Sensitization to benzyl salicylate and other allergens in patients with frontal fibrosing alopecia

Abstract

Background: Contact sensitization is frequent among patients with frontal fibrosing alopecia (FFA) (52%-76%).Objective: To evaluate the frequency of sensitization/photosensitization in an FFA population.Methods: A population of FFA patients were patch tested (Spanish Contact Dermatitis Research Group [GEIDAC] baseline; cosmetic and fragrance series), and photopatch tested (sunscreen series).Results: Thirty-six patients (mean age: 64.6 years; 35/36: women) were studied. A history of dermatitis was recorded in 69.4% (frequently involving the face). Overall, 80.5% patients showed positive patch-test reactions. The most frequently positive allergens were nickel sulfate (25%), benzyl salicylate (22%), gallates (16.6%), propolis (16.6%), and limonene hydroperoxides (13.8%). Benzyl salicylate was likely relevant to the dermatitis (labeled on personal care products and most patients reporting clinical improvement with allergen avoidance). Patch tests with sunscreens showed positive reactions to 11 materials (five patients). Photopatch tests were positive in one case. Conclusion:We speculate a possible relationship between sensitization to benzyl salicylate and FFA. Hypothetically, the most likely explanation is that sensitization to benzyl salicylate involving FFA patients is a consequence of increased exposure to it.It is unclear whether allergen avoidance may impact the prognosis of alopecia. However, it seems to significantly improve the patients´quality of life by lessening dermatitis and pruritus. K E Y W O R D S allergic contact dermatitis, benzyl salicylate (CAS no. 118-58-1), fragrance, frontal fibrosing alopecia, gallates, patch tests, photopatch tests, propolis, scarring alopecia, sunscreen 1 | INTRODUCTION Frontal fibrosing alopecia (FFA) is an inflammatory type of alopecia in which lichenoid lymphocytic infiltrates lead to perifollicular fibrosis and irreversible loss of follicles. It mainly concerns the frontal, The authors do not have any conflicts of interest to declare.

Frontal Fibrosing Alopecia: A Review

“…A higher frequency of positive patch test in FFA patients, mainly for fragrances [ 93 ], benzyl salicylate [ 102 ], cobalt, nickel, and potassium dichromate [ 103 ], have been found in different studies, although others do not suggest any association of FFA with photoallergy to several cosmetic-related substances (including chemical sunscreen filters) or titanium dioxide [ 100 , 104 ]. Moreover, the positive patch test may be a consequence of increased exposure to these substances.…”

Response to Letter to the Editor

“…2,[5][6][7] We found frequent sensitization to allergens, such as BS (22%), gallates (16.6%), propolis (16.6%), and limonene hydroperoxides (13.8%) in 36 patients with FFA. 1 Of interest, in some patients, reactions to BS, gallates, and propolis seemed to be concomitant, 1 suggesting a peculiar allergenic profile. Sensitization to gallates and propolis have been described in patients with FFA and lichen planus (LP) pilaris.…”

There is no proven association between sensitization to benzyl salicylate and frontal fibrosing alopecia

“…Consequently, the authors have reported an association between FFA and sensitization to benzyl salicylate. Although the reported patch test positivity to benzyl salicylate in patients with FFA (22%) is higher than that of a comparable regional patch tested population (1.1%), 1 there remain significant doubts regarding this relationship. First, the selection procedure for inclusion in this study is unclear.…”

“…To the Editor, Pastor-Nieto et al 1 report a case series of 36 patients with frontal fibrosing alopecia (FFA) who have undergone patch testing. Based on their observations, they hypothesize that contact sensitization to benzyl salicylate may occur as a cause or consequence of the pathogenic mechanisms underlying this disorder.…”

“…Thus, the strength of any existing association remains uncertain. Subsequently, Pastor-Nieto et al 1 propose several hypotheses to account for their observed association between benzyl salicylate sensitivity and FFA, notably suggesting that benzyl salicylate could be a sole or significant factor in FFA pathogenesis. However, benzyl salicylate is a weak sensitizer and poses a low risk as a contact allergen.…”