Acquired hemolytic anemia

Acquired hemolytic anemia can be divided into immune and non-immune mediated forms of hemolytic anemia.

Immune
Immune mediated hemolytic anemia (direct Coombs test is positive)
 * Autoimmune hemolytic anemia
 * Warm antibody autoimmune hemolytic anemia
 * Idiopathic
 * Systemic lupus erythematosus (SLE)
 * Evans' syndrome (antiplatelet antibodies and hemolytic antibodies)
 * Cold antibody autoimmune hemolytic anemia
 * Idiopathic cold hemagglutinin syndrome
 * Infectious mononucleosis and mycoplasma ( atypical) pneumonia
 * Paroxysmal cold hemoglobinuria (rare)
 * Alloimmune hemolytic anemia
 * Haemolytic disease of the newborn (HDN)
 * Rh disease (Rh D)
 * ABO hemolytic disease of the newborn
 * Anti-Kell hemolytic disease of the newborn
 * Rhesus c hemolytic disease of the newborn
 * Rhesus E hemolytic disease of the newborn
 * Other blood group incompatibility (RhC, Rhe, Kidd, Duffy, MN, P and others)
 * Alloimmune hemolytic blood transfusion reactions (ie from a non-compatible blood type)
 * Drug induced immune mediated hemolytic anemia
 * Penicillin (high dose)
 * Methyldopa

Non-immune
Non-immune mediated hemolytic anemia (direct Coombs test is negative)
 * Drugs (i.e., some drugs and other ingested substances lead to haemolysis by direct action on RBCs, e.g. ribavirin )
 * Toxins (e.g., snake venom; plant poisons such as aesculin)
 * Trauma
 * Mechanical (heart valves, extensive vascular surgery, microvascular disease)
 * Microangiopathic hemolytic anemia (a specific subtype with causes such as TTP, HUS, DIC and HELLP syndrome)
 * Infections (Note: Direct Coombs test is sometimes positive in hemolytic anemia due to infection)
 * Malaria
 * Babesiosis
 * Septicaemia
 * Membrane disorders
 * Paroxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface proteins)
 * Liver disease

Drug induced hemolysis
Drug induced hemolysis has large clinical relevance. It occurs when drugs actively provoke red blood cell destruction. It can be divided in the following manner:


 * Drug-induced autoimmune hemolytic anaemia


 * Drug-induced nonautoimmune hemolytic anaemia

A total of four mechanisms are usually described, but there is some evidence that these mechanisms may overlap.