A condition is which hair in the anagen (growth) phase of the hair cycle is shed, often by breaking off at the level of the scalp. A frequent cause is exposure to a toxic agent (such as chemotherapy drugs, colchicine, mercury, thallium), ionizing radiation (cancer therapy or accidental exposure), and severe protein restriction in a protein-deficient diet. Some toxic agents-notably thallium-can be fatal with a single dose because they cannot be removed from tissue before they cause death. Anagen effluvium usually resolves after removal of the toxic agent or addition of sufficient protein to the diet. The classic condition due to protein-calorie malnutrition is kwashiorkor, recognized especially in children with protruding abdomens and tangled, broken hair.
Hair Loss and Its Causes