Ethambutol Induced Lichenoid Drug Eruption: A Case Report

BACKGROUND: A rare type of cutaneous adverse drug reaction (CADR), lichenoid drug eruption (LDE), can be associated with ethambutol. CASE REPORT: A 60-year-old woman with spinal tuberculosis received multiple anti-TB medications and developed rashes after 3 months of the treatments. A skin biopsy from the posterior auricular area confirmed lichenoid dermatitis, and the Naranjo causality assessment indicated ethambutol as a probable cause of LDE in the patient. The rashes slowly improved after discontinuation of ethambutol. Unfortunately, the residual of brown hyperpigmentation on the body still persisted for over 16 months. CONCLUSION: The medications were reduced to isoniazid 300 mg/day and rifampicin 450 mg /day as planned for another 3 months. This case report points out the essentials of early recognition of ethambutol LDE by health care professionals.