Patch tests in adverse cutaneous drug reaction

Twenty-one patients with history of adverse cutaneous drug reaction were patch tested with 23 commonly used drugs in 5% concentration in petrolatum. Nine patients (42.85%) tested were positive to the incriminated drugs while 3 (14.28%) showed positive reactions to other drugs. Highest positivity (50%) was seen in maculo-popular cases while Stevens-Johnson syndrome and exfoliative dermatitis patients showed negative results.