SAN FRANCISCO Few patients will admit that they compulsively pull out their hair, but a hair biopsy can help make the diagnosis of trichotillomania, Dr. Pearl C. Kwong said at a meeting sponsored by Skin Disease Education Foundation.
Clinically, the missing hair may be barely noticeable or may show signs of regrowth, such as uneven hair lengths. In contrast, hairs lost from alopecia areata will be approximately the same length if they regrow. If a patient picks hair from a favored area of the scalp, a "Friar Tuck" sign can be a clue to trichotillomania, she said. Patients usually have no skin abnormalities elsewhere.
Both children and adults with this impulse control disorder typically deny hair-pulling, and parents may be unwilling to accept a possible diagnosis of trichotillomania, said Dr. Kwong, a dermatologist in Jacksonville, Fla.
She recalled one girl who tried to hide her hair-pulling habit by eating the pulled hairs, which caused a bowel obstruction that required surgery. "To the end, the patient was denying that she ate her hair. The evidence was there in the bowel," Dr. Kwong said.
A hair biopsy can help with diagnosis. On histology, a high frequency of telogen hairs and a high frequency of noninflamed catagen hairs are typical of trichotillomania.
Accurate data on the prevalence of trichotillomania are hard to get because people hide the disorder, but it is estimated to affect 8 million people in the United States. The mean age of onset seems to be 8 years in boys and 12 years in girls, and 1%2% of college students have experienced or currently have symptoms. Adults with trichotillomania often report that the disorder started at a young age, even as young as 1 year old, and it is more likely to be diagnosed in women than in men.
In infants or young children, pulling or twisting the hair usually is self-limited and is a benign form of trichotillomania. It may be a sign of psychosocial stress or an underlying psychological problem, however, and can become a chronic condition.
Adolescents and adults diagnosed with trichotillomania tend to have a poorer prognosis, with chronic remissions and exacerbations. Patients may avoid social situations or have GI complaints. "There's usually underlying psychopathology in that family," Dr. Kwong said.
Although scalp hair is the most common target, hair-pulling may focus on any hairy parts of the body, including eyelashes, eyebrows, or hair in pubic, perirectal, or armpit areas. "I see a lot of kids who pull their eyelashes. Eyebrows, not as much," she said.
In young children, treat trichotillomania as a short-term habit disorder by cutting the hair very short (like a crew cut in boys) and applying Vaseline to the hair. "They stop their habit right away because it's so slippery they can't pull," Dr. Kwong said.
Referral to psychiatry, psychology, or developmental and behavioral pediatrics should be considered, especially in patients older than young children. Trichotillomania has been associated with obsessive control disorder, personality disorders, body dysmorphic disorder, schizophrenia, and mental retardation.
Occasionally, people with trichotillomania compulsively pull hair from other people or pets, she added.
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