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Major Skin Emergencies in the Emergency Room

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Overview: Classification of Skin Emergencies

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1. Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)

What They Are

• SJS: <10% body surface area (BSA) epidermal detachment
• SJS/TEN overlap: 10-30% BSA detachment
• TEN (Lyell syndrome): >30% BSA detachment

Causative Drugs

"More than 100 medications have been reported to cause SJS and TEN."

• TMP-SMX (1-3 per 100,000)
• Nevirapine
• Lamotrigine (1:1,000 adults; 3:1,000 children)
• Carbamazepine (14:100,000) - especially in HLA-B*1502-positive Asians
• Allopurinol (most common cause in Europe currently)
• NSAIDs, other anticonvulsants, antibiotics (sulfonamides, penicillins)

Clinical Presentation

• Prodrome: fever, influenza-like symptoms 1-4 days before rash
• Skin: deep red/dusky macules on face and trunk, spreading rapidly; "2-zone" or atypical targetoid lesions; central desquamation; bullae formation, then sloughing
• Two or more mucosal surfaces are almost always involved in SJS: oral (hemorrhagic crusting), conjunctival, urethral, vaginal, anal
• Symptoms: photophobia, dysphagia, dysuria, cough (tracheobronchial involvement)
• "Pure TEN": dusky macular erythema with rapid full-thickness epidermal separation (no targetoid lesions)

Mortality Risk: SCORTEN

• Age >40
• Malignancy present
• BSA involved >10%
• Tachycardia (HR >120)
• BUN >28 mg/dL
• Serum bicarbonate <20 mEq/L
• Blood glucose >14 mmol/L

Management

• Immediate cessation of causative drug - single most important intervention
• ICU or burn unit admission; multidisciplinary team
• Fluid resuscitation: approximately 2/3 of the Parkland formula (less than burn victims)
• Nutritional support and monitoring for sepsis
• Wound care: leave involved epidermis in place as biological dressing; nonstick dressings; silver-impregnated dressings; minimize tape-to-skin; IV lines at uninvolved sites
• Mucosal care: nonstick dressings to separate eroded mucosal surfaces; ophthalmology consult (risk of symblepharon/blindness); gynecology and urology consults as needed; amniotic membrane application for eyes
• Systemic immunosuppression (controversial, no consensus):
  • European practice: Cyclosporine 3-6 mg/kg/day (divided)
  • US practice: IVIG 1 g/kg/day for 4 days ± corticosteroids
  • Etanercept: shown beneficial in moderate RCT (Asia)
  • Early short-course high-dose steroids may help in some cases

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2. Necrotizing Fasciitis

Definition

Risk Factors

Clinical Recognition - "Hard to Diagnose Early"

• Erythema, warmth, swelling, pain "out of proportion to appearance"
• Skin becomes brawny, violaceous, then dusky/gray
• Late: skin necrosis, bullae, frank gangrene, crepitus (gas-forming organisms)
• Systemic: fever, tachycardia, hypotension, altered mental status
• Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC score): CRP, WBC, Hgb, Na, creatinine, glucose

Pathogenic Types

• Type I (polymicrobial): streptococci, staphylococci, gram-negatives, anaerobes (most common)
• Type II (monomicrobial): Group A Streptococcus (flesh-eating disease) or Staphylococcus aureus
• Type III: Clostridial (gas gangrene - myonecrosis)
• Type IV: Fungal (Candida, Mucor) - immunocompromised hosts

Management - Surgical Emergency

"Rapid surgical intervention remains the mainstay of therapy...Surgical intervention less than 24 hours following onset is associated with improved clinical outcomes." - Fitzpatrick's Dermatology

1. Immediate surgical consult - do not delay for further imaging if clinical diagnosis is clear
2. Radical debridement of all necrotic tissue; staged daily re-debridements until clean
3. Wound closure: vacuum-assisted closure (VAC) devices + skin grafting after source control
4. Amputation may be required for severe limb disease (especially in diabetics)
5. Broad-spectrum antibiotics (IDSA 2014 guidelines): vancomycin OR linezolid OR daptomycin PLUS one of: piperacillin-tazobactam / carbapenem / ceftriaxone + metronidazole / fluoroquinolone + metronidazole - narrow based on tissue culture
6. Fluid resuscitation + electrolyte monitoring (significant wound drainage)
7. IVIG: limited evidence; may consider in Group A Strep NF (neutralizes exotoxins)
8. Hyperbaric oxygen: insufficient data; ongoing research

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3. Meningococcemia and Purpura Fulminans

Meningococcemia - A Classic Emergency

• Initial: small, irregular petechiae with a "smudged" appearance
• Distribution: extremities most common; also palms, soles, mucous membranes, conjunctiva
• Petechiae in 60% of patients on presentation; higher in children 1-18 years (74%)
• Critical sign: rapid increase in number and size of petechiae correlates with fulminant disease

Purpura Fulminans

• Retiform purpura (branching, stellate necrosis)
• Skin necrosis extending to subcutaneous tissue, muscle, and bone
• Low protein C levels
• Gangrene of digits and distal extremities

Management

1. Immediate IV benzylpenicillin (or ceftriaxone 2g IV if penicillin allergy) - do not delay for LP if patient is unstable
2. Blood cultures before antibiotics if possible - but do not delay treatment
3. ICU admission, sepsis resuscitation (fluids, vasopressors, oxygen)
4. DIC management: FFP, cryoprecipitate, platelets as guided by coagulation profile
5. Protein C concentrate may be considered in purpura fulminans
6. Surgical care for gangrenous tissue (may require amputation)
7. Close contacts: chemoprophylaxis (rifampicin, ciprofloxacin, or ceftriaxone)

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4. DRESS Syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms)

Features

• Onset: 2-8 weeks after starting offending drug (longer latency than SJS)
• Rash: morbilliform eruption (face, upper trunk, extremities), often with facial edema
• Systemic involvement: fever, lymphadenopathy, hepatitis (most common), nephritis, pneumonitis, myocarditis, thyroiditis
• Hematologic: eosinophilia (hallmark), atypical lymphocytes
• Viral reactivation: HHV-6, EHV-7, CMV, EBV commonly reactivate and may drive severity

Management

1. Stop the offending drug immediately
2. Systemic corticosteroids: prednisone 1-2 mg/kg/day (mainstay; taper slowly over weeks to months to prevent relapse)
3. Monitor liver function, renal function, CBC regularly
4. Monitor for HHV-6 reactivation; antivirals (valganciclovir) if severe or HHV-6-driven
5. Avoid re-exposure to causative drug; cross-reactivity within anticonvulsant class

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5. Staphylococcal Scalded Skin Syndrome (SSSS)

Features

• Primarily affects neonates and children <5 years (adults if immunocompromised/renal failure)
• Caused by exfoliative toxins A and B from Staphylococcus aureus (usually phage type 71)
• Toxins cleave desmoglein-1 in the superficial epidermis
• Prodrome: fever, irritability, skin tenderness
• Rash: starts perioral/periorbital, then generalized erythema, then flaccid bullae and desquamation
• Nikolsky sign positive (lateral pressure on erythematous skin causes epidermal slipping)
• No mucosal involvement (distinguishes from SJS/TEN - mucosae contain desmoglein-3 which is not affected by the toxin)

Management

1. Hospitalization; neonates to NICU
2. Anti-staphylococcal antibiotics: IV nafcillin or oxacillin; clindamycin (inhibits toxin production); vancomycin if MRSA suspected
3. Fluid and electrolyte replacement
4. Wound care: gentle handling; nonstick dressings; emollients
5. Prognosis: excellent in children with treatment (mortality <5%); worse in adults (~60%)

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6. Anaphylaxis with Urticaria/Angioedema

Skin Signs

• Urticaria: pruritic, raised, evanescent wheals; can be anywhere on body
• Angioedema: deeper, non-pitting swelling; face, lips, tongue, throat (life-threatening when laryngeal)
• Together with systemic features (bronchospasm, hypotension, tachycardia) = anaphylaxis

Management (ABC-first approach)

1. Epinephrine 0.3-0.5 mg IM (anterolateral thigh) - first-line, do not delay
2. Airway: supplemental O2; early intubation or surgical airway if laryngeal edema
3. IV fluids: 1-2 L normal saline for hypotension
4. Antihistamines: diphenhydramine (H1) + ranitidine/famotidine (H2) - adjuncts only, NOT first-line
5. Systemic corticosteroids: methylprednisolone IV - reduces biphasic reactions
6. Observe for minimum 4-6 hours (24 hours if severe); prescribe epinephrine auto-injector on discharge
7. Allergist referral for identification and avoidance of trigger

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7. Erythroderma (Exfoliative Dermatitis)

Definition

Causes ("5 Ps + D")

• Psoriasis (most common underlying disease)
• Pityriasis rubra pilaris
• Primary dermatoses (atopic dermatitis, contact dermatitis, seborrheic)
• Drugs (sulfonamides, gold, isoniazid, captopril, many others)
• Paraneoplastic (Sézary syndrome - cutaneous T-cell lymphoma)
• De novo / idiopathic (in ~30%)

Systemic Complications

• Hypothermia or hyperthermia (disrupted thermoregulation)
• High-output cardiac failure (massive cutaneous vasodilation - up to 30% increase in skin blood flow)
• Protein/fluid loss through skin
• Hypoalbuminemia, edema
• Secondary bacterial infection/sepsis
• Renal failure

Management

1. Hospitalize - often ICU
2. Treat precipitating cause (stop drug, treat underlying psoriasis/dermatitis)
3. Temperature control: warm room, blankets (patients cannot thermoregulate)
4. Fluid and electrolyte replacement
5. Nutritional support (high caloric needs from hypermetabolic state)
6. Emollients and wet compresses for skin comfort
7. Skin biopsy for diagnosis (especially to exclude Sézary syndrome)
8. Treat secondary infections with appropriate antibiotics
9. Disease-specific systemic therapy once diagnosis is confirmed

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Quick ER Reference Summary

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• Andrews' Diseases of the Skin, Clinical Dermatology - SJS/TEN (pp. 139-142)
• Fitzpatrick's Dermatology, 2-Volume Set - Necrotizing fasciitis management; meningococcemia and purpura fulminans (pp. 2812-2813)
• Goldman-Cecil Medicine - Urticaria, angioedema, anaphylaxis
• Sabiston Textbook of Surgery - Necrotizing fasciitis surgical management
• IDSA 2014 Guidelines (cited within Fitzpatrick's) - antimicrobial therapy for necrotizing infections

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Emergency Room Skin Disorders

Based on Tintinalli's Emergency Medicine & Rosen's Emergency Medicine

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Approach to the Dermatologic Patient in the ED

1. Severe generalized drug/immune reactions (SJS, TEN, DRESS, pemphigus)
2. Infectious emergencies with skin signs (meningococcemia, necrotizing fasciitis, cellulitis)
3. Vascular/purpuric disorders (purpura fulminans)

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PART 1 - SEVERE GENERALIZED SKIN DISORDERS

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1. Erythema Multiforme (EM)

"Until the early 1990s, erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis were classified as a continuum of a spectrum of disease; it is now appreciated that erythema multiforme is distinct from the more serious or even life-threatening Stevens-Johnson syndrome and toxic epidermal necrolysis."

• Adults: drugs (barbiturates, penicillins, sulfonamides, NSAIDs, phenothiazines)
• Children: predominantly infections - HSV-1/HSV-2 account for 70-90% of all EM cases; Mycoplasma pneumoniae also common

• Abrupt onset rash, sometimes preceded by burning; pruritus usually absent
• Classic "target" (iris) lesion: 2-3 zones - dark center, lighter surrounding zone, red outer ring
• Symmetric distribution on hands, feet, extensor surfaces
• EM minor: limited distribution
• EM major: oral mucosal involvement; ophthalmologic lesions in ~70% of cases

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2. Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN)

"Some authorities include Stevens-Johnson syndrome as a severe form of erythema multiforme major, whereas others consider it a less severe form of toxic epidermal necrolysis. Perhaps the most appropriate classification approach for the emergency physician is to recognize that the severity and extent of epidermal detachment reflects the spectrum of disease."

• SJS: <10% BSA epidermal detachment
• SJS/TEN overlap: 10-30% BSA
• TEN: >30% BSA detachment

• Flu-like prodrome (fever, malaise, myalgias) 1-4 days before skin lesions
• Maculopapular rash progressing rapidly to confluent erythema, bullae, and skin sloughing
• Mucous membranes: painful erosions of oral, ocular, urogenital mucosae in virtually all SJS cases
• Positive Nikolsky sign (lateral pressure causes epidermal separation)
• May have ARDS, hepatitis, renal failure

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3. Pemphigus Vulgaris

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4. Exfoliative Dermatitis (Erythroderma)

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5. DRESS Syndrome (Drug Rash with Eosinophilia and Systemic Symptoms)

"DRESS syndrome is a severe adverse drug reaction that usually develops within 8 weeks of initiation of drug therapy. Aromatic anticonvulsants (such as phenytoin and phenobarbital), allopurinol, and sulfa medications are the most common culprits."

• Onset 2-8 weeks after drug initiation
• Fever + rash + internal organ involvement (liver, kidneys, hematologic most common)
• Rash polymorphic: can mimic exfoliative dermatitis or SJS
• Eosinophilia in ~30%; hepatic and renal dysfunction
• Genetic predisposition present; must warn family members

1. Immediate cessation of suspected culprit drug
2. Systemic steroids in severe cases (hepatitis, pneumonitis, or extensive exfoliative dermatitis)
3. Supportive care: antipyretics, antipruritic medications
4. Hospital admission; monitor LFTs, renal function, CBC

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PART 2 - PURPURIC / VASCULAR EMERGENCIES

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6. Meningococcemia

"A rash is frequently noted on presentation and is an invaluable clue to the correct diagnosis early in the disease course." - Tintinalli

• Petechiae, urticaria, hemorrhagic vesicles, macules, maculopapules
• Classic: petechiae on extremities and trunk, palms, soles, head, mucous membranes
• Petechiae evolve into palpable purpura with gray necrotic centers - pathognomonic
• Mechanism: organism invades and destroys endothelium causing infectious vasculitis

• Blood cultures (positive in 50-80%); obtain before antibiotics if no delay
• Lumbar puncture in stable patients without DIC
• Gram stain of petechial scrapings: gram-negative diplococci in up to 2/3 of cases
• PCR of buffy coat/CSF - most sensitive and specific; unaffected by prior antibiotics
• CBC (bandemia typical), coagulation profile, metabolic panel, CXR, lactate, echo if myocarditis suspected

• Dexamethasone 0.4-0.6 mg/kg/day q6h x 4 days for bacterial meningitis - give before first antibiotic dose if possible
• Corticosteroids in meningococcemia without meningitis: controversial; consider only if persistent shock despite fluids + vasopressors (possible adrenal insufficiency)
• Fulminant meningococcemia: airway management + IV fluid resuscitation + vasopressors; FFP for DIC bleeding; hemodialysis if anuric; correct electrolyte/acid-base abnormalities
• Plasmapheresis, blood exchange, ECMO: described but limited data

• Rifampin 10 mg/kg (max 600 mg) PO q12h x 4 doses (neonates: 5 mg/kg; warn about urine/secretion discoloration)
• Alternative: Ceftriaxone IM 125 mg (children <15 years) or 250 mg (>12 years) - preferred in pregnancy
• Alternative: Ciprofloxacin 500 mg PO single dose (adults)

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7. Purpura Fulminans

"Purpura fulminans is a rare vascular disorder characterized by fever, shock, multiorgan failure, and the rapid development of hemorrhagic skin necrosis."

1. Widespread ecchymoses
2. Hemorrhagic bullae
3. Epidermal necrosis

• Treat underlying sepsis aggressively
• DIC management: FFP, cryoprecipitate, platelets
• Protein C concentrate where available
• ICU; surgical care for gangrenous tissue

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PART 3 - INFECTIOUS SKIN EMERGENCIES

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8. Cellulitis and Erysipelas

• Admit if: systemic toxicity, diabetes mellitus, alcoholism, immunosuppression
• Discharge if: healthy, no systemic toxicity - outpatient with 2-3 day follow-up; mark the perimeter of infection with indelible marker to monitor progression

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9. Necrotizing Fasciitis

"Hallmark of fasciitis are the presence of marked systemic toxicity and pain out of proportion to local findings." - Tintinalli

• Asymmetric fascial thickening
• Gas tracking along fascial planes (pathognomonic)
• Focal fluid collections
• MRI: sensitive but not entirely specific

1. Antibiotics - Triple therapy: Penicillin or cephalosporin + aminoglycoside + clindamycin (clindamycin inhibits toxin production)
2. Immediate surgical debridement - do not delay
3. ICU admission; fluid resuscitation; monitor electrolytes

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PART 4 - URTICARIA, ANGIOEDEMA, AND ANAPHYLAXIS

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10. Urticaria

"Urticaria, or hives, is a cutaneous reaction marked by acute onset of pruritic, erythematic wheals of varying size that generally are described as 'fleeting.'" - Tintinalli

• Identify and remove offending agent
• H1 antihistamines ± corticosteroids (note: adding corticosteroids to non-sedating antihistamines may not improve relapse or itch reduction)
• Epinephrine for severe or refractory cases
• H2 antihistamine (ranitidine/famotidine) in severe/chronic/unresponsive cases
• Cold compresses for symptomatic relief
• Refer to allergist for severe, recurrent, or refractory cases

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11. Angioedema

"Angioedema of the tongue, lips, and face has the potential for airway obstruction." - Tintinalli

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PART 5 - PEDIATRIC INFECTIOUS SKIN EMERGENCIES

12. Kawasaki Disease

"Kawasaki's disease is the leading cause of acquired heart disease in children."

1. Bilateral non-exudative conjunctivitis
2. Cervical lymphadenopathy
3. Erythema of lips and oral mucosa (strawberry tongue)
4. Skin changes of extremities (erythema, edema, desquamation)
5. Rash (variable morphology; vesicles not described; perineal predilection)

• Peak age: 18-24 months; <6 months or >9 years have poorer outcomes
• Mortality <0.5% - mainly from coronary artery aneurysm rupture
• Most devastating complication: sudden cardiac death from coronary aneurysms

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Quick Reference: Disposition Summary

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• Tintinalli's Emergency Medicine: A Comprehensive Study Guide - Chapters 14, 142, 192-194, 249-250
• Rosen's Emergency Medicine: Concepts and Clinical Practice - Chapter 118 (Meningococcemia), Chapter 42 (Soft Tissue)

Emergency Room Skin Disorders - Management

Based on Tintinalli's Emergency Medicine & Rosen's Emergency Medicine

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ED APPROACH TO SKIN DISORDERS

• Duration, rate of progression, % BSA involved
• Medication history (especially drugs started within 2-8 weeks) - EM, SJS, TEN, DRESS are drug-induced
• Exposures: chemicals, foods, animals, insects, plants, travel, occupational, ill contacts
• Sexual history where relevant
• Painful rash = red flag; rarely self-limiting

"Use the burn rule of nines to estimate the degree of skin involvement in disorders with widespread distribution."

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PART 1 - LIFE-THREATENING SKIN EMERGENCIES

1. Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN)

• SJS: <10% BSA epidermal detachment
• SJS/TEN overlap: 10-30%
• TEN: >30% BSA - mortality up to 90% with SCORTEN ≥5

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2. Pemphigus Vulgaris

• Remove any drug trigger
• Fluid and electrolyte resuscitation
• Immunosuppressive therapy (prednisone + rituximab or azathioprine)
• IVIG (immunoglobulin therapy)
• Plasmapheresis for severe cases
• Antibiotics only for confirmed infection
• Admit: ICU/burn unit; intensivist + dermatologist

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3. Exfoliative Dermatitis (Erythroderma)

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4. DRESS Syndrome

• Eosinophilia occurs in ~30% of cases
• Rash may resemble exfoliative dermatitis OR SJS
• Genetic predisposition is present - discuss risk with patient's family members

1. Immediately stop the causative drug
2. Systemic corticosteroids for severe cases with hepatitis, pneumonitis, or extensive dermatitis
3. Antipyretics and antipruritic agents (supportive)
4. Admit to hospital; monitor LFTs, renal function, CBC, eosinophil count

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5. Purpura Fulminans

"Purpura fulminans is a rare vascular disorder characterized by fever, shock, multiorgan failure, and the rapid development of hemorrhagic skin necrosis."

1. Widespread ecchymoses
2. Hemorrhagic bullae
3. Epidermal necrosis (nose, ears, genitalia, distal extremities)

• Treat underlying sepsis (antibiotics + vasopressors)
• DIC management: FFP, cryoprecipitate, platelets
• Protein C concentrate
• ICU; surgical care for gangrenous areas

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PART 2 - INFECTIOUS SKIN EMERGENCIES

6. Necrotizing Fasciitis

"Hallmark of fasciitis are the presence of marked systemic toxicity and pain out of proportion to local findings."

1. Immediate surgical consultation - do not wait for imaging if clinical diagnosis clear
2. IV antibiotics: triple therapy - penicillin/cephalosporin + aminoglycoside + clindamycin
3. Surgical debridement within <24 hours - staged daily re-debridements
4. Fluid resuscitation + electrolyte monitoring
5. ICU admission

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7. Cellulitis and Erysipelas

"Mark the patient's skin with an indelible marker along the perimeter of infection so healing can be determined at follow-up."

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8. Skin Abscesses, Furuncles, and Carbuncles

• Small furuncles: warm compresses to promote drainage; reassess in 2-3 days
• Sitz baths for buttock/perineal furuncles
• Large furuncles, carbuncles, abscesses: incision and drainage (I&D) required
  • Simple needle aspiration inadequate for MRSA abscesses
  • Use No. 11 or 15 scalpel blade over area of greatest fluctuation
  • Use US to guide incision length and depth
  • Break up loculations with a hemostat
  • Pack the cavity with gauze; reassess at 48 hours

1. Obtain consent; universal precautions including face shield
2. Position for access; prep with povidone-iodine; drape
3. Infiltrate from the side over the abscess; distend cavity with lidocaine
4. Incise over area of greatest fluctuation
5. Express contents; break loculations
6. Pack with gauze wick; arrange 48-hour follow-up

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PART 3 - VIRAL SKIN CONDITIONS IN THE ED

9. Herpes Zoster (Shingles)

• Initiate within first 72 hours of symptom onset for maximum benefit
• Reduces healing time, new lesion formation, risk of postherpetic neuralgia
• Immunocompromised patients with severe involvement: hospitalize for IV acyclovir
• Local care: aluminum acetate compresses TID + antibiotic ointment
• Treat pain aggressively (may be severe)

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10. Herpes Simplex (HSV)

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PART 4 - PAPULOSQUAMOUS AND COMMON ED CONDITIONS

11. Scabies

• Treat all household members and close contacts concurrently
• Wash linens and recently worn clothes in hot water; dry on high heat

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12. Contact Dermatitis and Atopic Dermatitis

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13. Fungal Infections

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14. Head/Scalp Conditions

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15. STI-Related Skin Conditions

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16. Urticaria and Angioedema

• Identify and remove offending agent
• H1 antihistamines ± corticosteroids (note: adding steroids to non-sedating antihistamines alone may not reduce relapse risk)
• H2 antihistamine (ranitidine/famotidine) in severe/chronic/unresponsive cases
• Epinephrine 0.3-0.5 mg IM for severe or refractory cases
• Cold compresses for symptomatic relief

• ACE inhibitor angioedema occurs in 0.1-0.7% of ACE-I users
• Mechanism: bradykinin/substance P mediated - does NOT respond well to antihistamines/steroids/epinephrine
• Airway must be secured early - progression can be rapid and unpredictable

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PART 5 - TOPICAL THERAPY PRINCIPLES IN THE ED

"If it's dry, wet it; if it's wet, dry it."

• Ointments (petroleum base, no preservatives): best for chronic dry conditions; winter months
• Creams (oil + water + preservative): most versatile; suitable for any body surface; may cause drying with chronic use
• Gels: useful for scalp, beard areas
• Patients allergic to cream preservatives: switch to ointment formulation

• Emollients/moisturizers: reduce dryness, skin friction, and tightness; ointments best for chronic conditions
• Open wet dressings (tap water or saline): reduce discomfort; cleanse by painlessly loosening crusts
• Capsaicin 0.025% TID × 4 weeks: antipruritic via substance P depletion; not for age <10 years
• Pramoxine 1-2% or EMLA: topical anesthetics for pruritus; limited high-quality evidence

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RAPID REFERENCE: Disposition by Condition

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• Tintinalli's Emergency Medicine: A Comprehensive Study Guide - Chapters 14, 152, 192-193, 248-253
• Rosen's Emergency Medicine: Concepts and Clinical Practice - Chapters 84, 118, 152

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Secondary Lesions, Diagnostic Labs, and Management of Skin Disorders in the Emergency Room

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PART 1 - SKIN LESION MORPHOLOGY

Primary vs. Secondary Lesions

"Secondary lesions...include crusts, scales, fissures, erosions, ulcerations, excoriations, atrophy, scarring, and lichenification." - Tintinalli TABLE 248-3

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TINTINALLI TABLE 248-3 - Complete Lesion Morphology

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TINTINALLI TABLE 248-2 - Lesion Configuration Descriptors

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TINTINALLI TABLE 248-4/5 - Differential Diagnosis by Lesion Morphology

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Distribution Pattern → Differential Diagnosis (Tintinalli TABLE 246-1)

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PART 2 - DIAGNOSTIC TESTS FOR SKIN DISORDERS IN THE ED

1. Potassium Hydroxide (KOH) Preparation

1. Place skin scrapings on a glass slide
2. Add a coverslip
3. Apply KOH 10-40% solution to the edge of the coverslip - it will be drawn under by capillary action
4. Apply heat to the underside of the slide (match or lighter) until bubbles appear under coverslip
5. Visualize under 10× magnification; use low condenser and light settings; focus up and down rapidly

• True hyphae (dermatophyte infection): long, branching green rods of constant width that cross cell borders

• Molluscum bodies: oval discs with homogeneous cytoplasm
• Spores in hair: small, round spores packed closely within the hair shaft (endothrix = Trichophyton; ectothrix = Microsporum)

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2. Tzanck Smear

"The presence of the multinucleated giant cell does not distinguish between herpes simplex, herpes zoster, and varicella syndromes." - Tintinalli

1. Air-dry the specimen
2. Stain with Giemsa or Wright stain
3. View under low power - scan for epithelial cells
4. Positive finding: multinucleated giant cells (syncytium of epidermal cells with multiple overlapping nuclei)

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3. Wood's Lamp Examination

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4. Scabies Preparation

1. Identify burrow - a small black dot within represents the mite
2. Apply a single drop of mineral oil to scalpel blade (keeps scrapings adherent)
3. Hold skin taut; scrape across the lesion with scalpel tip
4. Place material on slide with additional mineral oil drop; add coverslip
5. View under low power

• Mite (8-legged creature)
• Eggs (smooth ovals)
• Feces (clusters of red-brown pellets)

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5. Lice Preparation

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6. Ancillary Labs for Systemic Assessment

"Ancillary studies may also be required to assess for systemic involvement." - Tintinalli

• CT scan: assess depth of tissue involvement; gas tracking along fascial planes in necrotizing fasciitis; detect foreign bodies
• X-ray: subcutaneous gas in necrotizing fasciitis/gas gangrene
• Ultrasound: differentiate abscess from cellulitis; guide I&D; assess depth of soft tissue infection; detect foreign bodies

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7. Skin Biopsy (ED Context)

• Confirm diagnosis of TEN/SJS (frozen section if available - rapid diagnosis)
• Rule out malignancy (referral basis)
• Bullous disorders (pemphigus vs. pemphigoid - direct immunofluorescence needed)
• Vasculitis confirmation

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PART 3 - ED MANAGEMENT FRAMEWORK

STEP 1: Identify Emergencies First

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STEP 2: Systemic Corticosteroids

"Some severe widespread dermatologic syndromes, such as erythema multiforme, toxic epidermal necrolysis, and vasculitis, are best treated with systemic steroids only after consultation with a dermatologist."

• Urticaria and angioedema
• Contact/allergic dermatitis (Toxicodendron/poison ivy)
• Other allergic reactions

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STEP 3: Antihistamines - Dosing Table

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STEP 4: Topical Corticosteroids - Potency Classification

• Face, intertriginous areas, children: Low potency (Group 6-7) only
• Extremities, trunk: Intermediate (Group 3-5)
• Thick plaques (psoriasis, palms, soles): High potency (Group 1-2)
• Never use superpotent steroids on face, groin, or under occlusion chronically

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STEP 5: Topical Antibiotics

"Topical antibacterial agents are rarely useful as primary therapy for superficial bacterial infections of the skin. The exception is topical mupirocin." - Tintinalli

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STEP 6: Antipruritic (Non-Steroidal) Agents

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PART 4 - MANAGEMENT SUMMARY BY SECONDARY LESION TYPE

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• Tintinalli's Emergency Medicine: A Comprehensive Study Guide - Tables 246-1, 248-2, 248-3, 248-4, 248-5, 248-6, 248-7, 248-8, 248-9, 248-10 (Chapters 246, 248-249)
• Rosen's Emergency Medicine: Concepts and Clinical Practice - Chapter 84 (STIs), Chapter 118 (Meningococcemia)