Pachydermoperiostosis (PDP), also known as Touraine-Solente-Golé syndrome and primary hypertrophic osteoarthropathy, is a very rare genodermatosis marked by facial skin thickening, furrowing and oiliness (pachydermia), digital clubbing, and periostosis. Inheritance is either autosomal dominant (more common) with incomplete penetrance or autosomal recessive. The disease is markedly more common in males than females, with a peak age of onset occurring in adolescence. PDP has 3 clinical phenotypes: a complete form (periostosis and pachydermia), an incomplete form (without pachydermia), and a forme fruste (pachydermia with minimal skeletal changes). The complete phenotype is characterized by progressive pachydermia, periosteal bone formation in the long bones, digital clubbing, and painful joint swelling. Joint involvement may show hydrarthrosis or hemarthrosis. Associated skin findings include seborrhea, hyperhidrosis of the palms and soles, acne, blepharoptosis, eczema, and cutis verticis gyrata. Skin and bone manifestations tend to progress for 5–20 years before stabilizing.
Bulbous swelling of the distal phalanx of the fingers that stops abruptly at the distal interphalangeal joint. Note the associated onychodystrophy and increased transverse nail curvature.