[Activation of psoriasis in patients undergoing treatment with interferon-beta].

Psoriasis is a chronic, inflammatory skin disorder that is induced and aggravated by a number of endogenous and exogenous factors. Traditionally lithium, beta blockers, NSAIDs, ACE inhibitors and antimalarials have been associated with psoriasis, but interferon can also be a triggering factor. We present two patients with multiple sclerosis who suffered from activation of psoriasis in relation to interferon-beta treatment. In one of the patients, psoriasiform injection site lesions persisted six years after termination of the interferon treatment.