The vast majority of children suffering with hair loss do so because of the following conditions. All of these conditions should be easily diagnosed by your pediatrician or by a pediatric dermatologist.

1. Tinea capitis (ringworm of the scalp) is a disease caused by a superficial fungal infection of the skin of the scalp, eyebrows, and eyelashes, with a propensity for attacking hair shafts and follicles. The disease is considered to be a form of superficial mycosis or dermatophytosis. Several other names are used when referring to this infection, including ringworm of the scalp and tinea tonsurans. In the US and other regions of the world, the incidence of tinea capitis is increasing.

The tinea capitis infection is the most common cause of hair loss in children.

Children with tinea capitis usually have patchy hair loss with some broken-off hairs visible just above the surface of the scalp. The patches of hair loss are usually round or oval, but sometimes irregular. Sometimes the hairs are broken right at the surface, and look like little black dots on the scalp.

Sometimes gray flakes or scales are seen.

Diagnosis: The diagnosis is suspected primarily based on the appearance of the scalp. A Wood's lamp test may be performed to confirm the presence of a fungal scalp infection. Wood's lamp is a test that is performed in a dark room where ultraviolet light is shined on the area of interest. No scalp biopsy is necessary for the diagnosis.

Treatment: Tinea capitis is usually treated with an antifungal, such as griseofulvin, which is taken by mouth for 8 weeks.

Tinea capitis is also treated with Nizoral shampoo, which is used to wash the scalp 2-3 times a week. It is very important to continue the use of the oral medication and shampoo for the entire 8 weeks. Treatment failure is common when medications are not taken everyday for the full 8 weeks.

Children who have tinea capitis are not required to leave school if treatment is used as directed. Most children are not contagious when using the oral medication and shampoo.

2. Alopecia Areata is the sudden appearance of round or oval patches of hair loss. These patches are completely slick bald or smooth without any signs of inflammation, scaling, or broken hairs. They appear literally overnight, or sometimes over a few days.

Alopecia areata is thought to be caused by the body's immune system attacking the hair follicles. At any given moment about 1 per 1,000 children has alopecia areata. About 25% of these children will also have pitting or ridging of the nails.

With appropriate treatment, a large percentage of patients will have all of their hair back within one year -- many will have it sooner. Children with alopecia areata should be under the care of a dermatologist. About 5% of children with alopecia areata will go on to develop alopecia totalis -- the loss of all the hair on the scalp. Some of these will develop alopecia universalis -- the complete loss of body hair.

Diagnosis: Currently there are no conclusive diagnostic tests for alopecia areata. Dermatologists deduce alopecia areata by a process of elimination of other hair loss causes and the close examination of the bald patch itself. Typically, the initial alopecia areata lesion appears as a smooth bald patch sometimes within 24 hours. Some people feel a tingling sensation or pain in the affected area. The scalp is the most commonly affected area, but alopecia areata can present in any region of hair on the body. Hair pull tests are sometimes conducted at the margins of lesions. If hair is easily pulled out, it is indicative that the lesion is active and further hair loss should be anticipated. Since alopecia areata is fairly distinctive it is usually correctly diagnosed with a simple visual examination.

Treatment: There is no cure for alopecia areata and unfortunately since there is little understanding of the disease there are no FDA approved drugs or treatments specifically designed to treat AA. There are, however, several drugs being prescribed off label for the treatment of AA. These drugs are incorporated into the treatment protocols that appear to help a certain percentage of those afflicted with this disease.

Keep in mind that while these treatments may promote hair growth, none of them prevent new patches or actually cure the underlying disease. Consult your health care professional about the best option for your child.

Alopecia areata is an unpredictable disease and even with complete remission it is possible for it to occur again throughout your child's lifetime.

3. Trauma to the hair shaft is another common cause of hair loss in children. Often the trauma is caused by traction (consistently worn tight braids, pony-tails, etc.) or by friction rubbing against a bed or wheelchair for example). It can also be caused by chemicals burns

Another misunderstood cause of trauma hair loss is called trichotillomania the habit of twirling or plucking the hair. Trichotillomania is thought to be an obsessive-compulsive disorder that can be extremely difficult to treat since the patient usually feels compelled to pluck their hair. The hair loss is patchy, and characterized by broken hairs of varying length. Within the patches, hair loss is not complete. (Some children with trichotillomania also have trichophagy -- the habit of eating the hair they pluck. They develop abdominal masses consisting of balls of undigested hair.) As long as the hair trauma was not severe or chronic enough to cause scarring, the hair will re-grow when the trauma is stopped

4. Telogen effluvium, Another common cause of hair loss in children. To understand telogen effluvium, one must understand a hair's normal life cycle. An individual hair follicle has a long growth phase, producing steadily growing hair for 2 to 6 years (on average 3 years). This is followed by a brief transitional phase (about 3 weeks) when the hair follicle degenerates. This in turn is followed by a resting phase (about 3 months) when the hair follicle lies dormant. This last phase is called the telogen phase. Following the telogen phase, the growth phase begins again -- new hairs grow and push out the old hair shafts. The whole cycle repeats. For most people, 80% to 90% of the follicles are in the growth phase, 5% are in the brief transition phase, and 10% to 15% are in the telogen phase. Each day about 50-150 hairs are shed and replaced by new hairs. In telogen effluvium, something happens to interrupt this normal life cycle and to throw many or all of the hairs into the telogen phase. Between 6 and 16 weeks later, partial or complete baldness appears. Many different events can cause telogen effluvium, including, extremely high fevers, surgery under general anesthesia, excess vitamin A, severe prolonged emotional stress such as a death of a loved one, severe injuries and the use of certain prescription medication such as accutane for acne.

Diagnosis: There are no conclusive diagnostic tests to accurately diagnose Telogen effluvium. A detailed medical history is taken, but it usually comes down to the experience of the physician to make the diagnosis.

Treament : In children once the stressful event is over full hair growth usually occurs between six months and I year.

Source: American Hair Loss Association