Fixed drug eruption

• a drug eruption that occurs at the same site(s) each time the offending drug is taken (1)
  • causes include:
    • phenolphthalein (present in many over the counter laxatives)
    • barbiturates
    • NSAIDs
    • codeine
    • paracetamol
    • tetracyclines
    • chlordiazepoxide
    • sulphonamides (includes sulphonamide antibiotics, sulphonylureas, thiazide diuretics)
  • lesions:
    • usually appear within a couple of days to weeks after drug ingestion and resolves with the withdrawal of the offending drug
    • often painful, pruritic or burning
    • appear as clearly demarcated oval or round erythematous plaques
    • become violaceous after 1-2 days
    • typically 1-3 lesions
    • common sites - hands, feet, glans penis, lips, sacral skin
    • lesions fade after about 1 week and leave a hyperpigmented patch that may last for several months
    • rare presentations include periorbital or generalized hypermelanosis (1)

Drug rechallenge can be used to find out the causative drug. Patch testing and intradermal skin testing can also be used in some patients (1)

Management options include

• identifying and discontinuing the offending drug
• systemic antihistamines with topical corticosteroids for the lesions
• systemic corticosteroids – for extensive lesions with bullae (1)

Reference:

• (1) Goksugur N, Parlak AH. Photo Quiz - Itchy and Painful Ulceration on the Penis. AFP 2006;73(1)