There are many possible causes of temporary hair loss, which include:
childbirth; when a woman is pregnant she loses less hair than usual, but two to three months after giving birth, some women notice losing large amounts of hair
high fever, severe infection or the ’flu
thyroid disease
insufficient protein in your diet or extreme dieting
some medications, including the oral contraceptive pill
cancer treatment
iron deficiency
psychological causes; such as obsessive compulsive disorder and severe stress
major surgery or chronic illness
fungal infection of the scalp
damage from rollers or tight braiding and plaiting
damage from hair straighteners or irons
chemical damage from commercial hair relaxing products
alopecia areata: a patch of hair falls out, resulting in totally smooth, round patches on your scalp, about the size of a coin or larger