Drugs that suppress the immune system are the foundation of treatment for CSS. A variety of immunosuppressive drugs are used to treat CSS. The severity of CSS is the most important factor in determining what drug to use. Disease severity can range from a more mild presence -- such as affecting the skin or joint -- to potentially life threatening.

Corticosteroids, such as prednisone or prednisolone, are the most common treatments. People who have a mild disease presence – those whose disease does NOT affect the nervous system, heart, kidneys, intestinal tract or show other features of severe disease -- might do extremely well on corticosteroid therapy alone. Once dramatic improvement is achieved, the drug dosage is reduced to the lowest amount that keeps the disease under control.

People with CSS who have critical organ system involvement are generally treated with corticosteroids combined with another immunosuppressive drug, such as cyclophosphamide, methotrexate, or azathioprine. These drugs are also used to treat other medical conditions. Azathioprine is used to prevent organ transplant rejection and is a treatment option for rheumatoid arthritis and lupus. High doses of cyclophosphamide and methotrexate are used to treat certain types of cancer. In cancer treatment, these drugs work by killing or slowing the growth of rapidly multiplying cancer cells. In vasculitis, these drugs are given at doses 10 to 100 times lower than that used to treat cancer. In vasculitis, these drugs’ primary effects are to suppress the immune system.

All immunosuppressive drugs can have side effects; and each drug can have side effects unique to it. To prevent or minimize side effects, watching for them is critical. A person with CSS may tolerate treatment when they first starting taking drugs; however, this does not guarantee that the same degree of tolerance will last over time. This makes ongoing monitoring essential, and in some instances, monitoring for long-term effects may be important even after the drug is stopped. Monitoring of blood tests is also used to evaluate the illness itself.