II. Pathophysiology
- Delayed Type IV Hypersensitivity Reaction
- Antibody-dependent, cell-mediated cytotoxic response
III. Epidemiology
- Of cutaneous drugs eruptions, Morbilliform rash accounts for 80% in adults and 35% in children
IV. Causes: Antimicrobials
- Antibiotics (most common)
- Sulfonamides (e.g. Bactrim) - most common
- Tetracycline - most common
- Cephalosporins
- Macrolides (e.g. Erythromycin, Clarithromycin)
- Clindamycin
- Fluoroquinolones
- Penicillins (e.g. Amoxicillin)
- Antifungals
- Miscellaneous
- Antimalarials
- Dapsone
V. Causes: Miscellaneous
- Cardiovascular agents
-
Analgesics
- Acetaminophen
- NSAIDs or Aspirin (common)
- Allopurinol
- Colchicine
- Opiates (e.g. Codeine)
- Neuropsychiatric agents
-
Antihistamines
- Hydroxyzine
- Laratodine
- Miscellaneous
VI. Risk Factors
- Immunosuppression
- Childhood Viral Infections
VII. Symptoms
- Lesion with pruritic or burning pain
- Lesion timing after initial exposure
- Onset 4 to 21 days after starting medication
- Lesion timing after subsequent exposure
- Onset within 0.5 to 8 hours (up to 16 hours) after medication ingestion
- Lesions recur at same site on reexposure to drug
- Systemic Symptoms are rare
- Fever, malaise and Nausea may be seen with Drug-Induced Bullous Disease
VIII. Signs
- Lesion onset on the trunk and spreads peripherally
- Lesion distribution
- Symmetric involvement on trunk and extremities (especially dependent, warm areas)
- Face or ears
- Genital region
- Sacral area
- Hands or feet
- Spares mucous membranes
- Lesion characteristics
- Coloration
- Pink to dark red
- Maculopapular Rash with Annular Lesions
- Round erythematous patch with sharp borders
- May also present as bullae or ulcers
- Hyperpigmentation may occur on healing after withdrawal of causative agent
- Coloration
IX. Management
- Withdraw suspected medication
- Consider Corticosteroids (topical or systemic)
- Consider Antihistamine for Pruritus
- Observe open lesions for secondary infection
X. Course
- Resolves in 7-10 days after medication stopped