Cold hemagglutinin disease is a rare autoimmune hemolytic anemia, characterized by the production of antibodies that attack the patient's own red blood cells at low temperatures. Some of the synonyms for this condition include: cold autoimmune hemolytic anemia, cold agglutinin syndrome, and cold antibody hemolytic anemia. The disease typically affects adults over the age of 50 and can be associated with underlying conditions such as lymphoma, viral infections, or autoimmune disorders. Symptoms include fatigue, shortness of breath, jaundice, and painful cyanosis of the extremities. Treatment options depend on the severity of the disease and may involve blood transfusions, immunosuppressive therapy, or rituximab.