Background: Patch testing is an important diagnostic tool for determination of substances responsible for allergic contact dermatitis.
Objective: This study reports the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2009, to December 31, 2010.
Methods: At 12 centers in North America, patients were tested in a standardized manner with a screening series of 70 allergens. Data were manually verified and entered into a central database. Descriptive frequencies were calculated, and trends were analyzed using χ2 statistics.
Results: A total of 4308 patients were tested. Of these, 2614 (60.7%) had at least 1 positive reaction, and 2284 (46.3%) were ultimately determined to have a primary diagnosis of allergic contact dermatitis. Four hundred twenty-seven (9.9%) patients had occupationally related skin disease. There were 6855 positive allergic reactions. As compared with the previous reporting period (2007–2008), the positive reaction rates statistically decreased for 20 allergens (nickel, neomycin, Myroxylon pereirae, cobalt, formaldehyde, quaternium 15, methydibromoglutaronitrile/phenoxyethanol, methylchlorisothiazolinone/methylisothiazolinone, potassium dichromate, diazolidinyl urea, propolis, dimethylol dimethylhydantoin, 2-bromo-2-nitro-1,3-propanediol, methyl methacrylate, ethyl acrylate, glyceryl thioglycolate, dibucaine, amidoamine, clobetasol, and dimethyloldihydroxyethyleneurea; P < 0.05) and statistically increased for 4 allergens (fragrance mix II, iodopropynyl butylcarbamate, propylene glycol, and benzocaine; P < 0.05). Approximately one quarter of tested patients had at least 1 relevant allergic reaction to a non-NACDG allergen. Hypothetically, approximately one quarter of reactions detected by NACDG allergens would have been missed by TRUE TEST (SmartPractice Denmark, Hillerød, Denmark).
Conclusions: These results affirm the value of patch testing with many allergens.
From the Departments of Dermatology, Minneapolis VA Health Care System and University of Minnesota, Minneapolis, Minn; New York-Presbyterian Columbia University, New York, NY; Cleveland Clinic, Cleveland, OH; McGill University Health Centre, Montreal, Canada; University of Toronto, Toronto, Canada; Ohio State University, Columbus, OH; Associates in Dermatology, Fort Myers, Fla; Department of Dermatology, Group Health Associates, Cincinatti, OH; Dartmouth-Hitchcock Medical Center, Lebanon, NH; St. Luke’s Roosevelt Hospital Ctr, Columbia University, New York, NY; University of Louisville, Louisville, KY; Milton S. Hershey Medical Center, Hershey, Penn; University of Ottawa, Ottawa, Canada; Oregon Health Science Univ., Portland, OR; and University of California-San Francisco Dermatology, San Francisco, Calif.
Address correspondence to Erin M. Warshaw, MD, MS, Dept 111K 1 Veterans Dr, Minneapolis, MN 55417. E-mail: firstname.lastname@example.org.
Disclaimer: The views expressed in this article are those of the authors and do not necessarily represent the position or policy of the Department of Veterans Affairs or the United States government.
The authors have no funding or conflicts of interest to declare.