Development of psoriasis scalp with alopecia during treatment of Crohn's disease with infliximab and rapid response to both diseases to ustekinumab.

Anti tumor necrosis factor antibodies are used to treat both psoriasis and inflammatory bowel disease. Several paradoxical cases of psoriatic skin lesions induced by tumor necrosis factor antagonist therapy have been described in IBD patients in the recent years. Ustekinumab, a fully human anti-interleukin-12/-23 monoclonal antibody, is the first drug of a new class of biologic therapy approved for the treatment of moderate to severe plaque psoriasis. Data on the efficacy of ustekinumab in patients with moderate-to-severe Crohn's disease, especially in patients previously treated with infliximab, have been recently published. We report about the effectiveness of ustekinumab in the treatment of both severe scalp psoriasis lesions with alopecia and active Crohn's disease.