Fixed drug reaction

Fixed drug reactions are common and so named because they recur at the same site with each exposure to a particular medication. Medications inducing fixed drug eruptions are usually those taken intermittently.

Signs and symptoms
A painful and itchy reddish/purple patch of skin that occurs in the same location with repeated exposures to the causative drug is the classic presentation of a fixed drug reaction. The lips, genitals, and hands are often involved.

Cause
Medications that are commonly implicated as a cause of fixed drug eruptions include the following:
 * Cetirizine
 * Ciprofloxacin
 * Clarithromycin
 * Cotrimoxazole
 * Doxycycline
 * Fluconazole
 * NSAIDs (e.g., ibuprofen, etoricoxib, naproxen)
 * Phenytoin
 * Pseudoephedrine
 * Trimethoprim