Dermatologists use the terms “hair loss and alopecia” interchangeably. Hair loss may be divided into two major categories: thinning and shedding. When hair “thins,” the hair become smaller and smaller in diameter, it miniaturizes, i.e. its diameter reduces from 60 microns to less than that. Patients with early thinning, retain the same number of hairs per square inch as they did originally. However, as each hair gets progressively smaller, a bald spot becomes more and more visible. Eventually the hair becomes so miniaturized that it disappears, the hair is then considered lost, and a hairless bald spot results. Thinning is a slow process, and it’s unusual to see an increased number of hairs in your sink or your hairbrush. Thinning is what takes place in male pattern hair loss.

When hair “sheds”, the scalp skin becomes visible because non-miniaturized hairs have fallen out. Patients with hair shedding will often see hair in their brush, on their pillow case, and on the floor. The medical factors responsible for hair shedding are quite different than those which cause hair thinning. Shedding can occur in either anagen or telogen phase and may be the result of fever, childbirth, or chemotherapy, etc. Most times, a video microscopic examination is required to differentiate between anagen shedding and telogen shedding.


When alopecia or hair loss takes place, it may take three different configurations on the scalp - diffuse, patterned, and spotty.

Diffuse hair loss describes hair falling out equally over the entire scalp. This type of hair loss is usually of the “shedding” rather than “thinning” variety, and may be the result of fever, childbirth, chemotherapy, hyperthyroidism, etc.

Pattern hair loss is characterized by a loss of hair on the front and crown of the scalp, with no loss on the back and sides. This is seen in common male balding and in some women as well. Pattern hair loss is a form of “thinning” rather than “shedding.” CLICK TO ENLARGE It is slow and progressive. Rarely is the hair count of lost hairs greater than the average fifty per day. Hair loss usually begins in Zone 1 and progresses to 2, 3, 4 etc. Sometimes it begins in Zone 5. In both cases, it never involves Zone 10, the area from which hair transplant grafts are taken.

Spotty hair loss is a unique form of loss characterized by a moth-eaten appearance of the scalp and it is typically a “shedding type” of loss. Unlike diffuse and pattern losses. the spotty hair loss occurs with a random, irregular configuration.

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A common cause of a spotty loss is alopecia areata, an immunologic rejection of one’s own hair. This disorder is more common in children, will often correct with no treatment at all, but may on rare occasions, progress to be quite extensive. Typical alopecia areata usually responds quite well to local injections of cortisone into the hairless areas. The skin in the area of hair loss is normal in appearance.

White hair is more resistant to alopecia areata than is dark hair. If an individual with salt and pepper hair develops a case of severe alopecia areata, his hair might be described as “turning gray overnight.” Reason: the dark hairs have fallen rapidly over a few days, and only the gray hairs remain.

When the area of spotty hair loss is associated with scaling of the skin, the diagnosis is often ringworm or fungus infection. Fungus infections of the scalp must be treated with a course of anti-fungal pills. Other forms of spotty hair loss may be scarring, congenital defects, discoid lupus erythematosis, etc. Unlike alopecia areata, these are associated with changes in skin as well.

Hair loss, due to shedding, is one of the more predictable effects of hormonal changes in pregnancy. Approximately 3 to 4 months after delivery, more than 50% of mothers report a mild to moderate hair fall called telogen effluvium. This often continues for about six months, and then gradually slows and stops. The lost hair then begins to re-grow at the normal rate of one half inch per month. Unlike hair loss in men, it affects the entire scalp and is not limited to the top of the head. The hair loss of pregnancy does not progress to eventual baldness.

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Hair loss following delivery is due to the abnormal synchronization of growing and resting phases in the hair growth cycle. The average non-pregnant woman loses about 50 to 100 hairs a day. In pregnancy, hormones influence the hair to stop falling. A few months after childbirth, normal hair loss resumes, and the loss that would have taken place over nine months, is dramatically compressed into one or two months. The hair loss of pregnancy is a normal phenomenon. Doctors have observed that women, who stop birth control pills, have a similar hair loss.

It is not unusual for hair loss to follow a high fever -- usually about two to three months later. The loss is a telogen shedding that eventually self corrects. When a high fever persists, the synchronization between anagen and telogen hairs becomes disrupted, and many hairs enter the two to three month telogen phase. When anagen is re-established, the telogen hairs are pushed out by the newly-forming anagen hairs. The medical term for this phenomenon is “telogen effluvium.”

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When women lose hair in a pattern similar to men, it is cause for medical evaluation. If significant hormonal imbalance has taken place, the loss may be associated with irregular periods, inability to become pre growth of new body hair. Most women with pattern hair loss do not have a hormone imbalance. Many have a family history of similar loss in their female relatives, and but most are otherwise healthy individuals. Pattern hair loss in women should be medically evaluated with hair density counts, distribution analysis, and hormonal screening tests. The treatment may be hormone therapy, topical minoxidil, or hair transplant surgery.

Unlike male pattern balding, female pattern balding is not associated with recession of the frontal hair line