Frontal fibrosing alopecia severity index: A trichoscopic visual scale that correlates thickness of peripilar casts with severity of inflammatory changes at pathology

Martínez-Velasco MA, Vázquez-Herrera NE, Misciali C, Vincenzi C, Maddy AJ, Asz-Sigall D, Tosti A. Frontal fibrosing alopecia severity index: a trichoscopic visual scale that correlates thickness of peripilar casts with severity of inflammatory changes at pathology. Skin Appendage Disord. 2018;4:277-80

Abstract

Frontal fibrosing alopecia (FFA) is a scarring alopecia that mainly affects postmenopausal women which comprises recession of the frontotemporal hairline and eyebrow loss. Current techniques to assess this disease are limited, and it is therefore very important to develop a non-invasive technique to assess FFA activity to monitor treatment response. The purpose of this study is to provide a standardised and objective method to assess FFA activity. To this end, the correlation between trichoscopy and pathological features (degree of lymphocytic infiltration) in 20 dermoscopy-guided biopsies of FFA was evaluated. At trichoscopy, the peripilar casts were split into three levels of severity according to their thickness. The trichoscopic visual scale was validated by seven dermatologists. Interobserver and intraobserver agreement was assessed using the Kendall Tau-b coefficient, and the results showed a strong correlation between the severity of peripilar casts at trichoscopy and the degree of lymphocytic infiltrate. It was concluded that the trichoscopic visual scale allows non-invasive assessment of scalp inflammation in FFA in different scalp regions and therefore provides optimal guidance for treatment.

Introduction

The incidence of frontal fibrosing alopecia (FFA) is increasing and prompt treatment is important to prevent progression to advanced stages.However, assessing the efficacy of the treatment is difficult as disease progression is slow and there are no objective methods for evaluating disease activity. Perifollicular erythema was proposed as a sign of activity, but it can persist in patients who do not present further recession of the hairline after treatment.

FFA activity assessment techniques include scalp biopsies and frontal hairline measurements using the Frontal Fibrosing Alopecia Severity Index (FFASI). However, scalp biopsies are invasive and cannot be repeated at each visit, whilst FFASI relies on best-fit models without evaluating the disease at a microscopic level.

Currently, trichoscopy has proven useful in evaluating the FFA activity, progression, and treatment response. Reported FFA outcomes include loss of follicular openings, loss of vellus hairs, erythema and peripilar casts, black dots, broken hairs, and pili torti.

Peripilar casts are defined as concentrically arranged scales encircling the emerging hair shafts.

As no previous studies had been carried out to assess the correlation between peripilar casts and the severity of the lymphocytic infiltrate in FFA, this study aimed to correlate them using dermoscopy-guided scalp biopsies.

Methods

This study was performed in 2 steps. In the first step, the correlation between trichoscopic and pathological outcomes were evaluated in 20 dermoscopy-guided 4-mm punch biopsies of FFA.

The degree of lymphocytic infiltrate was classified as mild (<5 lymphocytes/field/40×), moderate (5-10 lymphocytes/field/40×), or severe (>10 lymphocytes/field/40×).

At trichoscopy, the severity of the peripilar casts was classified according to their thickness, using the Tricholab software of Fotofinder systems®. Cast thickness corresponds to the distance of the hair axis to the farthest external affected point on the scalp and was considered as mild/thin (grade 1; <0.2 mm), moderate/thin to thick (grade 2; 0.2–0.44 mm), or severe/thick (grade 3; >0.44 mm).

The second part of the study consisted of validating the trichoscopic visual scale in a clinical setting. The trichoscopic images were verified by seven dermatologists with special interest in hair diseases.

Concordance was assessed using the Kendall Tau-b and Spearman test and classified as very poor when less than 0.20; 0.21–0.40, poor agreement; 0.41–0.60, regular agreement; 0.61–0.80, good agreement; and 0.81–0.99, excellent agreement.

Results

Correlation between hair cast thickness at trichoscopy and degree of lymphocytic infiltration was highly significant (Kruskal-Wallis p <0.0001, Spearman correlation of 0.905, p <0.0001), in other words, there is a strong correlation. Moreover, concordance between different observers was high, particularly for grade 3 (thickness >0.44mm).

Conclusion

The Frontal Fibrosing Alopecia Severity Index (FFASI) is the tool available to monitor FFA cicatricial progression, but not to measure the inflammatory activity of the disease.

This study identifies a strong correlation between the thickness of peripilar casts and the degree of lymphocytic infiltration in dermoscopy-guided biopsies.The proposed severity grading index of peripilar casts can be utilised to visually assess FFA activity in different scalp areas, which is important to select the areas that need intralesional infiltration and for follow-up of the treatment.

A limitation of this study is that it did not include scalp areas with advanced scarring.

The opportunity presents itself for further studies that could establish a parallel score to the FFASI scale.

Reference

Martínez-Velasco MA, Vázquez-Herrera NE, Misciali C, Vincenzi C, Maddy AJ, Asz-Sigall D, Tosti A. Frontal fibrosing alopecia severity index: a trichoscopic visual scale that correlates thickness of peripilar casts with severity of inflammatory changes at pathology. Skin Appendage Disord. 2018;4:277-80.
Available at: https://doi.org/10.1159/000487158