Fixed drug eruption (FDE) is a well-defined, circular, hyperpigmented plaque that recurs as one or a few lesions always in fixed locations upon ingestion of a drug. FDE commonly occurs on the genitals, lips, trunk, and hands. Although the lesions are distinctive, the diagnosis of FDE often is missed because it shares none of the characteristics of more common morbilliform drug rashes. The diagnosis can be confirmed by histopathologic examination of a small punch biopsy specimen. Drug avoidance is the mainstay of treatment, and antihistamines can reduce associated pruritus. Raising awareness of this condition will increase the likelihood of prompt diagnosis leading to resolution within days to weeks after the offending drug is discontinued.
Signs and symptoms
A painful and itchy reddish/purple patch of skin that occurs in the same location with repeated exposures to the culprit drug is the classic presentation of a fixed drug reaction. The lips, genitals, and hands are often involved.
Medications that are commonly implicated as a cause of fixed drug eruptions include the following:
NSAIDs (e.g., ibuprofen)