Lichenoid eruption from Interferon Treatment of Hepatitis C

I have a female patient who is on Interferon and [another antiviral medication] for Hep C. Eight weeks into the treatment, she has a morbilliform eruption, mainly on the trunk. Somewhat pruritic. She has already tried Zyrtec, Claritin, Atarax, and Benadryl with disappointing results, as far as controlling the itch and rash. She doesn't want to stop the Interferon, and I can't blame her. No other drugs. She developed a lichenoid eruption on the upper trunk. The itch was what bothered her. Dermeleve helped her immensely.