Dr. Greene’s Answer:
An average human scalp contains about 100,000 hairs. Even when most of these hairs remain healthy, it is little consolation to the child with hair loss. Sergio, I expect that your 8-year-old’s hair loss concerns him even more than it concerns you.
Hair loss in children is much more common than most people suspect. Catherine Wiley, M.D., of the Connecticut Children’s Medical Center, estimates that hair loss is responsible for 3% of all pediatric office visits. The list of all the possible causes for hair loss is exceedingly long. Thankfully, the great majority of children who lose their hair do so from one of four causes — all of which usually resolve with the appropriate treatment:
1. A fungal infection similar to athlete’s foot is the most common cause of hair loss in children. Tinea capitis is the technical name for this scalp infection (tinea pedis is the name if the infection is on the foot). Tinea capitis is rare after puberty. 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. Treatment usually requires an oral anti-fungal medication that can be prescribed by your doctor. The medication must be taken for approximately 2 months, but is very effective at curing the infection and restoring the hair. Sometimes use of a shampoo containing 2.5% selenium sulfide is also necessary to treat this infection and to reduce the contagiousness of children with tinea capitis.
2. Alopecia areata (which means “localized baldness”) is the sudden appearance of sharply circumscribed round or oval patches of hair loss. These patches are smooth — without inflammation, scaling, or broken hairs. They appear literally overnight, or sometimes over a few days. Sometimes the hairs around the border of the bald spots are very easily plucked, and look like exclamation points due to the swollen bulb at the base. Alopecia areata is thought to be caused by the body’s immune system attacking some of 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. Overall, the outlook for children with alopecia areata is quite good. With appropriate treatment, about 95% will have all of their hair back within one year — many will have it much sooner. Children with alopecia areata should be under the care of a dermatologist, a physician who specializes in the treatment of skin disorders. 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. A wide variety of treatments are available, mostly aimed at suppressing or distracting the immune system. The National Alopecia Areata Foundation is a valuable resource for those dealing with this condition.
3. Trauma to the hair shaft is another common cause of hair loss in children. Often the trauma is caused by traction (braids, pony-tails, curlers, etc.) or by friction (hats, hairbands, or rubbing against a bed or wheelchair). It can also be caused by chemicals or by burns. Another important cause of hair trauma is called trichotillomania — the habit of twirling or plucking the hair. Trichotillomania is very similar to thumb-sucking or nail-biting. Children with trichotillomania tend to damage their hairs while they are falling asleep or watching television. 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, the other common cause of hair loss in children, affects children and adults. It is responsible for more hair loss than any other cause except male-pattern baldness. 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 100 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
- high fevers
- certain medicines — including chemotherapy
- crash diets
- excess vitamin A
- emotional stress
- severe injuries
Once the stressful event is over, complete hair growth usually occurs within 6 months. In the meantime, it is wise to avoid overly vigorous shampooing, brushing, or drying.
Sergio, I urge you to have your son evaluated by a physician to pinpoint the cause of the hair loss, and to initiate appropriate treatment. In some cases, early treatment will make the difference in restoring the hair.