Patch testing with the irritant sodium lauryl sulfate (SLS) is useful in interpreting weak reactions to contact allergens as allergic or irritant

• Published in: Contact dermatitis Vol. 48; no. 2; pp. 99 - 107
• Main Authors: Geier, J., Uter, W., Pirker, C., Frosch, P. J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Munksgaard International Publishers 01.02.2003; Blackwell
• Subjects: Allergens; Allergic diseases; Biological and medical sciences; Cohort Studies; Confidence Intervals; contact allergy; Dermatitis, Allergic Contact - diagnosis; Dermatitis, Allergic Contact - epidemiology; erythematous patch test reactions; false-positive patch test reactions; Female; Germany - epidemiology; Humans; Immunopathology; Incidence; irritant; Irritants - adverse effects; Irritants - pharmacology; Logistic Models; Male; Mass Screening - methods; Medical sciences; patch testing; Patch Tests; Probability; Retrospective Studies; Risk Assessment; Sensitivity and Specificity; Skin allergic diseases. Stinging insect allergies; Sodium Dodecyl Sulfate - adverse effects; Sodium Dodecyl Sulfate - pharmacology; sodium lauryl sulfate; threshold; Germany; Human; Immunopathology; Allergy; sodium lauryl sulfate; Methodology; threshold; erythematous patch test reactions; patch testing; Differential diagnostic; contact allergy; false-positive patch test reactions; irritant; Patch; Allergen; Irritation; Skin test
• ISSN: 0105-1873; 1600-0536
• DOI: 10.1034/j.1600-0536.2003.480209.x

Several contact allergens are tested at concentrations which might cause irritant reactions. In this study we investigated whether the reactivity to a standard irritant is useful in identifying subjects with hyperreactive skin yielding a higher rate of doubtful or irritant reactions. Sodium lauryl sulfate (SLS) 0.5% (aqua) was tested in addition to the standard series routinely for 5 years in the Department of Dermatology, Dortmund. For data analysis, we compared reactions at D3 to the standard series, the vehicle/emulsifier and preservative series and benzoyl peroxide to the reactions obtained with SLS. Proportions were standardized for age and sex. The association between reactivity to a certain allergen and SLS reactivity as a dichotomous outcome, controlled for age and sex as potential confounders, was assessed with logistic regression analysis. Results showed that of the 1600 tested patients, 668 (41.8%) had an irritant reaction to SLS which exceeded 2 + in only 41 patients. Seasonal variation was statistically significant, showing reduced SLS reactivity in summer vs. winter. Patients with irritant reactions to SLS showed significantly more erythematous reactions to the following 10 allergens of the standard series: fragrance mix, cobalt chloride, balsam of Peru (Myroxylon pereirae), lanolin alcohol, 4‐phenylenediamine base (PPD), propolis, formaldehyde, N‐isopropyl‐N′‐phenyl‐p‐phenylenediamine (IPPD), benzocaine, and 4‐tert‐butylphenol‐formaldehyde resin. No significant differences regarding strong positive allergic reactions were observed. Concerning other allergens, significantly more erythematous reactions were observed in SLS‐reactive patients to benzoyl peroxide, octyl gallate, cocamidopropyl betaine, Amerchol L‐101, tert‐butylhydroquinone, and triethanolamine. In the SLS‐reactive group of patients, the reaction index was negative for 10 allergens of the standard series compared to only 5 in the SLS non‐responder group. For the first time, this study, based on a large data pool, revealed a significant association between reactivity to the irritant SLS and erythematous reactions to certain allergens. With SLS as a marker for hyperreactive skin at hand, some of these reactions can now be classified as irritant more confidently, particularly if there is no history of exposure to the allergen.