Modafinil-induced Fixed Drug Eruption
A 29-year-old man reported itchy, painful patches of mucosal erosion with hyperpigmentation on the right half of upper lip and left half of lower lip. The patient was a student preparing for competitive examinations. He was prescribed tab modafinil 200mg in the morning by a psychiatrist to improve his daytime wakefulness and alertness for few days prior to his examinations. Within 12 h after taking a single dose of the tablet, the patient experienced numbness in his right upper lip and left lower lip. The patient discontinued the tablet. Over the next 24 h, he developed painful erosion and hyperpigmentation over the same area that persisted over the next 4-5 days []. There were no complains of fever, difficulty in breathing, or erosion or hyperpigmentation in other body parts. The patient had no history of similar complains or any allergic reaction in the past.\nA differential diagnosis of herpes zoster or an FDE was considered, and tablet acyclovir 400mg 3 times a day for 2 weeks was prescribed; however, there was no relief in the symptoms. His complete blood count was normal; the viral DNA test and Tzanck test of the oral erosions were negative for herpes simplex virus. Following this, the lesions were diagnosed as an FDE. The patient was prescribed becomethasone ointment for local application 3 times a day and tablet fexofenadine 60mg twice daily for 2 weeks. The ulcers healed completely within a week and the discoloration resolved completely over the next 4-6 weeks.