Hypertrophic Osteoarthropathy

Hypertrophic osteoarthropathy (HOA) consists of digital clubbing, increased periosteal activity of the tubular bones, arthralgias, and joint effusion. It is characterized by abnormal proliferation of the skin, soft tissues, and osseous tissues in the distal parts of extremities.  There are 2 forms of the disease, primary and secondary. Primary HOA (PHO), also called pachydermoperiostosis, comprises digital clubbing, periostosis, and pachydermia and is a rare genetic disease. At the same time, secondary hypertrophic osteoarthropathy is associated with a variety of pulmonary, cardiac, and other conditions. Clubbing is among the oldest signs in clinical medicine, first described in a man with curved fingernails and empyema by Hippocrates (460 BC-370 BC). Friedreich was the first to scientifically describe primary hypertrophic osteoarthropathy in 1868 as "hyperostosis of the entire skeleton" in 2 affected brothers. In 1935, Touraine, Solente, and Gole distinguished PHO as the primary form of HOA and distinct from HOA associated with an underlying disease like pulmonary or cardiac disease.