Trichotillomania
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Direct answer
Trichotillomania is a compulsive disorder in which a patient repeatedly pulls out their own hair, producing patchy and irregular hair loss with broken hairs of varying length. It is classified among obsessive-compulsive and related disorders, and the scalp is the commonest site. The first-line treatment is behavioural therapy, most often habit reversal training, rather than topical or systemic drugs.
What you must remember
- Behaviour: repeated hair pulling that the patient finds hard to resist, often with rising tension before pulling and relief afterwards.
- Bizarre pattern: irregular patches with hairs of different lengths, rather than the smooth, round patches of alopecia areata.
- Sites: the scalp is commonest, but eyebrows, eyelashes and the beard may also be pulled.
- Trichoscopy: "flame" hairs, tulip hairs, broken shafts and hairs of varying length support the diagnosis.
- Exclamation mark hairs: a feature of alopecia areata, not of trichotillomania, so their absence is a useful clue.
- Classification: DSM-5 places the disorder among obsessive-compulsive and related disorders, while ICD-10 lists it under habit and impulse disorders.
- Treatment: habit reversal training with competing response training is first-line, and N-acetylcysteine has some supporting evidence as an add-on.
- Comorbidity: anxiety, depression and other body-focused repetitive behaviours often coexist, so mood should be screened.
Comparing patchy hair loss patterns
Patchy scalp hair loss has several common causes, and the history and pattern usually separate them quickly. The table compares the three disorders most often confused in exam stems.
| Feature | Trichotillomania | Alopecia areata | Traction alopecia |
|---|---|---|---|
| Pattern | Irregular, bizarre patches | Round or oval smooth patches | Loss along the hairline margins |
| Hair shafts | Broken hairs of varying length | Exclamation mark hairs at the edge | Broken hairs at the margins from tight styling |
| Pulling | Present, often denied by the patient | Absent | Caused by styling rather than behaviour |
| Nails | Normal | Pitting in some patients | Normal |
| Key clue | Behaviour and trichoscopy | Dermoscopy and biopsy | Stopping the traction |
Trichotillomania is diagnosed on history and pattern, so the examiner should ask about pulling directly, because patients often deny it. Traction alopecia is distinguished by its marginal distribution and a link with tight hairstyles.
Hair of varying length within one patch is a strong clue to pulling, whereas the broken hairs in alopecia areata are usually of similar short length at the edge. A biopsy is rarely needed when the history and trichoscopy are typical.
Where the exam tries to catch you
Stems on hair loss often test whether you connect a patchy pattern with a behavioural cause rather than an autoimmune one.
- Trap: calling trichotillomania alopecia areata because the patches are patchy and bald. Correct: trichotillomania has irregular patches and broken hairs of varying length, whereas exclamation mark hairs are specific to alopecia areata.
- Trap: treating the condition with topical steroids and expecting a cure. Correct: the cause is behavioural, so habit reversal therapy and recognition of triggers form the core treatment.
- Trap: ignoring anxiety or depression in a patient with hair pulling. Correct: psychiatric comorbidity is common, and assessment should include mood and anxiety symptoms.
Frequently asked questions
How does trichotillomania differ from alopecia areata on examination?
Trichotillomania produces irregular patches with hairs of varying length and broken shafts, whereas alopecia areata gives smooth round patches with exclamation mark hairs at the edges. A careful history about pulling behaviour is the key difference, since patients with trichotillomania may deny it.
What is habit reversal training in trichotillomania?
Habit reversal training is a behavioural therapy that teaches the patient to recognise the urge to pull and then perform a competing response, such as clenching the fist. It is first-line therapy for trichotillomania and is delivered by a trained therapist.
Which trichoscopic features support a diagnosis of trichotillomania?
Trichoscopy in trichotillomania shows hairs of varying length, broken shafts, "flame" hairs and tulip hairs, which together support the diagnosis. Alopecia areata shows exclamation mark hairs and black dots instead, which helps separate the two disorders.
Why must trichotillomania be considered in a child with patchy hair loss?
Children with patchy hair loss may pull their hair when anxious or bored, and the pattern is easily mistaken for alopecia areata or tinea capitis. A fungal test and a careful behavioural history are therefore needed before the diagnosis is settled.