Frontal Fibrosing Alopecia

Abstract

Frontal Fibrosing Alopecia (FFA) is a progressive lymphocytic scarring alopecia characterized by a band-like area of frontal or frontotemporal hairline recession most commonly in postmenopausal women. Eyebrows, eyelashes, and sideburns as well as limb, axillary, moustache, beard, and pubic hair involvement can be present too. The dermatological literature is currently exploding in papers on FFA, therefore this chapter aims to summarize curious/novel trichoscopic-pathologic correlations. The pathogenesis of FFA is unclear but considered to be overlapping with lichen planopilaris (LPP) (see Lichen Planopilaris). Recent genome-wide association study showed that FFA is a genetically predisposed immuno-inflammatory disorder driven by HLA-B*07:02 allele on chromosome 6. There are three most common clinical patterns: (1) a linear uniform band of hair loss of the frontal hairline, (2) an irregular or zigzag pattern at and behind the frontal hairline, and (3) a ‘pseudo-fringe-sign pattern’ with hair loss behind the preserved frontal hairline. Several unusual variants have been identified including: (1) androgenetic alopecia-like pattern, (2) cockade-like pattern, and (3) ophiasis-like pattern (Figure 14.1). Other unusual variants include occipital FFA, patchy FFA and upsilon-like FFA. Figure 14.1 The 3 unusual clinical subtypes in FFA: (A) AGA-like pattern, (B) cockade, and (C) ophiasis pattern. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_1.tif"/> Two curious associations: Lichen planus pigmentosus (LPPigm) is more prevalent in FFA patients with darker skin, can precede the diagnosis and presents as brown macules coalescing into patches on the face and upper trunk; (yellow) facial papules are skin-colored monotonous papules on the face, usually the temporal and malar area. Both features have been found more prevalent among premenopausal and Hispanic/Latino women (Figure 14.2). Figure 14.2 Two curious associations with FFA: (A) LPPigm (diffuse brown patches on face, note involvement of the upper eyelids) and (B) yellow facial papules. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_2.tif"/> On trichoscopy the features are similar to LPP (see Chapter 13). Some additional or distinct features include: Loss of vellus hairs in the hairline (Figure 14.3A): while this is the rule, there can be exceptional/early cases of retained vellus hairs (Figure 14.3B) Figure 14.3 99Loss of vellus hairs in the frontal line in FFA (A) compared to normal hairline (B, ×20). (C) FFA with preserved vellus hairs but peripilar casts in the immediate vicinity behind (×10). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_3a.tif"/> https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_3b.tif"/> 100Lack of tufts (compound hairs) compared to LPP (unpublished data; personal communication with Dr. Giselle Martins); the histologic correlation to this is that in FFA there are usually “eyes” and not “goggles” (see Figure 14.10) Peripilar casts are usually more subtle and absent in the sideburns (Figure 14.4) Figure 14.4 Preauricular areas/sideburns show lack of peripilar casts but transparent proximal emergences (×20). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_4.tif"/> Vessel net (this corresponds to the superficial vascular plexus with its branching vessels visualized by trichoscopy due to the atrophy of the skin) (Figure 14.5) Figure 14.5 Vessel net in FFA (×40). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_5.tif"/> Peripilar hypopigmented halo (Figure 14.6) Figure 14.6 Peripilar hypopigmented halo in FFA (×10). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_6.tif"/> Eyebrow trichoscopy can show yellow dots, dystrophic hairs, gray dots and hairs growing in different directions (Figure 14.7). Trichochorrhexis nodosa can also be observed most likely due to aggressive topical application (personal observation) (Figure 14.8) Figure 14.7 (A) Eyebrow trichoscopy in FFA: yellow, gray dots and hair growing in distinct directions. (B) Dystrophic hairs: this patient has not plucked the eyebrows within last 6 months (×40). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_7.tif"/> Figure 14.8 (A) Trichorrhexis nodosa of the eyebrows in FFA. The patient has been rubbing pimecrolimus cream into the affected eyebrows (B, ×20). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_8.tif"/> LPPigm: folliculocentric blue-gray dots in circles, speckled dots, and rhomboid structures (Figure 14.9). In melasma the pigment is not folliculocentric Figure 14.9 (A) LPPigm on the forehead extending to the frontal hairline in FFA shows blue-gray dots in circles (×50) which is a clue to (B) periappendigeal involvement with accentuation of melanophages. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig14_9.tif"/>