The diagnosis will be based on a combination of the clinical picture and results of some, but not necessarily all, of these tests. Left untreated, the condition leads to increasing weakness of muscle, inflammation of skin and the gut and worsening misery. Fortunately, treatment with steroids in relatively low dosage usually results in dramatic improvement, beginning in days with improvement in mood, followed by a gradual return of muscle strength. Once the response to treatment has been established the aim is slowly to decrease the steroids, but treatment may need to be quite prolonged - often for two years or more. Relapses may occur as treatment is being reduced or in association with chance infections.
Many children make a full recovery on steroid treatment alone.
When relapses do occur it is often possible to bring the symptoms under control again by increasing or reintroducing the steroids. However, some children prove more resistant to, or are unable to tolerate, steroids and then the use of other drugs which suppress the body's immune system is considered. These include azathioprine, cyclophosphamide and cyclosporin and intravenous infusions of immunoglobulins. Very rarely, children can become acutely and seriously ill and then plasma exchange has been shown to produce a temporary improvement while the other drugs are beginning to work. Drugs such as azathioprine are much slower in their speed of action than steroids and may take many weeks to produce the desired response.