Trichoscopy findings in loose anagen hair syndrome: rectangular granular structures and solitary yellow dots

Abstract

Background: Loose anagen hair syndrome (LAHS) is typically diagnosed in girls older than 2 years who present with hair that "will not grow". Hair microscopic examination shows absent inner and outer root sheaths, ruffling of the cuticle on the proximal hair shaft and deformed pigmented anagen bulbs.

Objective: The aim of the study was to assess whether there are characteristic trichoscopic features favoring the diagnosis of LAHS.

Patients and methods: Eighty nine children patients were included into the study (24 girls with LAHS, 25 with alopecia areata, 20 with telogen effluvium and 20 healthy children). In all groups trichoscopy was performed. Trichoscopy images were analyzed for abnormalities in the hairs shafts, the hair follicle openings and the interfollicular area.

Results: Dirty dots were present in all groups. A unique feature of LAHS was the presence of rectangular black granular structures which differs from dense black dots seen in patients with alopecia areata. This feature was observed in 71% of patients with LAHS. Follicular units with single hairs constituted 92,9% of hair units in these patients (65,5% in telogen effluvium and 53% in the control group). Solitary yellow dots were found in 50% of patient with LAHS and in 24% of patients with alopecia areata, but was not found in control group or in patients with telogen effluvium.

Conclusion: The trichoscopy features favoring the diagnosis of LAHS are: rectangular black granular structures, solitary yellow dots and major predominance of follicular units with single hairs.

Keywords: alopecia; dermatoscopy; dermoscopy; hair; hair loss.

Figure 1

Microscopic hair examination in loose anagen syndrome reveals absent inner and outer root sheaths, ruffling of the cuticle on the proximal hair shaft (floppy sock appearance), and deformed pigmented anagen bulbs. (x10)

Figure 2

Trichoscopy in loose anagen hair syndrome shows black rectangular features with granular structure (A,B; red arrows) and solitary yellow dots seen by trichoscopy in loose anagen hair syndrome (B; green arrow). (x70)

Figure 3

In alopecia areata trichoscopy reveals black dots which are dense in structure (red arrows). (x70)

Figure 4

Black rectangular features and solitary yellow dots seen by trichoscopy in loose anagen hair syndrome. (x20)

Figure 5

Easily pull out hair with rectangular anagen bulb in loose anagen syndrome seen by trichoscopy (red arrow). Pig-tail hairs are sometimes seen as a result of hair regrowth.