CD11 Patch testing in vulval dermatoses

Abstract

Abstract Patch testing is an important tool in the investigation of patients with vulval dermatoses, with a significant impact on patients with a relevant identifiable allergen. There has been little research conducted in this area, with small studies suggesting a higher rate of positivity in anogenital dermatoses (39–78%) vs. patch testing in female patients generally (35–40%) (Woodruff CM, Trivedi MK, Botto N, Kornik R. Allergic contact dermatitis of the vulva. Dermatitis 2018; 29:233–43). There is also a high rate of clinically relevant results (13–49%) (Vandeweege S, Debaene B, Lapeere H, Verstraelen H. A systematic review of allergic and irritative contact dermatitis of the vulva: the most important allergens/irritants and the role of patch testing. Contact Dermatitis 2023; 88:249–62). The aetiology of this increased rate of allergic dermatitis at this site can be attributed to a number of factors. This includes intrinsic immunological characteristics of the vulval skin, local elements including infection and urine exposure, as well as external behavioural factors. There is a lack of site-specific guidance in light of this propensity of allergic contact dermatitis in vulval dermatoses. This review examined 54 patient records retrospectively at the University Hospital North Durham from 2016 to 2021 and prospectively from July to December 2022 referred for patch testing with vulval symptoms. Forty-eight patients were included with an average age of 51 years. Itch (48%) and discomfort or soreness (28%) were the main symptoms for which patients were referred. The most frequently requested patch test batteries after the British Standard Battery were medicaments, then cortico­st­eroid. The overall positivity of this cohort was 73%, in line with the available literature. The most common allergens were nickel, followed by fragrances. Of the patients with positive patch tests, 48% were relevant. Forty per cent had a partial response on withdrawal of the allergen, and 8% had complete response. Given the psychosocial impact of vulval pruritus and discomfort and the high positivity of patch testing in these patients, further population-based research is warranted to standardize patch testing in vulval dermatoses. Additionally, a low threshold for referral for patch testing should be considered to identify any element of allergic contact dermatitis in patients with recalcitrant vulval symptoms.