Patch testing and contact allergen avoidance in patients with lichen planopilaris and/or frontal fibrosing alopecia: A cohort study

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

“…Gallates, previously described to be frequent among FFA patients, 5 were also frequently positive in our series.…”

“…In the same way, benzyl salicylate may cross react with Myroxylon pereirae, which could explain the positive reactions to it in some of our patients as well as in previously published series. [1][2][3][4][5] The association of benzyl salicylate and octyl gallate is less clear. One possible explanation is the exposure to both in a common source (cosmetics, food, or other).…”

“…1 After this research, other studies in different countries also found frequent contact sensitization among patients with FFA (up to 76%) (Online supplemental Table S1). [2][3][4][5] In a recent article by Prasad, a surprisingly high frequency of sensitization to gallates as well as to other allergens was found. 5 To evaluate the frequency of sensitization/photosensitization, the most frequent positive allergens and the frequency of clinical history of dermatitis among an FFA population the following retrospective analysis was performed.…”

A Cell Membrane-Level Approach to Cicatricial Alopecia Management: Is Caveolin-1 a Viable Therapeutic Target in Frontal Fibrosing Alopecia?

“…The association of leave-on cosmetics such as sunscreens with FFA is increasingly being proposed in the field [ 6 , 26 , 28 ]. For example, a higher frequency of sunscreen usage and positive patch tests to sunscreen ingredients in women with FFA has been reported by Moreno-Arrones et al and Prasad et al [ 27 , 29 ]. In addition, Kidambi et al [ 28 ] found a significant relation between FFA and leave-on facial products, such as moisturizing creams and sunscreens in men.…”

“…In general, topical application of creams/lotions tends to penetrate the hair canal until the level of the bulge, which would explain why the intensive and increasingly widespread use of these leave-on cosmetics would affect primarily the bulge and might weaken its relative IP, resulting in inflammation, which in turn could facilitate pathological EMT of bulge eSCs—two key mechanisms in the primary pathobiology of FFA and Lichen planopilaris (LPP) [ 6 , 8 ]. Though this association has been disputed [ 30 , 31 ], it is interesting to note that many of these products contain allergens (gallates, linalool, fragrance mix), which could be associated with the disease activity in patients with FFA and LPP: after at least 3 months of allergen avoidance, 70% of patients have decreased scalp erythema on examination [ 29 ]. Most interestingly, some of these allergens are also odorants, which may be important since selected odorants can indeed regulate human HF growth by stimulating defined olfactory receptors [ 32 , 33 ].…”