Irritable hip is a common childhood condition that causes symptoms such as hip pain and limping.
Doctors sometimes refer to irritable hip as transient or toxic synovitis.
Hip pain isn't usually severe, but your child may be reluctant to place weight on the affected leg.
Occasionally, an irritable hip may also cause:
pain in the knee or thigh
restricted movement in one of the hip joints
a slightly higher temperature than normal – a normal temperature is around 37C (98.6F)
In younger children who are unable to speak, the only noticeable symptom may be crying at night.
When to see your GP
Although irritable hip is usually a mild condition, you should take your child to see your GP if you are concerned about their hips, so that a diagnosis can be confirmed.
This is because irritable hip shares symptoms of more serious hip conditions, such as septic arthritis (an infection inside the hip) or Perthes disease.
Your GP will examine their hip and may recommend further tests to rule out other causes. These tests include:
an X-ray to see if there's a problem with your child's bones
blood tests to look for a bone or joint infection
an ultrasound scan that will highlight any fluid that may be on the joint
If there's fluid on the joint, a sample can be removed and checked for an infection. Just removing the fluid from the joint can ease the symptoms.
What causes irritable hip?
The condition develops when the lining that covers the hip joint (the synovial membrane) becomes irritated and inflamed, although the cause of inflammation is unclear.
Some cases of irritable hip occur following a viral infection in the chest, throat or digestive system. Many experts think the synovial membrane in the hip becomes inflamed as a complication of the infection. However, there is no hard evidence to support this theory.
Another theory is that a hip injury may cause the swelling, although many cases develop in children who do not have a history of injury.
Who is affected?
Irritable hip can affect boys and girls of any age, but is most common between the age of four and 10 years old. The condition affects twice as many boys than girls.
Is it serious?
As a parent, it can be very worrying if your child is diagnosed with irritable hip and is struggling to walk. However, the condition is usually short-lived.
Most cases don't require specific treatment, because the pain usually passes within two weeks.
Ibuprofen, which is available over the counter, can be used to relieve pain and reduce inflammation. Your child should also rest the affected leg until symptoms have passed.
A small number of children with irritable hip go on to have further episodes. However, these episodes usually become less frequent and eventually stop when the child is older.
Treating irritable hip
Most children with irritable hip can be treated at home using a combination of painkillers and bed rest.
The non-steroidal anti-inflammatory drug (NSAID) ibuprofen is the painkiller usually recommended to treat hip pain. Ibuprofen should help relieve pain, as well as reduce inflammation and speed up your child's recovery.
Do not give aspirin to children under the age of 16, because it can trigger a rare condition called Reye's syndrome.
Massaging the affected hip and applying heat may also help to reduce your child's hip pain.
Bed rest is recommended until the symptoms of pain resolve, which usually takes between seven and 10 days.
Traction may sometimes be applied in hospital during bed rest. This is where bandages and weights are used to reduce the pain by resting the hip joint.
Your child may be admitted to hospital if the diagnosis is uncertain or painkillers and bed rest haven't eased the pain.
Further tests may be given to rule out an infection inside the hip joint (septic arthritis).
Septic arthritis can be treated by taking antibiotics and draining the infected fluid out of the joint.
It usually takes a couple of weeks to recover from irritable hip, although your GP may recommend that your child does not play sport or take part in any strenuous activities for at least another two weeks following treatment. This is to reduce the chances of irritable hip returning.
Swimming is a good way to strengthen the joint and get it moving again.
A follow-up appointment may be needed up to six months later. This is to rule out other hip conditions that can also cause pain, stiffness and a limp.