PDP is the primary form of hypertrophic osteoarthropathy (HOA)
which should be distinguished from the secondary form of HOA,
which is much more frequent and mostly associated with severe pulmonary disease, bronchogenic carcinoma, lung empyema, bronchiectasis, congenital heart disease, and thyroid or GI malignancy 1. It
was first described by Friedreich2 in 1868, who called it ‘Hyperostosis
of the entire skeleton’. In 1907, Unna named the term ‘cutis verticis
gyrate’ for thick, transversely folded skin of scalp and forehead.