Plastic-associated chemicals on vulvar skin - Dermal exposure and effects on keratinocytes

Several plastic-associated chemicals (PACs), such as bisphenols and phthalates, are endocrine disruptors. There is little research concerning PAC presence on vulvar skin or in underwear fabric, which remains in prolonged daily contact with thinly keratinised regions of the vulva. We measured PAC concentrations in commercially purchased women's underwear and detected several PACs in 100% of samples; polyamide fabric had higher concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), and bisphenol S (BPS) compared to cotton. Di(2-ethylhexyl) phthalate (DEHP) was the dominant PAC in both fabric types. We collected skin swabs from the thighs and the outer vulva of adult women volunteers and investigated PAC distribution frequencies and concentrations. Bisphenol A (BPA) and DMP were not detected while BPS, DEP, DEHP, and di-n-decyl phthalate (DnDP) were detected in ∼ 50% to 100% of samples. There was a significant positive correlation between PAC lipophilicities and molecular weights with concentrations in skin-swabs. Estimated daily exposure (ng/kg bw/day) calculated for individual PACs did not exceed established limits for human exposure. BPA and DEHP decreased epidermal thickness in 3D keratinocyte-fibroblast organotypic raft co-cultures. This is the first report on PACs on vulvar skin and suggests that further robust studies to clarify vulvar dermal PAC absorption and links to vulvar dermatoses are warranted.