Aplastic anaemia is a condition in which production of red cells in the bone marrow is reduced. It involves failure to produce adequate red cells, white cells, and platelets.
This can be classified as:
1) Idiopathic aplastic anaemia: This constitutes 50 per cent of the cases. Its cause is unknown.
2) Acquired (secondary) aplastic anaemia: This is due to drug toxicity or sensitisation, e.g. chloramphenicol, sulphonamides, Phenylbutazone, and antimitotic drugs.
3) Aplastic anaemia associated with multiple congenital defects: This is hereditary and accompanied by skeletal, eye, heart, kidney, genital and other pigment abnormalities.