
• SCLE: terbinafine is now the most common drug cause (not hydrochlorothiazide)
• DRESS: 3-6 month steroid taper mandatory; thyroid monitoring for 2 years post-DRESS
• Mycetoma: black grains = always fungi; red grains = always actinomycetes; topical antifungals useless
• Venous ulcer: ABPI mandatory before compression; 4-layer bandage = 35-40 mmHg; early venous ablation reduces recurrence