Patch Testing to Paraphenylenediamine: The North American Contact Dermatitis Group Experience (1994-2018)

Dermatitis. 2023 Nov-Dec;34(6):536-546. doi: 10.1089/derm.2023.0140. Epub 2023 Jul 31.

Abstract

Background/Objectives: Paraphenylenediamine (PPD) is an aromatic amine dye that may cause allergic contact dermatitis. This study examines the epidemiology of allergic patch test reactions to PPD. Methods: This retrospective analysis characterizes individuals tested to PPD (1% petrolatum) by the North American Contact Dermatitis Group (1994-2018). Demographics and dermatitis site(s) were compared between PPD-allergic and PPD-negative patients. PPD reactions were analyzed by reaction strength, clinical relevance, occupational relatedness, and source as well as coreactivity with structurally related compounds. Results: Of 54,917 patients tested to PPD, 3095 (5.6%) had an allergic patch test reaction. Compared with PPD-negative patients, PPD-allergic patients had significantly greater odds of age >40 years (odds ratio [OR] 1.55 [95% confidence interval; CI 1.43-1.69]) and female gender (OR 1.52 [95% CI 1.41-1.66]), but lower odds of being White (OR 0.66 [95% CI 0.60-0.71]). The most common primary anatomic sites of dermatitis were face (25.5%), hands (21.9%), and scattered/generalized pattern (15.5%). Over half (55.3%) of PPD reactions were ++ or +++ at the final reading and 60.9% were currently relevant. Common exposure sources included hair dye (73.5%) and clothing/shoes/apparel (3.9%). Occupationally related reactions occurred in 8.3%, most commonly in hairdressers/cosmetologists (72.8%). The most common coreactions were benzocaine (11.3%), N-isopropyl-N'-phenyl-p-phenylenediamine (6.7%), disperse dye mix (6.5%), and black rubber mix (5.1%). Conclusions: The 24-year percentage of allergic reactions to PPD was 5.6%. PPD allergy was associated with female gender and age >40 years. PPD allergic patients were less likely to be White. Allergic reactions were usually clinically relevant and hair dye was the most frequently identified source.

MeSH terms

  • Adult
  • Dermatitis, Allergic Contact* / diagnosis
  • Dermatitis, Allergic Contact* / epidemiology
  • Dermatitis, Allergic Contact* / etiology
  • Female
  • Hair Dyes* / adverse effects
  • Humans
  • North America
  • Patch Tests / adverse effects
  • Phenylenediamines / adverse effects
  • Retrospective Studies

Substances

  • 4-phenylenediamine
  • Hair Dyes
  • Phenylenediamines
  • N-isopropyl-N-phenyl-4-phenylenediamine