Drugs causing fixed drug eruptions: confirmed by provocation tests.

Drug reactions are very frequently seen by dermatologists in day to day practice. Fixed drug eruption though usually not fatal, can cause enough cosmetic embarrassment if present on the exposed part due to recurrence of the reaction on the previously affected site and residual hyperpigmentation. 40 patients of fixed drug eruption were subjected to oral provocation test with all possible drug to find out the exact causative drug(s). Co-trimoxazole was the most common cause of the fixed reaction (21). Other drug found to cause reaction include oxyphenbutazone (9). Metamezole (3), tetracycline hydrochloride (3) and piroxicam (1). Lips were most commonly involved (14). Other frequently involved sites were genitals (6), arms (5), abdomen (4), hand (4), face (4) and leg (3). To avoid false incrimination of the drugs, provocation test is the only reliable method to confirm the causative drug.