Churg-Strauss syndrome Dr Rob Hicks This rare condition can affect the blood vessels, the lungs, nerves and many other parts of the body.

In this article

What is it? What causes it?

Who's affected? What are the symptoms?

How is it diagnosed? What's the treatment?

CSS is an autoimmune condition, which means the body turns on itself.

White blood cells called eosinophils become too numerous and attack the body's healthy tissues. During this process, the eosinophils cluster together and release harmful granules that collect in various parts of the body as inflammatory nodular lesions. This is called granulomatosis.

Damage to the blood vessels results in them becoming characteristically inflamed, a condition known as vasculitis.

The lungs become damaged in about 70 per cent of CSS cases. Outside the circulation and lungs, the most common place for problems to develop is in the skin. Nodules or a purpuric rash - where blood has haemorrhaged into the skin - appear. The skin is affected in around two-thirds of those with CSS.

The digestive and nervous systems may also be damaged. If the eosinophils block or damage the small blood capillaries that feed the nerves of the hands and feet, the nerves may die. This results in pain and possible paralysis.

It's not known precisely what causes these white blood cells to behave in this way. Experts believe it's an allergic reaction as the diagnosis of CSS is often preceded by a history of allergies or asthma.

Other common names for CSS are allergic granulomatosis and allergic angiitis.

It affects slightly more men than woman and can start at any age.

The first symptoms of CSS are those of a flu-like illness. Generalised aches and pains, fever, cough and a loss of appetite may be accompanied or followed by continued malaise and weight loss.

Subsequent symptoms depend on the phase of the illness and the organs involved. For example, pain may be felt in a particular area of the body or organ. Numbness and tingling of the hands and feet may occur and worsen so that much feeling and function is lost. This is known as peripheral neuropathy.

Sometimes people with CSS experience visual problems and severe abdominal pain.

Making the diagnosis of CSS isn't easy. Not only are the initial symptoms vague and common to many other conditions, but even when the fuller picture appears a number of similar illnesses need to be considered and ruled out first.

To reach a diagnosis needs a bit of lateral thinking, some blood tests, x-rays and often a biopsy of the muscles.

There's no single test for CSS, so to make a diagnosis someone has to have at least four of the following six criteria:

• Asthma
• Abnormally high levels of eosinophils in the blood
• Neuropathy
• Pulmonary (lung) infiltrates
• Paranasal sinus abnormality
• Eosinophils outside the circulation on biopsy

Treatment involves using different drugs to achieve three goals:

• Suppression of inflammation
• Suppression of the immune system
• Removal of immune complexes that move around the body causing harm to healthy tissue

This can bring the condition under control and relieve symptoms, and for many people is very effective.

This article was last medically reviewed by Dr Rob Hicks in January 2008