What causes hair loss?

There are many causes for hair lose : Hormones changes , illness , low iron in the blood ,Some medicines can cause hair loss,Fungal infections of the scalp

There can be various causes for hair loss:
# About 3 or 4 months after an illness or a major surgery, you may suddenly lose a large amount of hair. This hair loss is related to the stress of the illness and is temporary.
# Hormonal imbalance may also cause hair fall.
# If your thyroid gland is overactive or underactive, your hair may fall out. This hair loss usually can be helped by treatment thyroid disease.
# Many women notice hair loss 3 months after they deliver the baby and this is related to change in hormones only.
# It may also occur as a part of an underlying disease such as diabetes or lupus.