Toxic synovitis is an inflammatory arthritis in the hip. It's the most common form of arthritis in children. Toxic synovitis comes on suddenly but goes away in a few days with no lasting effects. It's also called transient synovitis.
It usually occurs in children 3 to 10 years of age after a viral infection. It may be related to the body’s immune response to the virus. Many viral illnesses can trigger this response, including the common cold, stomach flu, chickenpox, mumps, rubella, and other contagious diseases.
Toxic synovitis usually causes a limp and hip, thigh, or knee pain. Usually only one hip is affected. But sometimes both hips are involved. There is usually no fever, redness, or swelling of the joint. It is not a contagious disease. The healthcare provider may order blood tests or X-rays to rule out other causes of hip pain.
Walking will hurt for the next few days. Your child should stay home and rest as long as he or she has a limp.
You may give over-the-counter medicine as directed based on age and weight for fever, fussiness, or discomfort. In infants older than 6 months of age, you may give a non-steroidal anti-inflammatory medicine such as ibuprofen. This medicine may help better than acetaminophen. Talk with your child's healthcare provider before giving these medicines if your child has chronic liver or kidney disease. Also talk with the provider if your child has had a stomach ulcer or digestive bleeding. Never give aspirin to a child under 18 years of age who is ill with a fever. It may cause severe disease (Reye syndrome) or death.
Follow up with your child's healthcare provider, or as advised.
When to seek medical advice
Call your child's healthcare provider right away if any of these occur:
Also call the provider right away if
Your child is 3 months old or younger and has a fever of 100.4°F (38°C) or higher. Get medical care right away. Fever in a young baby can be a sign of a dangerous infection.
Your child is of any age and has repeated fevers above 104°F (40°C)
Your child is younger than 2 years of age and a fever of 100.4°F (38°C) continues for more than 1 day
Your child is 2 years old or older and a fever of 100.4°F (38°C) continues for more than 3 days
Your baby looks very ill, is fussy, or cries and cannot be soothed
Your child looks ill even after the fever has gone down