What is Toxic Synovitis

Toxic synovitis is a temporary form of arthritis that causes pain in the hip. This condition almost always develops before puberty. Toxic synovitis is also known as transient synovitis.

What are the causes?

The cause of this condition is not known. This condition often develops after a viral infection.

What increases the risk?

This condition is more likely to develop in:

• Males.
• Children who are 3–10 years of age.

What are the signs or symptoms?

Symptoms of this condition include:

• Hip pain. Usually, the pain is felt only on one side.
• Pain in the front and middle of the thigh.
• Knee pain.
• Low-grade fever.
• Limping.
• Refusal to walk.
• Crying and abnormal crawling in babies.

Symptoms are usually mild and go away within 1–2 weeks. Sometimes, however, symptoms can last for about a month.

How is this diagnosed?

This condition is diagnosed when other, more serious conditions have been ruled out with tests. Tests may include:

• Blood tests.
• Urine tests.
• X-rays.
• An ultrasound.
• MRI.
• Hip joint fluid tests.

How is this treated?

This condition may be treated with:

• Resting in bed (bed rest) for several days.
• Limiting activities that cause pain.
• Massage of the hip.
• Medicines to reduce inflammation
• Medicines for pain.

Follow these instructions at home:

• Allow your child to rest. Your child should not return to his or her regular activities until the pain and the limp have gone away. Ask your child’s health care provider what activities are safe for your child.
• Have your child avoid using the affected leg to support his or her body weight until the pain and the limp have gone away.
• Give over-the-counter and prescription medicines only as directed by your child’s health care provider.
• Keep all follow-up visits as directed by your health care provider. This is important. Your child may need X-rays 6 months after the problem first developed.

Contact a health care provider if:

• Your child’s hip pain or limping lasts for more than two weeks.
• Your child’s pain is not controlled with medicines.
• Your child’s pain gets worse.
• Your child develops pain in other joints.
• Your child develops redness or swelling over the hip joint.
• Your child has a fever.

Get help right away if:

• Your child develops severe pain.
• Your child cannot walk.
• Your child who is younger than 3 months has a temperature of 100°F (38°C) or higher.