Background
Trichotillomania (hair-pulling disorder) is characterized by the persistent and excessive pulling of one’s own hair, resulting in noticeable hair loss. [1, 2, 3] Hair pulling can occur in any area of the body where hair grows. The scalp is the area most commonly affected, followed by the eyelashes and eyebrows. [4] The hair loss that results from hair pulling can range from small undetectable areas of hair thinning to complete alopecia.
Trichotillomania most commonly presents in early adolescence, with the peak prevalence between ages 4 and 17 years. [5] The disorder has both physical and psychosocial implications. Affected patients may experience distress, moderate impairment of social or academic functioning, and adverse impacts on family relationships. [4]
Although trichotillomania is more often a focus of behavioral and psychiatric publications than of dermatologic publications, patients are more likely to present to dermatologists than to mental health professionals. Accordingly, it is important for dermatologists to be familiar with the clinical features and treatment options for these patients.
Trichotillomania must be differentiated clinically from other alopecias (eg, alopecia areata, traction alopecia, androgenetic alopecia, pseudopelade, alopecia mucinosa) through careful history-taking and physical examination. Dermatologists, psychologists, and psychiatrists should be familiar with the key features of the disorder because earlier treatment yields a better prognosis and can prevent complications such as trichobezoar and scarring. [6, 7]
Diagnostic criteria (DSM-5)
The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) placed trichotillomania in the category of obsessive-compulsive and related disorders and noted that it is characterized by recurrent body-focused repetitive behavior (hair pulling) and repeated attempts to decrease or stop the behavior.
The behavior can occur during both relaxed and stressful times, but there is often a mounting sense of tension before hair pulling occurs or when attempts are made to resist the behavior. Some authors have advocated for the distinction between “automatic” pulling occurring during sedentary activities with little awareness and “focused” pulling in response to negative or stressful emotions, in that these different styles may respond to different treatment strategies. [8]
The specific DSM-5 criteria for trichotillomania (hair-pulling disorder) are as follows [9] :
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Recurrent pulling out of one’s hair, resulting in hair loss
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Repeated attempts to decrease or stop the hair-pulling behavior
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The hair pulling causes clinically significant distress or impairment in social, occupational, or other important areas of functioning
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The hair pulling or hair loss cannot be attributed to another medical condition (eg, a dermatologic condition)
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The hair pulling cannot be better explained by the symptoms of another mental disorder (eg, attempts to improve a perceived defect or flaw in appearance, such as may be observed in body dysmorphic disorder)
Pathophysiology
From a dermatologic standpoint, trichotillomania is a form of traumatic alopecia. The trauma to the follicle occurs as a result of the patient’s repetitive hair-pulling behavior. The hair pulling may present in conjunction with other repetitive grooming behaviors, such as nail biting and skin picking.
Trichotillomania results in highly variable patterns of hair loss. The scalp is the most common area of hair pulling, followed by the eyebrows, eyelashes, pubic and perirectal areas, axillae, limbs, torso, and face. The resulting alopecia can range from thin unnoticeable areas of hair loss to total baldness in the area(s) being plucked.
In addition, trichophagia (ingestion of the hair) is common in persons who pull out their hair. This chewing or mouthing behavior can frequently lead to the formation of trichobezoars (ie, hair casts) in the stomach or small intestines. Trichobezoars can result in anemia, abdominal pain, hematemesis, nausea or vomiting, bowel obstruction, perforation, gastrointestinal (GI) bleeding, acute pancreatitis, and obstructive jaundice.
Etiology
The etiology of trichotillomania is largely unknown, though both environmental and genetic causes have been suspected. Explanations that have been proposed for the onset and maintenance of the hair-pulling behavior include the following:
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Coping mechanism for anxiety or stressful events
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Benign habit that developed from a sensory event (eg, itchy eyelash) or another event and resulted in trichotillomania
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Occurrence in conjunction with another habitual behavior (ie, thumbsucking) in young children
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Serotonin deficiency - A link may exist between a deficiency of the neurotransmitter serotonin (5-hydroxytryptamine [5-HT]) and trichotillomania; the hypothesized connection is based on the success of selective serotonin reuptake inhibitors (SSRIs) in treating some people with trichotillomania
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Structural brain abnormalities - On magnetic resonance imaging (MRI), some individuals with trichotillomania have abnormalities of subcortical regions involved in habit generation, inhibitory control, and regulation of affect [10]
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Abnormal brain metabolism - On positron emission tomography (PET), some individuals with trichotillomania have a high metabolic glucose rate in the global, bilateral, cerebellar, and right superior parietal areas
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Genetic susceptibility - DSM-5 cited some evidence that genetic vulnerability plays a role [9] ; trichotillomania occurs more frequently in people with obsessive-compulsive disorder (OCD) and their first-degree relatives
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Disordered reward processing - Preliminary data have suggested that trichotillomania may represent a disorder of altered reward processing within the central nervous system (CNS); a study of reward processing in trichotillomania patients demonstrated altered nucleus accumbens activations and a decreased functional connection between the dorsal anterior cingulate and nucleus accumbens and basolateral amygdala and reward network [13] ; input was through glutamatergic projections, identifying a possible intervention point with agents that modulate glutamate
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Neurodegenerating disease associations - Reports have also suggested a possible association between neurodegenerating diseases (eg, Parkinson disease and dementia [14] ) and trichotillomania in older populations
Epidemiology
United States and international statistics
Although US epidemiologic studies on the prevalence of trichotillomania are rare, it has been estimated that approximately 8 million people have trichotillomania. The overall frequency is probably underestimated, because only persons who present for treatment are counted; denial of the disorder is frequent, and many individuals with the disorder do not seek professional intervention. Further epidemiologic studies are needed.
In a study of college students, approximately 1-2% had past or current symptoms of trichotillomania. [15] The rate fell to 0.6% when patients were restricted to the group having related mental tension and relief; without such restrictions, the rate of hair pulling resulting in visible hair loss was 1.5% for males and 3.4% for females. A survey at a historically Black university (N = 248) found that 6.3% of those surveyed had a history of pulling out their hair. [16]
In the authors’ experience, the number of patients with trichotillomania is approximately 5% of the number of patients with alopecia areata. The incidence of alopecia areata is approximately 50% of all patients presenting with alopecia, and the total number of hair-loss patients is approximately 2% of all dermatologic patients.
Age-, sex-, and race-related demographics
Trichotillomania is frequently a chronic disorder that lasts weeks to decades, with a variable age of onset. Hair-pulling sites may vary with the age of onset: Patients with a very early onset of trichotillomania are more likely to pull eyelashes, whereas those with a later onset are more likely to pull pubic hair. [17] In a study by Walther et al, it was reported that the 27 children in the preschool age group (0-5 y) pulled only from the scalp and that more than half of those in the 5- to 10-year age group children pulled from other body areas in addition to the scalp. [18]
Although empiric data are not available, this condition appears to be substantially more common in children than in adults. In general, prognosis is related to patient age. Children typically have a time-limited disorder, with an excellent prognosis. Adolescents have more severe disease, with a guarded prognosis. Adults, many of whom were diagnosed before reaching adulthood, have a poor prognosis.
With regard to sex-related differences, the younger the patient, the more equal the sex distribution. However, a cross-sectional study of 110 young children (age range, 0-10 y) demonstrated that a female predominance still exists, even among younger patients. [18] In adult groups, most patients are women. In adolescents, girls are affected more often than boys. DSM-5 cited an overall female-to-male ratio of 10:1. [9]
No racial differences in prevalence have been reported. Trichotillomania appears to be equally common in Whites, Blacks, and Asians.
Prognosis
In very young children, the prognosis is excellent; hair pulling that occurs in young children may be described more accurately as a short-term habit disorder. In late childhood and adolescence, the prognosis is usually good but should be considered guarded; the alopecia quite often continues for months or a couple of years and then recurs after a variable time. In adult patients, the prognosis is poor, and permanent recovery is uncommon.
Trichotillomania results in highly variable patterns of hair loss, ranging from small undetectable patches of hair loss to total baldness. Ingestion of the pulled hair can result in trichobezoar formation and subsequent anemia, abdominal pain, hematemesis, nausea or vomiting, bowel obstruction, perforation, GI bleeding, pancreatitis, and obstructive jaundice.
Trichotillomania can become a chronic and persistent condition. Specifically, symptoms of trichotillomania can persist for weeks to decades. Therefore, comprehensive treatment planning is critical and may require consultations with mental health professionals. Treating trichotillomania in children may be difficult because of the low reliability and validity of self-reporting.
Mortality is not reported with trichotillomania.
Most patients with trichotillomania in dermatologic clinics are children and early adolescents. Patients may try to conceal the alopecic area and may have some restrictions in their school activities. In adults, trichotillomania may cause distress and impairment in occupational and social or marital relations. [19]
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Geometric patch of incomplete alopecia in teenage boy.
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Bizarre-patterned lesion covered with short hairs in 11-year-old girl.
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Typical geometric shape trichotillomania in 7-year-old boy. Smooth baldness of scalp surface at this age is rare.
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In eyebrow involvement, characteristic geometric shape is not made.
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Sometimes, alopecia is not circumscribed but simply shows deficient hair volume, as in this 9-year-old girl.
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When entire scalp is involved, trichotillomania resembles keratinization disorder of hairs (eg, monilethrix).
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Tonsure trichotillomania (so named because of similarity to medieval monks' tonsures). In this patient, hair is preserved only in posterior margin of scalp.
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Close-up picture of lesion of usual trichotillomania shows combination of newly growing young hair, broken shafts, comedolike black dots, empty orifices, and vellus or intermediate hairs.
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Contrast card examination helps demonstrate nature of alopecia to parents of children with trichotillomania. It shows broken hairs and newly growing hairs with slender tips among long intact hairs.
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Woman with severe long-standing lesions from trichotillomania.
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Close-up picture of severe long-standing lesion in which hairs are regressed to vellus- or intermediate-type hairs and scalp is rather smooth.
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Histopathologically, trichomalacia (twisted pigmented soft cortex) with catagen follicles is characteristic of trichotillomania with empty follicles.
