894 Comprehensive patch testing in 22 patients with lichen planopilaris

Abstract

Limited studies have identified an association between frontal fibrosing alopecia (FFA) and leave-on facial skin care products. Although debated, allergic contact dermatitis to these personal care products may contribute to the lymphocytic inflammation affecting the hair follicle unit. This case series sought to identify relevant allergens in patients with lichen planopilaris (LPP) and/or FFA who were seen in an alopecia clinic and referred to patch testing. Patients underwent patch testing with the American Contact Dermatitis Society Core Allergen Series I-VIII, Cosmetic and Hairdresser Series in addition to 8 other potential allergens. Patch tests were applied to the back and read at 48 and 96 hours. Equivocal (+/-) reactions were not included in the results. Between January 2018 and December 2018, 22 female patients with a mean age of 60 years old (range 30-75) underwent patch testing. The majority of patients were Caucasian (95%) and either peri- or post-menopausal (90%) with histological and clinical evidence of LPP (55%), FFA (36%), or LPP/FFA overlap (9%). In total, 77% of patients demonstrated clinically relevant allergens found in cosmetics and personal care products applicable to the head and neck. The mean number of relevant positive allergens was 2 (range 1-8) with more than one-fourth of patients having 4 or more relevant allergens. Half of the patients (50%) had allergens relevant to both facial skin and hair care products. Fragrance mix and fragrance cross reactors (23%), ammonium persulfate (18%), MI and MCI/MI (18%), and dodecyl gallate (18%) represented the most common relevant allergens in these patients. The overall prevalence of patients with relevant positive allergens in this case series (77%) was higher than previous studies which reported on all positive allergens in Brazilian (59%) and British patients (53%) with FFA exclusively. Given the prevalence of relevant contact allergens in females with LPP/FFA, clinicians may consider patch testing for this patient population.