Transient synovitis of the hip (also called “irritable hip” or “toxic synovitis”) is a common cause of sudden-onset hip pain and limping in young children. Transient synovitis is an irritation of the lining of the hip and generally occurs in children between three and 12 years old.
The exact cause is unknown. Many children develop transient synovitis following an infection with a virus (such as a cold), so one theory is that the condition is caused by a virus.
Children with transient synovitis generally report pain in one hip or leg and either limp or refuse to walk. Some children with transient synovitis have a low-grade fever.
Children with hip pain, leg pain, limping and/or refusal to walk should be evaluated by a physician right away. The physician will examine the back and legs to determine the cause of pain. Children with transient synovitis generally can’t move their hip as well on the affected side. Diagnostic tests such as x-rays and ultrasound, as well as blood tests, are used to look for more serious conditions, like infection due to bacteria in the joint or bones and childhood forms of arthritis.
For children with severe pain, fever or other concerning symptoms, it may be necessary to take fluid from the joint with a needle. The hospital laboratory can analyze this fluid to determine if bacteria or lots of white blood cells (the cells which fight infection) are present.
Irritable hip is a condition which gets better without treatment, usually within five to seven days; however symptoms last several weeks in some children. Anti-inflammatory medications such as ibuprofen may help decrease pain and shorten the length of symptoms. Children should be brought to see a doctor right away if symptoms worsen to rule out other conditions.
Children occasionally have recurrent episodes of transient synovitis.