Although it is unknown what causes most types of vasculitis, immune system abnormality, inflammation of blood vessels, and genetic factors appear to be somewhat important in the cause of the disease. Vasculitis can also be caused by an immune or allergic reaction in the vessel walls.
Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance. When an allergen enters the body, it causes the body's immune system to develop an allergic reaction in a person with an allergy to it. This reaction can occur when the immune system attacks a normally harmless substance (the allergen). The immune system calls upon a protective antibody called immunoglobulin E or IgE to fight these invading substances.
An individual's genetic make-up helps determine what they are allergic to and the severity of their allergies. Allergic reactions can be mild or deadly. Mild reactions include itching, rash, and hives. More serious reactions involve swelling of lips, tongue, and difficulty breathing that can lead to death.Allergic reactions are different from common side effects of many drugs such as a headache or stomach upset.ny drug or a component in a drug can case an allergic reaction. Penicillin and related drugs, sulfa drugs, insulin, and iodine commonly cause allergic reactions. Sometimes it is a component or substances used for packaging or administering the drug that causes the allergy.