Drugs causing fixed eruptions: a study of 450 cases

Drug eruptions are among the most common cutaneous disorders encountered by the dermatologist. Some drug eruptions, although trivial, may cause cosmetic embarrassment and fixed drug eruption (FDE) is one of them. The diagnostic hallmark is its recurrence at previously affected sites.

We evaluated 450 FDE patients to determine the causative drugs.

The ratio of men to women was 1:1.1. The main presentation of FDE was circular hyperpigmented lesion. Less commonly FDE presented as: nonpigmenting erythema, urticaria, dermatitis, periorbital or generalized hypermelanosis. Occasionally FDE mimicked lichen planus, erythema multiforme, Stevens-Johnson syndrome, paronychia, cheilitis, psoriasis, housewife's dermatitis, melasma, lichen planus actinicus, discoid lupus erythematosus, erythema annulare centrifugum, pemphigus vulgaris, chilblains, pityriasis rosea and vulval or perianal hypermelanosis. Cotrimoxazole was the most common cause of FDE. Other drugs incriminated were tetracycline, metamizole, phenylbutazone, paracetamol, acetylsalicylic acid, mefenamic acid, metronidazole, tinidazole, chlormezanone, amoxycillin, ampicillin, erythromycin, belladonna, griseofulvin, phenobarbitone, diclofenac sodium, indomethacin, ibuprofen, diflunisal, pyrantel pamoate, clindamycin, allopurinol, orphenadrine, and albendazole.

Cotrimoxazole was the most common cause of FDE, whereas FDE with diclofenac sodium, pyrantel pamoate, clindamycin, and albendazole were reported for the first time. FDE may have multiform presentations.