Churg-Strauss syndrome, also known as Eosinophilic Granulomatosis, is one of many forms of vasculitis, which are characterized by inflammation of blood vessels. This inflammation can restrict blood flow to vital organs and tissues, sometimes permanently damaging them. CSS occurs in patients with a history of asthma or allergy and features inflammation of blood vessels in the lungs, skin, nerves and abdomen.


CSS is a highly variable illness and some people have only mild symptoms, whereas others experience severe or life-threatening complications. CSS causes fever, fatigue, weight loss and sinus or nasal passage inflammation in the patient with asthma. Sometimes the asthma actually improves somewhat as the disease intensifies elsewhere. Cough, shortness of breath and chest pain can occur as the lungs are affected and skin lumps can appear on the extremities. Diarrhea and pain in the belly occur due to blood vessel inflammation within the abdomen. The bladder and prostate gland can become inflamed.

There are three stages of CSS, each with its own signs and symptoms, but not everyone develops all three phases or in the same order. The stages may include:

 Allergic stage, that may cause:

  • Asthma;
  • Hay fever;
  • Sinus pain and inflammation.

Hypereosinophilia stage may include: 

  • Fever;
  • Loss of appetite;
  • Weight loss;
  • Asthma;
  • Fatigue;
  • Cough;
  • Abdominal pain;
  • Gastrointestinal bleeding.

Vasculitic stage may include:

  • Rash or skin sores;
  • Joint aches and swelling;
  • Severe pain, numbness and tingling in the hands and feet;
  • Severe abdominal pain;
  • Diarrhea, nausea and vomiting;
  • Shortness of breath from asthma or congestive heart failure;
  • Hemoptysis;
  • Chest pain;
  • Irregular heartbeat;
  • Hematuria.


Since exact CSS is a rare disease, its cause is still not known, but it involves an abnormal over-activation of the immune system in a person with underlying asthma. Nonetheless, whether they actually cause the disease or whether the patients that take them have more severe asthma that lends a tendency toward the development of CSS is not clear yet.

It is also likely that an overactive immune system response is triggered by a combination of genes and an environmental trigger. Instead of simply protecting against invading organisms such as bacteria and viruses, the immune system overreacts and targets healthy tissue, causing widespread inflammation.

Some people have developed CSS after using an asthma and allergy medication called montelukast or after switching from low-dose oral systemic steroids to inhaled steroid medications. However, no clear connection between CSS and any medication has been proved.



CSS can affect many organs, including the lungs, skin, gastrointestinal system, kidneys, muscles, joints and the heart. Without treatment, the disease may be fatal. Complications depend on the organs involved and may include:

  • Peripheral nerve damage;
  • Skin scarring;
  • Heart disease; or
  • Kidney damage.


Risk Factors

Possible risk factors for CSS include age (more precisely, people who are elder than 45 years) and history of asthma or nasal problems.