Connective tissue diseases are disorders that involve protein-rich tissues. Examples include fat, bone, and cartilage. These disorders often involve joints, muscles, and skin. There are more than 200 different disorders that can affect connective tissue. The specific causes and symptoms vary depending on the disorder.

Autoimmune diseases are known to be the third most dangerous in the world, after cardiovascular diseases and cancer. Autoimmune diseases are difficult to cure completely. Recent studies have shown that air pollution can increase the incidence of autoimmune diseases. However, if the disease is detected and treated early, it can be overcome and prevent possible bad complications.