Trichoscopy of Focal Alopecia in Children - New Trichoscopic Findings: Hair Bulbs Arranged Radially along Hair-Bearing Margins in Aplasia Cutis Congenita

Abstract

Purpose: To establish whether trichoscopy can be useful in the differential diagnosis of patchy alopecia in children.

Procedures: The study was a retrospective analysis (2012-2015) and included 68 patients under 6 years of age. The inclusion criteria were age and the presence of 1-3 alopecia patches. A total of 124 alopecia patches were examined with the use of a videodermoscope: 102 alopecia areata, 8 tinea capitis, 6 trichotillomania, 3 temporal triangular alopecia and 5 aplasia cutis congenita.

Results: In all aplasia cutis congenita lesions, trichoscopy revealed elongated hair bulbs visible through the semitranslucent epidermis, seen at the hair-bearing margin and radially arranged. Hair regrowth [upright regrowing hairs (44%), circular hairs (23%) and vellus hairs (20%)] was observed in the majority of alopecia areata patches. For triangular alopecia, upright regrowing hairs (100%; 3/3), vellus hairs (100%; 3/3) and circle hairs (33%; 1/3) were seen inside the alopecia patch.

Conclusion: Trichoscopy is a useful technique for the differential diagnosis of patchy alopecia in children. A novel finding in this study indicates that radially arranged hair bulbs visible through the translucent epidermis are characteristic of nonbullous type aplasia cutis congenita.

Keywords: Alopecia areata; Alopecia trichoscopy; Aplasia cutis congenital; Dermoscopy.

Fig. 1

ACC (×20). At the edge of patchy alopecia radially arranged hair bulbs are visible. These hair bulbs are directed into the middle of the lesion, with dark pigmented proximal ends (typical for the anagen phase). There are no follicular openings at the center of the lesion, but a vascular network resembling a spider's web is seen.

Fig. 2

Trichotillomania (×20). Specific features of trichotillomania can be seen: irregularly broken hairs, coiled hairs, v-sign and circle hairs.

Fig. 3

Alopecia areata (×20). Exclamation mark hairs and coiled hairs are visible.

Fig. 4

TTA (×20). Short upright regrowing hairs cover the area of alopecia. Terminal hairs on the outskirts of the lesion can be seen.

Fig. 5

Key trichoscopic findings for patchy alopecia (alopecia areata, tinea capitis, ACC, TTA and trichotillomania) in pediatric trichology.