Atypical Psoriatic Arthritis Presenting as Presumed Septic Monoarticular Arthritis.

The authors present a case of monoarticular psoriatic arthritis affecting the knee of a woman with no previously identified manifestations of psoriasis. At time of symptom onset, joint aspirates were initially sterile with predominantly neutrophilic leukocytosis; however, repeat aspiration and culture was positive for Candida parapsilosis. Despite appropriate antifungal treatment, symptoms continued to worsen and other large joint manifestations including the contralateral elbow raised suspicions for alternative etiology. Ultimately new onset skin excoriations on the palms suggested psoriatic arthritis, which was subsequently treated with immunosuppressive therapy.