To Örebro University

BACKGROUND: Allergic contact dermatitis has considerable public health impact and causative haptens vary over time.

OBJECTIVES: To report contact allergy prevalence to allergens in the Swedish baseline series 2010-2017, as registered in the Swedish Patch Test Register.

METHODS: Results and demographic information for patients tested with the Swedish baseline series in 2010-2017 were analyzed.

RESULTS: Data for 21 663 individuals (females 69%) were included. Females had significantly more positive patch tests (54% vs 40%). The reaction prevalence rates were highest for nickel sulfate (20.7%), fragrance mix I (7.1%), Myroxylon pereirae (6.9%), potassium dichromate (6.9%), cobalt chloride (6.8%), methylchloroisothiazolinone/methylisothiazolinone (6.4%), methylisothiazolinone (3.7%), colophonium (3.5%), fragrance mix II (3.2%) and formaldehyde (3.2%). Myroxylon pereirae reaction prevalence increased from 5% in 2010 to 9% in 2017 and that for methyldibromo glutaronitrile from 3.1% to 4.6%. Methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone reactions decreased in prevalence after 2014. Nickel reaction prevalence decreased among females aged 10-19 years.

CONCLUSIONS: Nickel remains the most common sensitizing agent, with reaction prevalence decreasing among females younger than 20 years. The changes in methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone reaction prevalence mirrored those in Europe. The register can reveal changes in contact allergy prevalence over time among patients patch tested in Sweden. This article is protected by copyright. All rights reserved.