RNA sequencing in the skin of non-responders and allergic individuals exposed to p-phenylenediamine
p-Phenylenediamine (PPD) is a strong contact allergen used in hair dye that is known to cause allergic contact dermatitis (ACD). We investigated the effects of PPD exposure on the skin of occupationally exposed subjects with and without clinical symptoms. Overall design: Skin biopsy specimens were collected from 4 patients with mild and 5 patients with severe PPD-related ACD and 7 hairdressers without contact dermatitis on day 4 after patch testing with 1% PPD in petrolatum or just petrolatum.