Inflammatory diseases are a group of disorders that involve the body's immune system. These diseases can affect any part of the body, including the skin, joints, lungs, heart, and blood vessels. Common inflammatory diseases include rheumatoid arthritis, lupus, inflammatory bowel disease, and psoriasis. Symptoms of inflammatory diseases vary depending on the type of disease, but can include joint pain, swelling, fatigue, fever, and skin rashes. Treatment for inflammatory diseases typically involves medications to reduce inflammation and suppress the immune system.