Positive Patch Test Reaction Rates Similar for Elderly, Adults

Particularly sensitive to preservatives, fragrance and flavoring markers, and topical antimicrobials

FRIDAY, Jan. 20 (HealthDay News) -- Approximately two-thirds of older individuals have at least one positive patch test reaction to contact allergens, similar to the rates for adults and significantly increased compared with the rates for children, according to a study published in the February issue of the Journal of the American Academy of Dermatology.

Erin M. Warshaw, M.D., from the Minneapolis Veterans Affairs Medical Center, and colleagues retrospectively analyzed data from 31,942 patients in the North American Contact Dermatitis Group (collected from 1994 to 2008). Groups referred for patch testing were defined as older individuals (5,306 aged ≥65 years), adults (25,028 aged ≥19 to ≤64 years), and children (1,608 aged ≤18 years).

The researchers found that the overall frequency of at least one allergic reaction in older individuals was 67.3 percent, compared with 66.9 percent for adults (P = 0.5938) and 47 percent for children (P = 0.0011). Compared with adults or children, reaction rates were significantly higher in older individuals for Myroxylon pereirae, fragrance mix I, quaternium-15, formaldehyde, imidazolidinyl urea, diazolidinyl urea, neomycin, bacitracin, methyldibromo glutaronitrile, methyldibromo glutaronitrile/phenoxyethanol, ethyleneurea melamine formaldehyde mix, and carba mix. Significantly lower patch test reaction rates were seen for older individuals for nickel, thimerosal, and cobalt.

"Older individuals were more likely to have at least one positive patch test reaction as compared with children, but had similar rates to adults," the authors write.

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