Irritable hip results from hip joint inflammation. It is a common cause of hip pain and limping in children aged 10 years or younger.
Doctors refer to irritable hip as acute transient synovitis or toxic synovitis. It is
The tissues around the hip joint swell, usually in only one hip. Pain may spread from the hip to the groin, thigh, and knee.
The symptoms may cause alarm and discomfort, but irritable hip is a mild condition that usually lasts up to 2 weeks.
In this article, we look at the symptoms and causes of irritable hip, as well as the treatments.
Irritable hip is a transient condition in children that causes pain and a limp.
The pain ranges from mild to severe and tends to start suddenly. It usually occurs on one side of the hip, but it can affect the hip, groin, thigh, and knee on the affected side.
Children may develop a limp, and babies may crawl or cry in an unusual way because of the pain. This may be more noticeable while changing diapers.
A slight fever sometimes occurs, but this is less common. If a child has a fever of above 101ºF, they more likely have a different health problem that could be more serious.
In acute transient synovitis, inflammation occurs in the synovial membrane that surrounds the hip. The underlying reason for this is not clear.
Possible explanations include:
A viral infection
The inflammation in the hip may be an allergic reaction that occurs when the immune system responds to infection elsewhere in the body.
A fall or another injury
A child may experience physical trauma before the symptoms of irritable hip become clear.
The doctor, usually a primary care physician, will ask the child, parent, or caregiver about symptoms, then perform a physical examination.
They may also order an imaging scan, such as an X-ray, or a blood test to detect infection.
Some conditions cause symptoms similar to those of irritable hip, including:
- Perthes disease: This can damage the head of the femur, or thighbone, by interrupting the blood supply to the hip.
- Fracture or contusion: Either of these injuries to the hip can cause it to flare up.
- A tumor in the hip: This can cause sensations similar to irritable hip.
- Juvenile idiopathic arthritis: This involves chronic joint inflammation with an unknown cause that occurs in children under 16 years of age. It can affect the hip joint.
Each can cause a very sick child to develop elevated C-reactive protein levels and sedimentation rates.
Sedimentation is the process through which red blood cells separate from blood serum, and it is part of the inflammation mechanism. The body sends out C-reactive protein in response to inflammation, which is why increased rates occur with irritable hip symptoms.
The child should rest and not attend school or nursery groups. They should avoid any participation in sports until the pain completely disappears.
It may be most comfortable to lie on their back, with their knee bent and turned out, and the foot on the affected side turned out.
With rest, symptoms often start to resolve within 3 days, and they should be gone within 2 weeks, though they may last 4–5 weeks.
A child with irritable hip usually does not need to spend time in the hospital.
The doctor may recommend nonsteroidal anti-inflammatory drugs or acetaminophen for pain relief. Children under 16 years of age should not take aspirin.
If the condition does not resolve, or if the pain persists or gets worse, seek medical attention. Ongoing or increasing pain may indicate a different underlying condition.