Oral mucosal fixed drug eruption: Characteristics and differential diagnosis

Background: Little is known about the characteristic features of oral mucosal fixed drug eruption (FDE). Objective: To present the clinical highlights and the differential diagnosis of oral mucosal FDE in a relatively large group of patients from Turkey. Methods: This was a methodological, retrospective, cross-sectional study of 61 patients with oral mucosal FDE. The causative drug was established mainly by oral provocation test. Results: The age range of 61 patients (38 females, 23 males) was 7 to 62 years. Naproxen and cotrimoxazole were the main inducers. Fourteen patients (23%) had a solitary oral lesion predominantly located on the dorsum of the tongue, or on the hard palate, the former statistically significantly associated with cotrimoxazole. Bullous/erosive (n = 47), aphthous (n = 12), and erythematous (n = 2) morphology were observed. A considerable number of patients were referred with a prior clinical diagnosis of herpes simplex and Behcet's disease; some of them were already receiving long-term treatment with acyclovir and colchicine, respectively. Limitations: The main limitation of the present study resides in its retrospective design. Conclusions: Isolated oral lesions, aphthous lesions, severe bullous/erosive lesions, and the absence of residual pigmentation are the main features that may cause difficulties in the differential diagnosis. It is important to differentiate dysmenorrhea-related monthly attacks of oral FDE in female patients caused by nonsteroidal anti-inflammatory drugs from menstruation-triggered attacks of herpes simplex infection, and isolated orogenital aphthous FDE from Behcet's disease, especially in countries with a high frequency of the disease in order to prevent irrelevant therapies.