Many conditions and diseases, and improper hair care can result in excessive hair loss. While losing 50 to 100 hairs a day is normal, people who notice their hair shedding in large amounts after combing or brushing, or whose hair becomes thinner or falls out, should consult a dermatologist for proper diagnosis and treatment.

The most common cause of excessive hair loss is hereditary thinning or baldness.

Other causes of hair loss, some of which are temporary, include:

Some cancer treatments, such as radiation therapy and chemotherapeutic medications;
Alopecia areata, a type of hair loss that affects all ages, which causes hair to fall out in patches;
Excessive or improper use of styling products, such as perms, dyes, gels, relaxers and sprays can cause weathering – or hair breakage;
Hairstyles that pull on the hair, like ponytails and braids;
Shampooing, combing, or brushing hair too much (100 strokes or more a day) or too hard, or pulling it out;
One of at least 30 diseases, such as thyroid disease;
Following childbirth, major surgery, a high fever or severe infection, or even the flu;
Inadequate protein in the diet or eating disorders, such as anorexia and bulimia;
Certain prescription drugs (including blood thinners, high-dose vitamin A and medicines for arthritis, depression, gout, heart problems and high blood pressure);
Use of birth control pills (usually in women with an inherited tendency toward hair thinning) or a few months after discontinuation of oral contraceptives;
Hormonal imbalances, especially in women; and
Ringworm of the scalp, a contagious fungal infection most common in children.

Treatment of Hair Loss

Topical and oral medications have been shown to help in the regrowth of hair or slow down hair loss.
Hair loss caused by diseases such as thyroid disease can be reversed with treatment of the underlying disease.
Topical or oral estrogen, or other hormones, are sometimes recommended for women experiencing hair loss.
Hair transplantation is a permanent form of hair replacement using surgery that involves moving some existing scalp hair to bald or thinning parts.