Multiple myeloma (MM) is a malignant tumor of plasma cell characterized by overproduction of abnormal plasma cells in the bone marrow and skeletal destruction. The clinical features are bone pain, renal impairment, immunodeficiency, anemia and presence of abnormal immunoglobulins (Ig).

Rapid swelling (edema) of the dermis, subcutaneous tissue, mucosa and submucosal tissues of the skin of the face, normally around the mouth, and the mucosa of the mouth and/or throat, as well as the tongue during a period of minutes to several hours. The swelling can also occur elsewhere, typically in the hands. Angioedema is similar to urticaria, but the swelling is subcutaneous rather than on the epidermis.