[Pachydermodactyly]

The differential diagnosis of swelling of the small finger joints is broad. We report on two young men presenting with progressive painless swelling of the proximal interphalangeal (PIP) joints where the physical examination was otherwise inconspicuous. Laboratory investigations including auto- antibodies were all normal, x-rays and magnetic resonance imaging (MRI) revealed no joint pathologies but only increased skin thickening. Skin biopsy demonstrated hyperkeratosis and acanthosis without tissue inflammation. We thus diagnosed pachydermodactyly in both cases. This rare disease predominantly affects young males, can affect one or both hands and is often associated with mechanical stress due to repetitive movements in patients with obsessive-compulsive disorders. Occupational exposure by monotonous actions (e.g. poultry processing) may also be a cause. A specific therapy is unnecessary in most cases but may include intralesional steroid administration or surgical resection. Cessation of mechanical stress can significantly improve pachydermodactyly.