Successful treatment of psoriatic arthritis and comorbid annular atrophic lichen planus with etanercept.

Psoriasis vulgaris and lichen planus are distinct T-cell-driven inflammatory skin diseases. Both present in a variety of clinical subtypes. Mucosal or nail involvement may be present. Here, we report the rare concomitant clinical presentation of psoriatic arthritis and annular atrophic lichen planus on the trunk of a 52-year-old male patient. Treatment with sulfasalazine failed to control inflammatory activity; methotrexate and leflunomide were ceased due to side-effects. After confirmation of both diagnoses, we initiated a tumor necrosis factor (TNF)-α-directed therapy with the fusion protein etanercept resulting in significant improvement of both conditions. This case report aims to highlight the rare colocalization of psoriasis and lichen planus, the rare entity of annular atrophic lichen planus, and to discuss a possible beneficial impact of certain TNF-α inhibitors on subtypes of lichen planus.