Pseudo "fringe sign" in frontal fibrosing alopecia^*

Dear Editor,

Since its description in 1994 by Kossard, frontal fibrosing alopecia (FFA) has been intensively studied, with new features described at every moment.^1-4

Recently, Pirmez et al. described the pseudo "fringe sign", an atypical presentation of the disease, which resembled traction alopecia (TA).⁵ However, the patients presented with features of FFA, scarring alopecia and facial papules or lichen planus pigmentosum, as well as loss of eyebrows and body hairs. The true "fringe sign" is described in TA, in which the hairs of the implantation region are spared after traction. In principle, this difference would help in the differential diagnosis between TA and FFA.

We describe here two cases of patients with FFA presented with pseudo "fringe sign".

The first case was a 54-year-old female patient with hair thinning in the frontotemporal region for about one year, with retained hairs along the frontal implantation line (Figure 1). She denied hair pulling. There was no superciliary alopecia at first, but the condition progressed to the loss of eyebrows and body hair. After a biopsy, we reached the clinical and histological diagnosis of FFA (Figure 2). Considering that lichen planopilaris (LPP) and FFA have indistinguishable histological features, the clinical evolution favored FFA.

Figure 1
Clinical case 1 -Plaques with alopecia in the frontal region sparing the implantation hairline. Dermoscopy of the hairline evidencing the presence of vellus hair in the anterior region, absence of hairs with central erythema and posterior terminal hairline with discrete follicular hyperkeratosis

Figure 2
Vertical cut revealing lymphomononuclear and perifollicular inflammatory cell infiltration at the protuberance and infundibulum levels (Hematoxylin & eosin, X10). Horizontal cut showing lichenoid and lymphomononuclear inflammatory cell infiltration attacking the hair follicle (Hematoxylin & eosin, X100)

The second case was a 46-year-old female patient with complaints of frontal hair loss for about one year and loss of eyebrows hair in the last two years, as well as facial skin-colored papules for about six months (Figure 3). The patient had recently noticed a progressive decrease of axillary hairs. At the initial examination, we observed thinning eyebrows and alopecia in the frontal region, with sparing of the implantation hairline. Frontal biopsy was compatible with FFA, corroborating our clinical diagnosis. Figure 3C shows the evolution of the clinical features, compatible with FFA.

Figure 3
Clinical case 2 -Plaques with alopecia in the frontal region sparing the implantation hairline (A, arrow) and rarefaction of the eyebrows (B). Evolution of this case with increased alopecia areas two years later, already affecting the implantation line (C)

As already reported by Pirmez et al. , although the pseudo "fringe sign" can occur in patients with FFA, biopsies show the characteristic pattern of LPP, which may make diagnosis challenging.⁵ In the reported cases, the presence of facial papules and thinning eyebrows contributed to the diagnosis of FFA, in detriment of LPP with alopecia plaques. In addition, the loss of vellus hair in the frontal region was not observed initially, but a loss after the frontal implantation line, affecting the terminal hairs of that region. Unlike TA, this fringe slowly becomes more rarefied, eventually leading to some vellus hair loss in the region in a later phase, with a scarring, shiny appearance and absence of follicular ostia to trichoscopy.

A study with a greater number of reported cases of this clinical presentation could help explain this type of manifestation, its etiopathogenic implications, and the immune response involved, which would help in therapeutic decisions.

• *
  Work performed at Hospital do Servidor Público Municipal de São Paulo - São Paulo (SP), Brazil
• Financial support: None.

REFERENCES

• ¹
  Kossard S. Postmenopausal frontal fibrosing alopecia. Scarring alopecia in a pattern distribution. Arch Dermatol. 1994;130:770-4.
• ²
  Donati A, Molina L, Doche I, Valente NS, Romiti R. Facial papules in frontal fibrosing alopecia: evidence of vellus follicle involvement. Arch Dermatol. 2011;147:1424-7.
• ³
  Pirmez R, Donati A, Valente NS, Sodré CT, Tosti A. Glabellar red dots in frontal fibrosing alopecia: a further clinical sign of vellus follicle involvement. Br J Dermatol. 2014;170:745-6.
• ⁴
  Pirmez R, Duque-Estrada B, Donati A, Campos-do-Carmo G, Valente NS, Romiti R, et al. Clinical and dermoscopic features of lichen planus pigmentosus in 37 patients with frontal fibrosing alopecia. Br J Dermatol. 2016;175:1387-1390.
• ⁵
  Pirmez R, Duque-Estrada B, Abraham LS, Pinto GM, de Farias DC, Kelly Y, et al. It's not all traction: the pseudo 'fringe sign' in frontal fibrosing alopecia. Br J Dermatol. 2015;173:1336-8.

Publication Dates

• Publication in this collection
  Nov-Dec 2017

History

• Received
  12 Oct 2016
• Accepted
  19 Mar 2017