Clinical Profile of Patients with Lichenoid Drug Eruption: A Observational Study.

Background: Lichenoid drug eruption (LDE) is an uncommon cutaneous adverse drug reaction, where a variety of drugs used in day-to-day clinical practice have been implicated. Objective: To describe the clinico-demographic characteristics of patients with LDE and to identify the most likely drugs involved. Methods: In this prospective, observational study, consecutive patients with LDE presenting to the dermatology department of a tertiary teaching hospital were included. The clinico-demographic profile of patients with LDE and implicated drugs was noted. Treatment of drug reaction along with outcome was also documented. Naranjo adverse drug reaction probability scale was used for causality assessment of the drug reactions. A thorough literature review on LDE was also undertaken due to the paucity of existing literature. Results: A total of 15 patients (11 males and 4 females) with LDE were evaluated. Their age ranged from 37 to 61 years, with a mean of 51.53 ± 7.59 years. Anti-hypertensive medications (40%) were the most common culprit agent, followed by antitubercular drugs (33.4%), anti-diabetic agents (13.3%), and others (13.3%). The latent period (time from drug initiation to the appearance of a cutaneous eruption) varied from 15 days to 6 months (mean 2.2 months). Cutaneous involvement was generalized in 73.4% and photo-distributed lesions in 26.6%. Drug provocation test was done to identify the culprit drug. According to the Naranjo adverse drug reaction probability scale, one-third of LDEs were "definite," whereas two-thirds were designated as "probable." Conclusion: LDE is more common in the elderly population. The latent period is comparatively longer in LDE than in other common drug reactions. Prompt recognition and withdrawal of suspected drug are essential to minimize disease morbidity.