Irritable hip occurs when the synovial membrane in the hip area becomes irritated and inflamed.
All of the body's joints have a thin layer of delicate tissue that lubricates the joint and helps it to move. The layer of tissue is called the synovial membrane.
Exactly what causes the membrane to become irritated and inflamed is unclear.
Some cases of irritable hip occur after a child has had a viral infection of their chest, throat or digestive system. As a result of this, many experts think that 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.
