Wegener's granulomatosis (WG) is a rare form of vasculitis, a disease characterised by inflammation of the walls of the blood vessels. This can result in damage to vital organs by restricting blood flow. WG is an autoimmune disease, meaning the body's immune system attacks its own tissues.

Churg–Strauss syndrome is similar to WG, but affects mainly the lungs and produces lesions under the skin.

Sarcoidosis is a multi-system disorder characterised in affected organs by a type of inflammation called granulomas. The cause is unknown. It especially affects the lymph nodes around the lungs, skin, eyes, liver and spleen.

There are other medical conditions that are similar to WG and in some cases have symptoms that run parallel to those of WG. They include:

• Sjogrens syndrome – A syndrome of unknown cause that tends to occur within certain autoimmune disorders such as arthritis or lupus, but mostly affecting the tear glands and saliva.
• Lupus erythematosis – A chronic disease causing inflammation of the connective tissues and affecting many systems including the skin, kidneys, heart and joints.
• Crohn’s disease – A chronic inflammatory condition of the digestive and intestinal tract.