A form of primary hypertrophic osteoarthropathy, a rare hereditary disorder with characteristics of digital clubbing, pachydermia and subperiosteal new bone formation associated with pain, polyarthritis, cutis verticis gyrata, seborrhea and hyperhidrosis. Three forms have been described: a complete form with pachydermia and periostitis, an incomplete form with evidence of bone abnormalities but lacking pachydermia, and a forme frusta with prominent pachydermia and minimal-to-absent skeletal changes. The disease typically begins during childhood or adolescence and may stabilize after 5-20 years of progression, or progress constantly. Mutations in the HPGD gene (4q33-q34) have been identified. The gene encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the main enzyme of prostaglandin degradation. Inherited as an autosomal recessive trait.