| SJS/TEN | - Sheet-like skin and mucosal loss
- SJS <10% BSA, Overlap 10-30%, TEN >30% BSA
- Incidence: 1-2 affected per million
- Slightly more common in females. 100X more common in HIV
- Most common culprits:
- Sulfonamides: cotrimoxazole
- Beta-lactam: penicillins, cephalosporins
- Anti-convulsants: lamotrigine, carbamazepine, phenytoin, phenobarbitone
- Allopurinol
- Nevirapine (non-nucleoside reverse transcriptase inhibitor)
- Nonsteroidal anti-inflammatory drugs (NSAIDs) (oxicam type mainly)
- Usually preceded by flu-like illness: aches, pains, fever, sore throat, conjunctivitis
- Pt typically with marked skin pain with a dusky rash
- Mortality rate 10% SJS, 30% TEN; can be more accurately predicted with SCORTEN score
| - Cessation of causative/suspect drugs - consider burns unit admission for wound care management
- Pain management
- Early involvement burn, derm, and ophthalmology teams
- Systemic steroids of unclear efficacy given wound care & infection concerns, often avoided unless due to ICI and highly debatable. Mainstay of treatment is etanercept (managed by derm)
- Heated room 30-32 degrees Celsius
- Consider alternative diagnoses (DRESS, AGEP)
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| Prickly heat rash | - Heat causes exocrine sweat duct obstruction, resulting in raised, itchy rash. There may be a component of sweat duct obstruction by extracellular polysaccharide substance (EPS) produced by Staphylococcus epidermidis in the pathophysiology.
- Associated with former heating pad sites, abundance of blankets
| - Take cool baths or showers; tap dry; use cold compresses
- Wear loose cotton clothing
- Use lightweight bedding
- Drink plenty of fluid to avoid dehydration
- Self-limiting condition
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| Cutaneous Small Vessel Vasculitis | - Inflamed small blood vessels due to infiltration of neutrophils into blood vessel walls
- Rash caused by small areas of hemorrhage, resulting in purple red lesions (palpable purpura)
- Punch biopsy for H&E and direct immunofluorescence to confirm diagnosis (referred to histologically as leukocytoclastic vasculitis)
- Frequently occurs in association w/ systemic dx: infection, SLE, RA, Sjogren, malignancy, drug-induced
- Many cases are idiopathic
| - Early involvement of dermatology: after confirmation via punch biopsy, treat most likely underlying source of disease - tx often involves systemic corticosteroid if severe or systemic involvement
- Removal of offending drugs, antihistamines, and NSAIDs is often appropriate for isolated cutaneous disease
- Important to rule out systemic vasculitis (specifically IgA vasculitis, and monitor kidney function)
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| DRESS - Drug Reaction with Eosinophilia and Systemic Symptoms | RegiSCAR is a validated scoring system for potential cases, requires at least 3 of the following: - Prolonged resolution time (>15 days)
- Atypical Lymphocytes
- Acute skin rash
- Fever above 38.5C
- Enlarged lymph nodes at two sites
- Involvement of at least one internal organ
- Eosinophilia
- Important to have absence of alternative diagnoses too
- Clinical presentation is variable, but may include morbilliform drug reaction +/- erythroderma, facial swelling +/-mucosal involvement
- Causative agents: allopurinol (esp together with thiazide), sulfa drugs, carbamazepine, phenobarbital, phenytoin, iodinated contrast
- Onset ~ 2-6 weeks of inciting drug
- 5% mortality rate
| - Withdraw all suspected meds
- Dermatology consult
- Systemic corticosteroids with slow prolonged taper for severe disease
- Supportive tx with unscented emollients, topical corticosteroids for mild disease
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| Pyoderma gangrenosum | - Rapidly enlarging, painful ulcer, autoinflammatory etiology
- Full thickness with purple/blue undermined borders
- 50% cases have an underlying disease pathology, ex: IBD (UC>Crohn's), RA, hematologic malignancies, solid malignancies, idiopathic
| - Mostly non-surgical, though skin grafting may be necessary after active phase
- Potent topical steroid for local disease
- Large ulcers may require oral steroids, anti-TNF agents (adalimumab, infliximab, etanercept), dapsone, mycophenolate, anti-IL-1s, anti-IL-23s, IVIG
- Avoidance of local trauma
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| Sweet Syndrome | - Presentation: Tender erythematous plaques/nodules; upper extremities, trunk, head/neck; fever common
- Criteria: Both major criteria required:
- Abrupt onset of tender erythematous plaques/nodules
- Dense neutrophilic infiltrate without vasculitis
Plus ≥2 minor criteria: - Fever >38°C
- Associated condition (infection, malignancy, drug, pregnancy)
- Excellent response to corticosteroids
- Abnormal labs (≥3 of: ESR >20, elevated CRP, leukocytosis >8,000, neutrophils >70%)
- Subtypes: Classic (30-53%), malignancy-associated (34-44%; AML/MDS most common), drug-induced (12-29%; G-CSF most common)
- Onset: Abrupt; 1-3 weeks post-infection in classic form
- Recurrence: ~25-33%
| - Dermatology consult for biopsy
- Systemic corticosteroids (prednisone 0.5-1 mg/kg/day); alternatives: potassium iodide, colchicine, dapsone; withdraw suspected drugs; treat underlying malignancy
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| Toxic shock syndrome | - Pathophys: localized staph infection → bacterial exotoxins trigger massive cytokine release, producing rash (sunburn appearance), fever, hypotension
- Initial phase: diffuse macular rash, "sunburn appearance", fever, multiorgan abnormalities
- Secondary phase: 1-2 wks later: shedding skin in large sheets
- Prior toxic shock is a risk factor for recurrence
- Majority of cases are surprisingly in healthy adults aged 20-50
- Complications: TSS is characterized by rapid progression to multi-organ failure that can occur within 8-12 hours of symptom onset
| - Peripheral blood cultures can be obtained (will not always be positive)
- Aggressive source control is essential (removal of foreign body, etc)
- Typically, will use penicillinase-resistant penicillin (e.g., nafcillin, oxacillin), cephalosporin, or vancomycin (in MRSA-prevalent areas or penicillin allergy) + clindamycin or linezolid to suppress toxin production
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| Cutaneous blastomycosis | - Skin lesions starting as papules, or pustules. Over course of weeks, develop into ulcerated/verrucous plaques
- Screen all for HIV
- When the infection spreads and skin becomes involved, spontaneous resolution does not occur and treatment is necessary.
| - Treat underlying immunosuppressive condition, for example, HIV
- ID consult warranted: skin involvement necessitates treatment bc spontaneous resolution does not occur: mild-moderate disease: treat with itraconazole, severe disease: treat with amphotericin B
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| RMSF: Rocky Mountain Spotted Fever | - The rash first spreads centrifugally from the wrists and ankles to the palms and soles, then spreads centripetally to the arms, legs, and trunk; face typically rash-free in beginning of course. Starts as red macules, then becomes papular and petechial
- The absence of rash should not preclude consideration of RMSF as 9-12% of patients never develop a rash
- Can cause multiorgan failure
| - Tx: doxycycline 100 mg BID, even in pregnant females (requires ID consult)
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| MIRM – Mycoplasma induced rash and mucositis | - Affects younger demographic than SJS/TEN
- Causative agent = mycoplasma pneumoniae
- Predominant mucosal & ocular features, with fewer cutaneous features than SJS/TEN
MIRM characteristics: - <10% BSA with detachment
- >2 mucosal sites involved
- Few cutaneous vesiculobullous lesions
- Atypical pneumonia present
- Labs: increase in M. Pneumoniae IgM antibodies, M. Pneumoniae in oropharyngeal or bullae cultures or PCR, and/or serial cold agglutinins
- PCR and IgM serology cannot reliably differentiate infection from carriage
| - Early Optho and Derm involvement (esp since SJS/TEN should be ruled out)
- Ophthalmology may recommend the following: conservative management with preservative-free artificial tears and lubricants as first-line (topical antibiotics such as moxifloxacin or erythromycin ointment are used to prevent secondary infection), with topical corticosteroids guided by ophthalmology
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| Acute Generalized Exanthematous Pustulosis (AGEP) | - Numerous small, sterile, non-follicular pustules on erythematous base
- Intertriginous areas first → trunk and extremities
- High fever (>38°C) in ~50%
- Pruritus
- Leukocytosis with neutrophilia, eosinophilia
- Onset: 2-11 days (median 3 days)
- Most common precipitants: antibiotics (beta-lactams 42%), calcium channel blockers, anticonvulsants
| - Discontinue offending agent
- Topical corticosteroids (first line)
- Systemic corticosteroids for severe cases
- Supportive care
- Self-limited, median resolution 8 days
- Mortality 3.5%
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