Pustular osteoarthropathy and its differential diagnosis.

A combination of costo-sterno-clavicular hyperostosis and palmo-plantar pustulosis, sometimes with hyperostotic spondylosis and spondylarthritis, is called pustular osteoarthropathy. In the Western hemisphere 40 cases have been reported and in the Far East the condition occurs more commonly. Five cases are described. Diagnosis is difficult because the skin lesions can occur before the costo-sterno-clavicular hyperostoses. The clinical condition is discussed together with the differential diagnosis. Pustular osteoarthropathy seems to be an enthesopathy and the palmoplantar pustulosis is interpreted as a form of psoriasis.