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. (J Dermatol Case Rep. 2015; 9(1): 1-5)

Trichoscopy of alopecia areata: An update

“…According to Miteva and Tosti, yellow dots are not present in children because of the underdevelopment of sebaceous glands before puberty. Nevertheless, yellow dots were observed with an incidence rate ranging 40–100% in a number of studies describing trichoscopic findings in alopecia areata in children . Furthermore, a study conducted by Rakowska et al .…”

“…Nevertheless, yellow dots were observed with an incidence rate ranging 40–100% in a number of studies describing trichoscopic findings in alopecia areata in children . Furthermore, a study conducted by Rakowska et al . revealed not only solitary yellow dots, but also clustered yellow dots (defined as three or more yellow dots in adjacent follicular units) in children with alopecia areata.…”

“…These are considered to be the remnants of broken hairs, exclamation mark hairs or tapered hairs . In children, black dots have to be differentiated from rectangular black granular structures that are characteristic of loose anagen syndrome . Black dots predominate in acute alopecia areata with active hair loss .…”

“…However, exclamation mark hairs are also observed in the stable, non‐progressive disease . The proportion of exclamation mark hairs varied 12–71% (mean value, 39%) in patients with alopecia areata . Although exclamation mark hairs are considered as a pathognomonic feature of alopecia areata, they are also observed in other hair diseases such as trichotillomania, tinea capitis, chemotherapy‐induced alopecia and anagen effluvium in the course of a severe intoxication …”

“… The ranges from published articles are given for the trichoscopic features for which the frequency was evaluated. ‡ Mean value was calculated by dividing the total number of patients with a particular feature by the total number of patients in studies reporting the frequency of this feature. …”