Allergic contact dermatitis to detergents: a multicenter study to assess prevalence.

BACKGROUND: Allergic contact dermatitis (ACD) to optical brighteners and enzymes in laundry detergents was the focus of numerous reports in the early 1970s. Subsequently, there has been little published on the incidence of allergic reactions to chemicals in laundry detergents. Nonetheless, consumers and physicians continue to ascribe allergic contact reactions to laundry detergents. OBJECTIVE: This article reports the findings of a multicenter study on the prevalence of patch test reactions to a liquid and a granular laundry detergent provided by Procter & Gamble Company (Cincinnati, Ohio). METHODS: Patients referred to members of the North American Contact Dermatitis Group for evaluation of potential ACD were invited to participate in the study, which involved the placement of 2 patch tests (a 0.1% aqueous dilution of a granular laundry detergent and a 0.1% aqueous dilution of a liquid laundry detergent). Whether the patients had atopic dermatitis and whether they or their physicians felt that their dermatitis might be related to laundry detergents were noted. Reactions to the laundry detergents were correlated with allergic reactions to the following screening chemicals: fragrances, nickel, and potassium dichromate. Patients who experienced a reaction to at least one of the laundry detergents could enter phase II of the study, which involved testing to varying dilutions of the laundry detergents, to 0.1% sodium lauryl sulfate (as an irritant control), and to laundered patches of cotton. Patients positive in phase II could enter phase III, which involved wearing a garment laundered with the detergent. Phases II and III were double blinded. RESULTS: Of the 3120 patients seen by members of the North American Contact Dermatitis Group during the 2 years of this study, 738 patients volunteered to enroll. Enrollment was not statistically randomized. Of these 738, 5 (0.7%) had positive patch test reactions to granular laundry detergent (0.1%, aqueous); 3 of these 5 also had positive reactions to the liquid laundry detergent (0.1%, aqueous). In 4 of the 5 patients, the reaction to detergent was thought to have present relevance to their dermatitis; in 1 of the 5, the reaction was deemed to have past relevance. One of these 5 patients had allergy to fragrances. None of the patients was positive to nickel or chromate. Two of the 5 entered phases II and III. Of these 2 patients, 1 had essentially negative repeat dilutional patch testing and "use testing" suggesting that the earlier reaction patterns may have been irritant. The remaining patient had positive dilutional reactions to both the liquid and granular laundry detergent; however, she also had a positive reaction to sodium lauryl sulfate and to a swatch from a T-shirt laundered without detergent. Upon "use testing" in phase III, this latter patient experienced diffuse dermatitis under both the half of the T-shirt laundered with detergent and that laundered without detergent. CONCLUSION: Laundry detergents appear to be a rare cause of ACD. Among 738 patients with dermatitis, 5 (0.7%) reacted to a 0.1% aqueous dilution of a laundry detergent. Only 2 of these 5 patients could be evaluated in greater detail to differentiate allergic from irritant patch test reactions to detergents. Upon further testing in 2 patients, the reaction in 1 of 2 could not be reduplicated and the reaction in the other was invoked both by the detergents and the controls. Thus, whether our study patients were truly allergic and, if so, what the allergenic material(s) in detergents might be, remains unknown. Therefore the reported incidence rate for detergent-induced allergy of 0.7% in dermatitic patients may be too high, possibly because of false-positive irritant reactions.

The effect of race and ethnicity on patch test results.

BACKGROUND: Allergic contact dermatitis is a condition that may be affected by differences in genetic and environmental factors. Race and ethnicity are possible examples of the former. OBJECTIVE: The objective of this study was to examine the differences in patch test results between white and black individuals tested by the members of the North American Contact Dermatitis Group from July 1, 1992, to June 30, 1998. METHODS: Patients evaluated in our patch test clinics were exposed to a standardized patch testing technique involving a standard series of 41 allergens in total. The standard series we used varied over the 6 years of the study in 2-year cycles. The series was the same at all centers during each of these 2-year cycles: 1992-94, 1994-96, and 1996-98. Over a 6-year period, our group tested 9624 patients. Of those individuals, 8610 (89.5%) were white and 1014 (10.5%) were black. RESULTS: Allergic contact dermatitis and irritant contact dermatitis were the final diagnoses assigned by the investigators to individuals of the 2 races: 49% and 16%, respectively, for the white patients and 46% and 15%, respectively, for the black patients. In at least one of the three 2-year periods, testing in white patients revealed higher rates of sensitization to formaldehyde, glutaraldehyde, and a number of the formaldehyde-releasing preservatives, as well as lanolin, epoxy resin, thioureas, and balsam of Peru. Black patients exhibited higher rates of sensitization to para-phenylenediamine, cobalt chloride, thioureas, and p-tert-butylphenol formaldehyde resin in at least one of the 2-year periods. CONCLUSION: In this test population, we found no differences in the overall response rate to allergens. There were some differences between white and black patients in their response to specific allergens. These differences, although possibly related to genetic factors based on race, are more likely related to differences in allergen exposure determined by ethnicity.