Fixed Drug Eruption

Aka: Fixed Drug Eruption, Morbilliform Drug Reaction

1. See Also
   1. Adverse Drug Reaction
   2. Life-Threatening Drug-Induced Rashes
   3. Hypersensitivity Reaction
   4. Anaphylaxis
   5. Penicillin Allergy
   6. Gell and Coombs Classification
2. Pathophysiology
   1. Antibody-dependent, cell-mediated cytotoxic response
3. Causes: Antimicrobials
   1. Antibiotics
      1. Sulfonamides (e.g. Bactrim) - most common
      2. Tetracycline - most common
      3. Cephalosporins
      4. Macrolides (e.g. Erythromycin, Clarithromycin)
      5. Clindamycin
      6. Fluoroquinolones
      7. Penicillins (e.g. Amoxicillin)
   2. Antifungals
      1. Fluconazole
      2. Ketoconazole
      3. Griseofulvin
   3. Miscellaneous
      1. Antimalarials
      2. Dapsone
4. Causes: Miscellaneous
   1. Cardiovascular agents
      1. Beta Blockers
      2. ACE Inhibitors
      3. Flecainide
   2. Analgesics
      1. Acetaminophen
      2. NSAIDs or Aspirin (common)
      3. Allopurinol
      4. Colchicine
      5. Opiates (e.g. Codeine)
   3. Neuropsychiatric agents
      1. Barbiturates
      2. Gabapentin
      3. Carbamazepine
      4. Lamotrigine
      5. Benzodiazepines
      6. Lithium
   4. Antihistamines
      1. Hydroxyzine
      2. Laratodine
   5. Miscellaneous
      1. Finasteride
5. Symptoms
   1. Lesion with pruritic or burning pain
   2. Lesion timing after initial exposure
      1. Onset within days to typically 1-2 weeks of medication use
   3. Lesion timing after subsequent exposure
      1. Onset within 0.5 to 8 hours (up to 16 hours) after medication ingestion
      2. Lesions recur at same site on reexposure to drug
6. Signs
   1. Lesion distribution
      1. Symmetric involvement on trunk and extremities (especially dependent, warm areas)
      2. Face or ears
      3. Genital region
      4. Sacral area
      5. Hands or feet
      6. Spares mucous membranes
   2. Lesion characteristics
      1. Coloration
         1. Pink to dark red
      2. Annular Lesions
         1. Round erythematous patch with sharp borders
      3. May also present as bullae or ulcers
      4. Hyperpigmentation may occur on healing after withdrawal of causative agent
7. Management
   1. Withdraw suspected medication
   2. Consider Corticosteroids (topical or systemic)
   3. Consider Antihistamine for Pruritus
   4. Observe open lesions for secondary infection
8. Course
   1. Resolves in 7-10 days after medication stopped
9. Complications
   1. Postinflammatory Hyperpigmentation
10. References
    1. Crowson (2003) Am J Clin Dermatol 4:407-28 [PubMed]
    2. Trayes (2018) Am Fam Physician 98(5): 283-91 [PubMed]