Lichenoid Reaction Caused by Antihistamines and Corticosteroids.

Lichenoid reaction (LR) is clinically and histopathologically similar to lichen planus (LP), which involves the skin and mucous membrane. LR has identifiable etiology and can be triggered by systemic drug exposure or any other agents. LR occurs in all racial groups and is predominantly observed in young adults aged 20-40 years, but can occur in any age group. Typically, the clinical manifestation of LR is an itchy rash of small (±3-5 mm) shiny, raised, reddish-purple papules. The rash appears suddenly and commonly affects the anterior surface of the arm and hand and the back part of the body. We report a rare case of LR to antihistamines (cetirizine, loratadine) and corticosteroid (methylprednisolone): an adult female 32-year-old patient, with a chief complaint of burning sensation, a few small rashes and itching on the anterior surface of the arm after eating seafood and eggs 7 days prior to admission. From the detailed and chronologic anamnesis of her dietary habits, routine use of drugs and oral hygiene, and from the histopathological results, we concluded the patient has lichenoid reaction caused by drugs (antihistamines and corticosteroids).