Background and Objective: FIXED drug eruption (FDE) is one kind of drug rashes that is characterized by re-appearance of the lesions on the same sites after re-exposure to the causative drug. This study was performed to evaluate the epidemiologic characteristics of FDE.
Materials and Methods: This descriptive study was done on a series of 100FDE cases, whom were admitted at the outpatient dermatology clinic of Hazrat-e-Rasoul Hospital over a six-year period. The primary diagnosis of FDE was suggested according to clinical findings including a remaining hyperpigmentation at the site of healed skin lesion(s). Oral challenge test with a single low dose administration of the suspected drug was used to confinn the diagnosis. Recurrence of the lesion(s) at the same body area(s) was considered as positive result.
Results: Most commonly causative agents were co-trimoxazole and codein, which were found in 88% and 3% FDE cases; respectively. The most common site of involvement was penile glans in 57.7% of male patients and trunk in 48.3% of females. In one patient, reaction to multiple drugs including co-trimoxazole, codein and tetracycline was observed and after re-challenge with each drug, re-appearance of the skin lesion at the same site was evident. Several patients reported concomitant acetaminophen intake, but there was no reaction to that drug. Conclusion: Co-trimoxazole is the most common cause of FDE.