Presence of lichen planus during a course of interferon alpha-2a therapy for a viral chronic C hepatitis.

We present the case of a 66-year-old woman with a diagnosis of chronic active viral C hepatitis, for whom a course of interferon alpha-2A was prescribed at a dose of 4.5 MU per day for a 2 month period, followed by the same dose on alternate days for 4 months. After completion of a month of therapy, the patient presented with painful oral lesions that made normal oral food intake impossible. These lesions persisted, in spite of withdrawal of interferon therapy. Intraoral examination revealed erosive intraoral lesions in both yugal mucosae, the upper vestibular gum, the floor of the mouth, the ventral region of the tongue, and the lower lip. A diagnosis of erosive lichen planus induced by interferon therapy was established. The prescribed treatment was 0.1% triamcinolone acetonide in orabase applied 3 times a day for 4 weeks. Following the therapeutical course, the erosive lesions disappeared, and the symptoms stopped, although the reticular lesions remained visible.