1. explain chronic eczema , forms, cilical features and management 2. cellulitis in short for 5 marks 3. classify and explain skin lesions in breif
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1. Chronic Eczema - Explanation, Forms, Clinical Features & Management
Definition & Overview
Eczema (from Greek ekzein - "to boil forth/effervesce") is a chronic, inflammatory skin disease. The word encompasses several disorders and is often used synonymously with atopic dermatitis. The hallmark histological finding is spongiosis (serous exudate between epidermal cells) with dermal perivascular lymphoid infiltrate.
Stages:
- Acute: Red, edematous plaque with small grouped vesicles
- Subacute: Erythematous plaques with scale or crusting
- Chronic: Lichenification, dry scale, minimal spongiosis with compact hyperkeratosis, irregular acanthosis, and collagen thickening in the papillary dermis
(Andrews' Diseases of the Skin, Clinical Dermatology)
Forms of Eczema
1. Atopic Dermatitis (Atopic Eczema)
The most common form. A chronic, inflammatory skin disease with pruritus and a course of exacerbations and remissions. Associated with asthma, allergic rhinoconjunctivitis, food allergies - the "atopic march."
Age-specific patterns:
- Infantile AD: Begins after 2 months - erythema and scaling of cheeks, scalp, neck, extensor extremities. Significant exudate, crusts; lichenification develops.
- Childhood AD: Less exudative. Classic sites - antecubital and popliteal fossae, flexor wrists, ankles, eyelids, neck. Lichenified indurated plaques with scattered excoriated papules.
- Adult AD: Flexural predominance persists; often hands and eyelids. Disease may persist into adulthood.
Diagnostic criteria (Hanifin & Rajka):
Major criteria (must have 3):
- Pruritus
- Typical morphology and distribution (flexural lichenification in adults; facial/extensor involvement in infants)
- Chronic or relapsing history
- Personal or family history of atopic disease
Minor criteria (must have 3+):
Xerosis, ichthyosis, keratosis pilaris, elevated IgE, early age of onset, recurrent skin infections (especially S. aureus/HSV), Dennie-Morgan infraorbital fold, pityriasis alba, food hypersensitivity, white dermatographism, etc.
2. Nummular Eczema (Discoid Eczema)
Coin-shaped, well-demarcated, pruritic, oozing plaques - commonly on the legs and dorsum of hands. Often associated with dry skin and stress. More common in middle-aged adults.
3. Dyshidrotic Eczema (Pompholyx)
Deep-seated vesicles on the sides of fingers, palms, and soles with intense pruritus. Often triggered by sweating, stress, or contact allergens.
4. Hand Eczema (Contact/Irritant)
Very common; may be irritant contact, allergic contact, or endogenous. Erythema, vesicles, fissuring, scaling of the hands.
5. Ear Eczema / Nipple Eczema
Site-specific variants; nipple eczema is important to differentiate from Paget's disease.
6. Seborrhoeic Dermatitis
Affects sebum-rich areas (scalp, face, chest). Greasy yellowish scales on erythematous base.
Clinical Features of Chronic Eczema
| Feature | Description |
|---|---|
| Pruritus | Prominent, worse at night; leads to insomnia |
| Lichenification | Skin thickening with accentuated skin lines from chronic scratching |
| Xerosis | Dry, dull skin |
| Excoriations | Linear scratch marks |
| Scale | Drier than in acute phase |
| Fissures | Especially on palms/soles |
| Secondary infection | S. aureus colonization with weeping, crusting, folliculitis |
| Distribution | Flexural areas in adults; extensor/facial in infants |
Management of Chronic Eczema (Atopic Dermatitis)
General Measures
- Identify and avoid triggers (heat, sweating, wool, allergens, irritants)
- Maintain cool environment; avoid overheating
- Stress management
Skin Care / Emollients
- Regular moisturizers immediately after bathing ("soak and smear")
- Ointment-based emollients preferred
- Dilute sodium hypochlorite (bleach) baths twice weekly (1/4 US cup in 20 gallons water) to decolonize S. aureus and provide anti-inflammatory effect
Topical Therapy
- Topical corticosteroids - first-line; ointments preferred; must be potency-appropriate for site and age
- Topical calcineurin inhibitors (tacrolimus, pimecrolimus) - steroid-sparing; used on face and flexures; particularly useful in children
Antipruritics
- Sedating antihistamines (diphenhydramine, hydroxyzine, doxepin) - primarily via sedation
- Non-sedating antihistamines (cetirizine, loratadine) - for co-existing environmental allergies
- Gabapentin, SSRIs, mirtazapine - for refractory pruritus
- Topical pramoxine, menthol, phenol-containing moisturizers for localized itch
Phototherapy
- Narrowband UVB or broadband UVB for moderate-severe disease
Systemic Immunosuppression (severe/refractory)
- Cyclosporine - fastest onset; 3–6 mg/kg/day; not for long-term use due to nephrotoxicity
- Methotrexate - 10–25 mg/week in adults; efficacy similar to cyclosporine but slower onset; take folic acid concurrently
- Azathioprine - dose guided by thiopurine methyltransferase level; slower onset, may be preferable long-term
- Mycophenolate mofetil - 6 weeks to effect; 20-40% non-response rate
- Dupilumab (biologic) - IL-4/IL-13 blocker; FDA approved for moderate-severe AD
Biologics & Newer Agents
- Dupilumab (anti-IL-4Rα)
- Ustekinumab - some benefit (Th17 pathway involvement)
- Omalizumab - only 20% achieve >50% reduction; limited role
Management of Acute Flare
- Identify and treat precipitating cause (infection, stress, contact allergen)
- Wet wrap therapy (soaking and smearing) - 3-4 days breaks severe flares
- Short course systemic corticosteroids as last resort
Infection Management
- S. aureus: dilute bleach baths + intranasal mupirocin to reduce nasal carriage; oral antibiotics (cephalosporins, TMP-SMX, clindamycin, doxycycline) for recurrent infections
- Eczema herpeticum (HSV superinfection): systemic acyclovir + antistaphylococcal antibiotic
(Andrews' Diseases of the Skin, Clinical Dermatology)
2. Cellulitis (Short Note - 5 Marks)
Definition
Cellulitis is a suppurative inflammation involving the subcutaneous tissue, often following a wound or skin breach.
Etiology
- Streptococci cause ~75% of cases
- Staphylococci cause the majority of the remainder
- Portal of entry: wounds, tinea pedis (very common on leg), eczema, insect bites
Clinical Features
- Local: Intense rapidly spreading erythema, warmth, swelling, tenderness; the area pits on pressure
- Systemic: Malaise, fever, chills (may be absent in mild cases)
- Central area may become nodular with vesicle formation that ruptures and discharges pus and necrotic material
- Lymphangitis: Streaks from affected area toward regional lymph nodes; lymphadenopathy
Complications (particularly in children and immunocompromised)
- Gangrene
- Metastatic abscesses
- Severe sepsis
Diagnosis
- Primarily clinical
- Blood cultures and skin aspirates rarely positive
- If open wound present, wound culture may be positive
Differential Diagnosis
| Condition | Differentiating Feature |
|---|---|
| Stasis dermatitis | No fever/pain; bilateral; medial malleoli |
| Allergic contact dermatitis | Itchy, not painful |
| Eosinophilic cellulitis | Less painful; eosinophilia (not neutrophilia) |
| Erythema migrans (Lyme) | Less painful red patch; bulls-eye appearance |
Management
- Outpatient (no systemic toxicity): Dicloxacillin or cephalexin for 5 days
- MRSA suspected: TMP-SMX, clindamycin, or doxycycline
- Severe/systemic toxicity: IV antibiotics; hospitalization
Recurrent Cellulitis
Predisposing factors: diabetes, alcoholism, immunodeficiency, tinea pedis, venous stasis, lymphedema. Chronic recurrence leads to elephantiasis nostras. Managed with long-term maintenance antibiotics and compression therapy.
(Andrews' Diseases of the Skin, Clinical Dermatology)
3. Classification and Explanation of Skin Lesions
Skin lesions are classified into Primary lesions (arising de novo from previously normal skin) and Secondary lesions (arising from evolution, trauma, or infection of primary lesions).
A. PRIMARY LESIONS
I. Flat (Non-Palpable) Lesions
| Lesion | Size | Description |
|---|---|---|
| Macule | < 1 cm | Flat, even with skin surface; perceptible only as area of color change (e.g., freckle, petechiae) |
| Patch | ≥ 1 cm | Flat area of color change, larger than macule (e.g., vitiligo, fixed drug eruption) |
II. Raised (Palpable) Solid Lesions
| Lesion | Size | Description |
|---|---|---|
| Papule | < 1 cm | Elevated or depressed solid lesion; can be sessile, pedunculated, flat-topped, dome-shaped, umbilicated (e.g., lichen planus, warts) |
| Plaque | ≥ 1 cm | Solid plateau-like elevation or depression with diameter ≥ 1 cm; often formed by confluence of papules (e.g., psoriasis) |
| Nodule | ≥ 1 cm | Palpable, domed/spherical/ovoid lesion; may be solid or cystic; types: epidermal, dermal, subcutaneous (e.g., lipoma, lymphoma cutis) |
| Wheal | Variable | Transient, edematous, erythematous raised lesion (e.g., urticaria); due to dermal edema |
III. Fluid-Filled Lesions
| Lesion | Size | Contents | Example |
|---|---|---|---|
| Vesicle | < 1 cm | Clear serous fluid (serum, blood, lymph) | Herpes simplex, varicella, dyshidrosis |
| Bulla | ≥ 1 cm | Clear serous fluid | Pemphigus, bullous pemphigoid, burn |
| Pustule | Any size | Pus (neutrophils + debris) | Folliculitis, impetigo, pustular psoriasis |
Vesicles and bullae arise from cleavage within the epidermis (intraepidermal) or at the dermal-epidermal junction (subepidermal).
B. SECONDARY LESIONS
| Lesion | Description |
|---|---|
| Scale | Loose, keratinous flakes from abnormal stratum corneum; types include pityriasiform, psoriasiform (silvery/micaceous), seborrhoeic (greasy/yellow), ichthyosiform |
| Crust | Dried exudate (serum + cells + keratin) overlying a damaged epidermis; "honey-colored" in impetigo |
| Erosion | Shallow, moist loss of epidermis only; heals without scarring (e.g., ruptured vesicle) |
| Ulcer | Full-thickness loss of epidermis AND dermis; heals with scar |
| Fissure | Linear crack in epidermis/dermis from excessive dryness or tension; common on palms/soles |
| Lichenification | Skin thickening with accentuated skin lines from repeated rubbing/scratching; seen in chronic eczema |
| Atrophy | Thinning of epidermis (cigarette-paper wrinkling) or dermis (depressed lesion) |
| Excoriation | Linear scratch marks from mechanical trauma |
| Scar | Fibrous replacement after dermal damage |
| Keloid | Hypertrophic scar extending beyond wound margins |
Summary Table: Primary Lesion Classification (Fitzpatrick's)
| PRIMARY LESION | SIZE | TOPOGRAPHY | CONTENTS |
|---|---|---|---|
| Macule | < 1 cm | Flat | Color change only |
| Patch | ≥ 1 cm | Flat | Color change only |
| Papule | < 1 cm | Raised/Depressed | Solid |
| Plaque | ≥ 1 cm | Raised/Depressed | Solid |
| Nodule | ≥ 1 cm | Raised | Solid or fluid |
| Vesicle | < 1 cm | Raised | Fluid (serous/blood) |
| Bulla | ≥ 1 cm | Raised | Fluid (serous/blood) |
| Pustule | < 1 cm | Raised | Pus |
| Erosion | Any | Depressed | N/A |
| Ulceration | Any | Depressed | N/A |
(Fitzpatrick's Dermatology, Vol. 1 & 2; Andrews' Diseases of the Skin)
Key Memory Aid for Classification:
- Flat = Macule/Patch (size distinguishes)
- Solid raised = Papule/Plaque/Nodule (size/depth distinguishes)
- Fluid = Vesicle/Bulla/Pustule (size and content distinguish)
- Secondary lesions arise from changes to primary lesions (scale, crust, erosion, ulcer, lichenification, scar)
Create a visual poster classifying primary vs secondary skin lesions with images5 marks eczema and 5 marks cellulitis
write eczema for 15 marks and cellulitis for 5 marks to the point not inn so much detail
Here are exam-ready answers, structured and to the point.
ECZEMA (15 Marks)
Definition
Eczema (derived from Greek ekzein - "to boil forth") is a chronic, relapsing, inflammatory skin disease characterized by pruritus, erythema, vesiculation, and lichenification. The terms eczema and dermatitis are used interchangeably.
Etiology / Types (Forms)
| Type | Key Feature |
|---|---|
| Atopic Dermatitis | Most common; associated with asthma, allergic rhinitis, elevated IgE |
| Contact Dermatitis | Irritant (soaps, detergents) or Allergic (nickel, rubber) |
| Nummular (Discoid) Eczema | Coin-shaped plaques; common on legs |
| Dyshidrotic Eczema | Deep vesicles on palms, soles, finger sides |
| Seborrhoeic Dermatitis | Greasy scales on scalp, face, chest |
| Hand Eczema | Occupational; erythema, fissuring, scaling of hands |
Pathology (Histology)
- Spongiosis - hallmark; serous fluid between epidermal cells
- Dermal perivascular lymphoid infiltrate
- Exocytosis (lymphocytes in epidermis)
- Chronic stage: compact hyperkeratosis, irregular acanthosis, collagen thickening in papillary dermis
Stages & Clinical Features
Acute Stage
- Intense erythema, edema
- Grouped vesicles (may weep/ooze)
- Severe pruritus (worse at night - causes insomnia)
- Exudate, crusting
Subacute Stage
- Erythematous plaques
- Scaling and crusting
- Less vesiculation
Chronic Stage
- Lichenification - skin thickening with exaggerated skin lines
- Dry scales
- Excoriations, fissures
- Hyperpigmentation
Atopic Dermatitis - Age Distribution
| Age | Distribution |
|---|---|
| Infantile (0-2 yrs) | Cheeks, scalp, extensor surfaces |
| Childhood (2-12 yrs) | Antecubital & popliteal fossae, flexor wrists |
| Adult | Flexures, hands, eyelids |
Diagnostic Criteria (Hanifin & Rajka)
Major (3 of 4 required):
- Pruritus
- Typical morphology and flexural distribution
- Chronic/relapsing history
- Personal/family history of atopy
Minor (3+ required): xerosis, keratosis pilaris, elevated IgE, early onset, recurrent infections, Dennie-Morgan fold, white dermatographism, pityriasis alba, food hypersensitivity
Complications
- Secondary S. aureus infection - weeping, honey-coloured crusts
- Eczema herpeticum - HSV superinfection; widespread vesiculopustular eruption; systemic illness
- Erythroderma (rare)
- Ocular: keratoconus, anterior subcapsular cataracts
Management
General / Trigger Avoidance
- Avoid wool, soaps, extreme heat, sweating, stress
- Identify and avoid contact allergens
Skin Care
- Regular emollients/moisturizers - cornerstone of therapy; apply after bathing
- Bleach baths (dilute sodium hypochlorite) twice weekly - decolonizes S. aureus, anti-inflammatory
Topical Therapy
- Topical corticosteroids - first-line; ointments preferred; potency matched to site and age
- Topical calcineurin inhibitors (tacrolimus, pimecrolimus) - steroid-sparing; safe on face and flexures
Antipruritics
- Sedating antihistamines (hydroxyzine, diphenhydramine) - mainly for sedation/sleep
- Gabapentin, SSRIs - refractory pruritus
Phototherapy
- Narrowband UVB - moderate to severe disease
Systemic Immunosuppressants (severe/refractory)
- Cyclosporine - fastest onset; 3-6 mg/kg/day; not for long-term use
- Methotrexate - 10-25 mg/week; slower onset; give folic acid
- Azathioprine - long-term option; dose by TPMT level
- Mycophenolate mofetil - well tolerated; 6 weeks to effect
Biologics
- Dupilumab (anti-IL-4/IL-13) - FDA approved; most effective biologic for moderate-severe AD
Infection Treatment
- Oral antibiotics for S. aureus (cephalosporins, TMP-SMX, clindamycin)
- Systemic acyclovir for eczema herpeticum
CELLULITIS (5 Marks)
Definition
Cellulitis is an acute suppurative inflammation of the subcutaneous tissue, often following a breach in the skin surface.
Etiology
- Streptococci - ~75% of cases
- Staphylococci - most of the remainder
- Portal of entry: wounds, tinea pedis (common on legs), eczema, insect bites
Clinical Features
- Rapidly spreading erythema, warmth, swelling, tenderness
- Area pits on pressure
- Central area may vesiculate, rupture, and discharge pus/necrotic material
- Lymphangitis - red streaks toward regional lymph nodes
- Systemic: fever, malaise, chills
Complications (immunocompromised/children)
- Gangrene, metastatic abscesses, severe sepsis
Diagnosis
- Primarily clinical
- Blood cultures/skin aspirates rarely positive
- Wound culture useful if open wound present
Differentials
| Condition | Key Difference |
|---|---|
| Stasis dermatitis | Bilateral, no fever, no pain |
| Allergic contact dermatitis | Itchy, not painful |
| Erythema migrans (Lyme) | Bulls-eye pattern, less pain |
| Eosinophilic cellulitis | Eosinophilia, less painful |
Management
| Severity | Treatment |
|---|---|
| Mild/No systemic toxicity | Oral dicloxacillin or cephalexin x 5 days |
| MRSA suspected | TMP-SMX, clindamycin, or doxycycline |
| Severe/Toxic | IV antibiotics + hospitalization |
Recurrent cellulitis: Long-term prophylactic antibiotics + compression therapy to reduce lymphedema.
(Andrews' Diseases of the Skin, Clinical Dermatology)
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