Autoimmune haemolytic anaemia, cold type

Cold autoimmune haemolytic anaemia comprises two types of autoimmune haemolytic anaemia (AIHA) defined by the presence of cold autoantibodies (autoantibodies which are active at temperatures below 30°C): cold agglutinin disease (CAD), which is the more common, and paroxysmal cold haemoglobinuria (PCH). CAD is more common in people over the age of 55 years, while PCH typically presents in young children. CAD is caused by IgM autoantibodies while PCH is caused by an IgG immunoglobulin.