Trichoscopic Findings in Pressure Alopecia: Report of Two Cases and Review of the Literature.

Pressure alopecia (PA) is an uncommon type of hair loss due to ischemic changes of the scalp, as a result of prolonged immobilization. Clinically, it often appears within the 1st month of the trigger and tends to resolve spontaneously within 4 months. If the duration of the immobilization is longer, irreversible alopecia can be developed. Trichoscopy is usually nonspecific, being black dots, broken, and dystrophic hairs the most frequent findings. However, yellow dots and thin hairs have also been reported. We herein present two patients with PA, one with a recent development and another one with a long-lasting alopecia. Both of them showed keratotic follicular plugs and thin hairs as the main trichoscopic findings. Copyright:

INTRODUCTION

Pressure alopecia (PA) is a type of hair loss, which normally occurs following prolonged immobilization, such as long-lasting surgeries or hospitalization in intensive care units (ICU).[12] PA usually appears 3–28 days after the trigger, as a painful, swollen, and erythematous area, followed by an abrupt patchy hair loss. Hair tends to regrow spontaneously within 4 months.[3] However, if the injury is more persistent, skin necrosis may appear, and hair loss may be irreversible.[3] The continued pressure on the scalp results in vascular compression and tissue ischemia, which leads to the cessation of the activity of the hair follicle.[1] The duration of pressure seems to be more important than its intensity in the development of PA and its reversibility.[45]

CASES REPORT

Case 1

A 10-year-old girl presented with an alopecic path on the parieto-occipital area lasting for 2 years. She was hospitalized in ICU for 3 days with cranioencephalic trauma, and later with a depressed level of consciousness for 1 month. She developed some crusts after leaving the hospital and hair loss 2 weeks later. Physical examination revealed a 10 cm × 5 cm well-defined alopecic path [Figure 1a], with keratotic plugs. Trichoscopy showed yellow dots, keratotic follicular plugs, and nonpigmented thin hairs [Figure 1b].

Figure 1

(a) Alopecic area with evident keratotic plugs. (b) Trichoscopy showed skin-colored background, with yellow dots (asterisks), follicular plugs (black arrows), and a few thin and nonpigmented vellus hairs (blue arrows).(FotoFinder, polarized light, ×20)

Case 2

A 30-year-old man presented with a 2-month alopecic patch on the occipital area following a 9-h thyroid surgery. He referred that few days later he had a red alopecic patch on the scalp. Two months after the surgery, the alopecia remained and he asked for a dermatologist. Physical examination showed a 5 cm × 2 cm alopecic patch [Figure 2a]. Trichoscopy revealed keratotic plugs, a few thin hairs, reddish background, and a brownish hyperpigmented area [Figure 2b].

Figure 2

(a) Oval-shaped alopecic area. (b) Trichoscopy showed keratotic follicular plugs (black arrows) and several thin and nonpigmented vellus hairs (blue arrows). Thin and short pigmented hairs (red arrows) were also noted. Erythema was noted in the upper part of the patch (black asterisk), whereas a brownish hyperpigmented area was observed in the lower region (blue asterisk). (Dermlite, nonpolarized light, ×10)

DISCUSSION

Trichoscopic features of PA include more commonly nonspecific findings, such as black dots, and broken and dystrophic hairs.[3] Yellow dots have been reported in PA during the early phase, along with black dots and dystrophic hairs; whereas yellow–brown crusts, dilated infundibula, and diffuse circle hairs are noted in the late phase (after 1 month). If scarring happens, loss of follicular ostia and yellow dots may be found.[2] The second patient had follicular plugs but no yellow dots, according to the described signs for PA after 1 month. However, the first patient, who had a long-lasting alopecia, had both yellow dots and dilated infundibula with follicular plugs. The presence of vellus and thin residual hairs has been reported, which may be explained by their lower metabolic rates and/or more superficial insertion of their bulbs than terminal hairs.[1] Interestingly, the most characteristic trichoscopic sign in both patients was the presence of keratotic plugs, whereas black dots and broken hairs were not present.

Trichoscopy of PA may resemble alopecia areata and trichotillomania when erythema and ulceration are absent.[1] Exclamation mark hairs are particular characteristics of alopecia areata, in which keratotic plugs are not seen. In patients with trichotillomania, broken hairs with different lengths may be observed.[2]

Pressure-relieving devices, scalp massage, and repetitive changes of the head position may help to avoid PA.[4] Complete hair regrowth happens in about 90% of cases.[1] However, none of our patients had complete hair recovery. In conclusion, clinical suspicion in PA is particularly important due to the lack of specific trichoscopic signs. Dermoscopy could be useful when the history of pressure is not explicit and for ruling out other diagnoses.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.