Approach Considerations
The Trichotillomania Scale for Children (TSC) is a child and parent report that may be used to assess symptom severity and impairment. [24]
Trichography (ie, microscopic examination of plucked hairs) can help verify the diagnosis of trichotillomania. Findings vary according to the area examined. Where the hairs are all short with tapered tips (regrowing hairs), the trichogram may show all anagen roots (telogen count, 0). In other areas, especially those showing broken shafts of various lengths, an increased number of club hairs (>20%), and even exclamation-mark hairs typical of alopecia areata, [25] can be seen.
Creation of a “hair growth window” by shaving an involved area weekly and observing for growth can help to confirm a diagnosis of trichotillomania. The area demonstrates normal, dense regrowth as hairs are too short to be manipulated or pulled.
Ultrasonography and computed tomography (CT) may be useful in detecting trichobezoar formation that can result from swallowing or ingesting plucked hairs in children with trichotillomania.
Histologic procedures may aid in the diagnosis of suspected trichotillomania in children. Punch biopsy may be used to verify a suspected diagnosis of trichotillomania. Melanin pigment casts and granules in the upper hair follicles and infundibulum of hair shaft are characteristic (see Histologic Findings).
Histologic Findings
In most cases, a clinical diagnosis, based on an inspection of the lesion and an appropriate patient history, is sufficient. Hairs collected by the patient can be examined. Trichotillomania demonstrates anagen hairs, telogen effluvium demonstrates catagen hairs, and alopecia areata demonstrates tapered fractures.
Occasionally, however, biopsy is needed to differentiate trichotillomania from alopecia areata. Biopsy findings of trichotillomania overlap significantly with those of alopecia areata and syphilis. Scalp biopsy specimens are best interpreted by someone with considerable expertise.
Multiple sections, either vertically or transversely oriented, are recommended to observe characteristic findings, especially because both may show numerous catagen hairs and pigment casts. In general, the biopsy specimen should be taken from a new lesion. The most frequent findings are empty anagen follicles (especially in transverse sections), increased numbers of noninflamed catagen follicles, and pigment casts in hair canals, with the latter two findings also present in alopecia areata. The presence of twisted linear pigment in the cortex (zip sign) or circular, central aggregation of pigment surrounded by the inner root sheath (button sign) demonstrate a traumatic cause and can help differentiate the two conditions. [26] There may be hemorrhage in the surrounding dermis from trauma with plucking and scarring over the long term.
Trichomalacia (incompletely keratinized, soft, distorted, and pigmented hair shafts) and bizarre fractured hair shafts are fairly specific for trichotillomania (see the image below).
Histopathologically, trichomalacia (twisted pigmented soft cortex) with catagen follicles is characteristic of trichotillomania with empty follicles.
It should be kept in mind that increased numbers of catagen hairs and pigment casts within hair canals may also be seen in persons with alopecia areata or syphilis, as well as in those with trichotillomania. Care should be taken to search for clues to the diagnosis of alopecia areata or syphilis, such as peribulbar lymphoid infiltrate or peribulbar eosinophils.
Lymphocytes, pigment, and eosinophils within fibrous tract remnants are also associated with alopecia areata and syphilis and may be helpful clues to the correct diagnosis. Plasma cells are a common sign of syphilis, but are not specific. In biopsy specimens from the occipital scalp, plasma cells are common, regardless of the etiology of the hair loss.
Because both trichotillomania and chronic traction alopecia are the result of applied external force, the resulting histopathologic pictures are similar and sometimes identical.
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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 a 7-year-old boy. Smooth baldness of scalp surface at this age is rare.
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In eyebrow involvement, the 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 its similarity to medieval monks' tonsures). In this patient, hair is preserved only in posterior margin of her 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 the 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.
