Browse comprehensive, doctor-reviewed information on 5 health conditions.
Allergies occur when the immune system reacts to a foreign substance that is typically harmless. Common allergens includ...
HIV (human immunodeficiency virus) is a virus that attacks the immune system. If not treated, it can lead to AIDS (acqui...
Systemic lupus erythematosus (lupus) is a chronic autoimmune disease that can damage any part of the body, including ski...
Lyme disease is an infectious disease caused by the bacterium Borrelia burgdorferi, transmitted through the bite of infe...
Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the joints. It causes the immune system...