Rosai-Dorfman disease (RDD) is usually found in children but can also affect adults. RDD can happen in people who have autoimmune diseases or other blood cancers. RDD usually causes swollen lymph nodes, but it can affect any part of the body. After the lymph nodes, the most frequently affected areas of the body are the bones and skin. The brain and other areas can also be affected. Some forms of RDD do not require treatment and can improve on their own. For those that do not, treatments include surgery, steroid medications, and in some cases, chemotherapy or targeted drugs.