Toxic Synovitis

Overview, Causes, & Risk Factors

Toxic synovitis is a frequent cause of limping with hip pain in children. It occurs in children prior to the onset of puberty and is a transient arthritis of the hip that usually resolves on its own. Its cause in not known but boys are affected more frequently than girls (approximately 4 to 1).

Symptoms are usually mild and generally include hip pain and a slight limp. The hip pain almost always involves only one side (unilateral). A low grade fever (usually less than 101 degrees) may be an early symptom. Aside from the hip discomfort, the child does not usually appear ill.

Toxic synovitis is a diagnosis of exclusion, which means that it is diagnosed when other, more serious conditions, have been ruled out. In children there are three potentially serious diseases that can cause hip pain and limp: septic hip, slipped capital femoral epiphysis, and Legg-Calve-Perthes disease. Once these other diagnoses have been excluded, then the diagnosis of toxic synovitis (which is the most common of all these diseases) is usually made.