Allergic stage
This is usually the first stage of Churg-Strauss syndrome. It's marked by a number of allergic reactions, including:

   * Asthma. The primary sign of Churg-Strauss syndrome, asthma develops on average three to nine years before other signs and symptoms appear. In people with Churg-Strauss syndrome who already have asthma, symptoms usually become worse and may require steroids for control. Other people develop what is known as late-onset asthma. Developing asthma, even later in life, doesn't necessarily mean that you have Churg-Strauss syndrome, however. Churg-Strauss occurs only very rarely as a complication of asthma.
   * Hay fever (allergic rhinitis). This affects the mucous membranes of your nose, causing runny nose, sneezing and itching.
   * Sinus pain and inflammation (sinusitis). You may experience facial pain and develop nasal polyps, which are soft, noncancerous (benign) growths that develop as a result of chronic inflammation.

Eosinophilic stage
An eosinophil is a type of white blood cell that helps your immune system fight certain infections. Normally, eosinophils make up only a small percentage of white blood cells, but in Churg-Strauss syndrome, abnormally high numbers of these cells (hypereosinophilia) are found in your blood or tissues, where they can cause serious damage.

Signs and symptoms of hypereosinophilia depend on which part of your body is affected. Your lungs and digestive tract — including your stomach and esophagus — are involved most often.

Hypereosinophilia can indicate a number of allergic conditions and doesn't necessarily mean you will develop Churg-Strauss syndrome.

Broadly speaking, signs and symptoms of the hypereosinophilia phase may include:

   * Fever
   * Weight loss
   * Asthma
   * Fatigue
   * Night sweats
   * Cough
   * Abdominal pain
   * Gastrointestinal bleeding

This phase can last months or years, and your symptoms may disappear at times, only to return later. You may also experience symptoms of hypereosinophilia and systemic vasculitis — the third stage of Churg-Strauss syndrome — at the same time.

Vasculitic stage
The hallmark of this stage of Churg-Strauss syndrome is severe blood vessel inflammation (vasculitis). By narrowing blood vessels, inflammation reduces blood flow to vital organs and tissues throughout your body, including your skin, heart, peripheral nervous system, muscles, bones and digestive tract. Occasionally, your kidneys may also be affected.

During this phase, you may feel generally unwell and have unintended weight loss, swollen lymph nodes, weakness and fatigue.

Depending on which organs are affected, you may also experience:

   * Rash or skin sores
   * Joint aches and swelling
   * Severe pain, numbness and tingling in your hands and feet (peripheral neuropathy)
   * Severe abdominal pain
   * Diarrhea, nausea and vomiting
   * Shortness of breath (dyspnea) from asthma or congestive heart failure
   * Coughing up blood (hemoptysis)
   * Chest pain
   * Irregular heartbeat
   * Blood in your urine (hematuria)