Rarely, tumor necrosis factor (TNF)-α antagonist therapy has been associated with de novo psoriasiform eruptions. This is unusual in that these same drugs are used to treat psoriasis. The majority of these cases involve the palms and soles, yet palmoplantar pustular psoriasis represents only 1.7% of all cases of psoriasis. Keratoderma blenorrhagicum is a psoriasiform rash that occurs primarily on the palms and soles in some patients with reactive arthritis. It is grossly and histologically indistinguishable from pustular psoriasis. Chlamydia trachomatis is a common etiologic agent for reactive arthritis, and in vitro studies have demonstrated that chlamydial replication is inversely proportional to TNF-alpha levels. We present three patients taking TNF-α antagonists who developed such lesions and who were found to be positive for C. trachomatis DNA in the affected skin. We propose that these psoriasiform lesions may not be psoriasis, but rather keratoderma blenorrhagicum.