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Original Investigation
November 3, 2021

Importance of Supplemental Patch Testing Beyond a Screening Series for Patients With Dermatitis: The North American Contact Dermatitis Group Experience

Author Affiliations
  • 1Department of Dermatology, Park Nicollet Health Services, Minneapolis, Minnesota
  • 2Department of Dermatology, University of Minnesota, Minneapolis
  • 3Department of Dermatology, Minneapolis Veterans Affairs Medical Center, Minneapolis, Minnesota
  • 4University of Minnesota Medical School, Minneapolis
  • 5Division of Dermatology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
  • 6Division of Dermatology, University of Ottawa, Ottawa, Ontario, Canada
  • 7Department of Dermatology, University of Wisconsin School of Medicine and Public Health, Madison
  • 8Department of Dermatology, The George Washington University School of Medicine and Health Sciences, Washington, DC
  • 9Department of Dermatology, Columbia University Irving Medical School, New York, New York
  • 10Department of Dermatology, University of California, San Francisco
  • 11Department of Dermatology, Duke University Medical Center, Durham, North Carolina
  • 12Division of Dermatology, CHU de Quebec, Laval University, Quebec City, Quebec, Canada
  • 13Department of Dermatology, Cleveland Clinic, Cleveland, Ohio
  • 14Department of Dermatology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
  • 15Department of Dermatology, Keck School of Medicine, Los Angeles, California
  • 16Department of Dermatology, University of Colorado, Boulder
JAMA Dermatol. Published online November 3, 2021. doi:10.1001/jamadermatol.2021.4314
Key Points

Question  Do some patients with dermatitis have clinically relevant patch test reactions to supplemental allergens/materials not detected by a screening series of 65 to 70 allergens?

Findings  In this cross-sectional study including 43 417 patients with dermatitis, 22% had a currently relevant reaction to 1 or more supplemental allergens or substances. Of these patients, 26% had no currently relevant reactions to 65 to 70 screening allergens.

Meaning  These findings suggest that comprehensive patch testing with more than 70 allergens, including supplemental series and personal and work materials, is necessary for proper identification of allergens and successful management of allergic contact dermatitis.


Importance  Patch test screening series for patients with dermatitis are limited and may miss clinically relevant contact allergens.

Objective  To characterize individuals with dermatitis who showed clinically relevant patch test findings to supplemental (nonscreening) allergens or substances.

Design, Setting, and Participants  A 17-year, retrospective cross-sectional analysis (January 1, 2001, to December 31, 2018) of North American Contact Dermatitis Group (NACDG) data from multiple centers in North America was conducted. A total of 43 417 patients with dermatitis underwent patch testing to the NACDG screening series in a standardized manner with 65 to 70 allergens and supplemental allergens as clinically indicated. Patients with 1 or more clinically relevant reactions to a supplemental (nonscreening) allergen/substance were analyzed between November 18, 2020, and March 12, 2021.

Main Outcomes and Measures  The main outcomes were to assess the number of patients with clinically relevant reactions to supplemental (nonscreening) allergens and compare characteristics (including demographic characteristics and occupations) between patients with a clinically relevant patch test reaction to 1 or more supplemental allergens or substances (supplement-positive) and those without a reaction (supplement-negative) using odds ratios (ORs) and 95% CIs. Secondary outcomes included sources of allergic contact dermatitis and, for occupationally related cases, specific occupations and industries.

Results  Of 43 417 patients included in the study who underwent patch testing to the NACDG screening series (65-70 allergens), 9507 individuals (21.9%) had currently relevant reactions to 1 or more supplemental allergens or substances. Of these, 6608 were women (69.5%) and the mean (SD) age was 47.2 (0.54) years. Compared with patients who had supplement-negative results, patients with supplement-positive findings were significantly less likely to be male (OR, 0.90; 95% CI, 0.85-0.94; P < .001) and/or have atopic dermatitis (OR, 0.89; 95% CI, 0.84-0.93; P < .001). Common primary sites of dermatitis in 9499 patients with supplement-positive findings included the face (2856 [30.1%]), hands (2029 [21.4%]), and scattered/generalized distribution (1645 [17.3%]). Frequent sources of supplemental allergens in 9235 patients included personal care products (4746 [51.4%]) and clothing/wearing apparel (1674 [18.1%]). Of 9362 patients with available data, supplemental allergens/substances were occupationally related in 1580 (16.9%); of those with identified occupations, 25.1% (384 of 1529) were precision production, craft, or repair workers. Of 9507 patients with supplement-positive findings, 2447 (25.7%) had no currently relevant reactions to NACDG screening allergens.

Conclusions and Relevance  This cross-sectional study found that 21.9% of patients who underwent patch testing to an allergen screening series of 65 to 70 allergens had at least 1 relevant reaction to supplemental allergens/substances. Of these, one-quarter reacted only to a supplemental allergen/substance. Screening series include common, important allergens, but these findings suggest that the addition of specialty allergens and personal or work products is critical for the successful diagnosis and management of allergic contact dermatitis.

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