The British standard series of contact dermatitis allergens: validation in clinical practice and value for clinical governance

BACKGROUND: All centres use an empirically determined set of 'standard' test allergens for patch testing that contain the commoner environmental sensitizers. Objectives To assess the validity of the British standard series of 12 allergens used in addition to the 23 already in the European standard series. PATIENTS AND METHODS: Results for 3062 consecutive patients patch tested in seven centres across the United Kingdom during the year 2000 were analysed. RESULTS: The additional allergens from the British series and positive rates were: methyl dibromoglutaronitrile 2.4%, carba mix 1.6%, tixocortol pivalate 1.5%, ethylenediamine 1.3%, cetearyl alcohol 0.8%, 2-bromo-2-nitropane-1,3-diol 0.8%, diazolidinyl urea 0.7%, chlorocresol 0.6%, budesonide 0.6%, fusidic acid 0.5%, imidazolidinyl urea 0.5%, and chloroxylenol 0.4%. The allergens with the lowest positive rate in the European standard series were primin at 0.6% and isopropyl-phenyl-para-phenylenediamine at 0.4%. CONCLUSIONS: The 12 allergens in the British series should continue being tested as a standard addition to the European series within the U.K. The collection of data in this manner to allow comparisons between centres shows differences that reflect selection criteria and interpretation of results, and offers a useful tool for audit and clinical governance. Testing fewer than 1 : 2150 population may indicate underprovision of service. Similarly, rates of sensitization for nickel contact allergy above 26% and for fragrance mix above 16% (the upper 95% confidence intervals) should stimulate inquiry into the reasons behind this.