Exacerbation of pityriasis rubra pilaris under efalizumab therapy

A 60-year-old woman, diagnosed as having psoriasis vulgaris in 2004 and unresponsive to standard therapies, received weekly subcutaneous injections with efalizumab. Within 9 weeks of treatment a massive aggravation of skin lesions occurred with widespread orange-tinged erythroderma, islands of normal skin on the back and the inner side of the forearms and palmoplantar hyperkeratosis. A biopsy confirmed the clinical diagnosis of pityriasis rubra pilaris. After discontinuation of efalizumab and treatment with oral corticosteroids, acitretin (30 mg/day) and PUVA therapy, the skin lesions continuously improved. Efalizumab, a fully humanized monoclonal antibody against CD11a, inhibits various T cell processes important in the pathogenesis of psoriasis. Efalizumab has been approved for the treatment of moderate to severe psoriasis, but there are no reports in the literature on the use of efalizumab for pityriasis rubra pilaris.