The results may have implications for individual diagnosis and prevention and when comparing test results from various centres.

SummaryBackground Acrylates ⁄methacrylates are volatile substances. There might be a gradual decrease in acrylate ⁄methacrylate allergen content over time in patch test preparations but this has not yet been documented. Objectives To determine the allergen content of acrylates ⁄methacrylates in patch test preparations over time under different storage conditions. Methods Five acrylate ⁄methacrylate allergens [2-hydroxyethyl methacrylate (2-HEMA), methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), triethylene glycol diacrylate (TREGDA) and 2-hydroxypropyl acrylate (2-HPA)] in syringes and IQÔ chambers (Chemotechnique Diagnostics, Vellinge, Sweden) were analysed using gel permeation chromatography and high-performance liquid chromatography to measure the allergen content over time in samples stored in the freezer, refrigerator and under room temperature. Results The concentration of allergens in syringes decreased with time. Those stored at room temperature had the fastest rate of decrease, followed by those in the refrigerator and freezer. In most cases, in syringes or IQÔ chambers under all storage conditions, the MMA decreased most rapidly, followed by 2-HPA, 2-HEMA, EGDMA and TREGDA. The allergens in the IQÔ chambers rapidly disappeared, with almost all samples reaching nondetectable levels by day 8. MMA was the first to reach a nondetectable level -at day 2. Conclusions Acrylate ⁄methacrylate allergens are lost rapidly from IQÔ chambers especially if stored at room temperature. Allergens in syringes remain above 80% of their initial concentrations for longer periods compared with IQÔ chambers. In syringes and IQÔ chambers there is a slower rate of decrease in concentration when the storage temperature is lower. Allergens should be stored refrigerated, replaced regularly, and freshly applied on to test patches on the day of use.

The majority of toothpastes on the Swedish market contain l-carvone, but the concentration hardly relates to the advertised flavour or labelled ingredients. It is hitherto unknown whether the found concentrations are sufficient for induction of contact allergy in individuals with healthy oral mucosa or in those with oral lichenoid lesions or other mucosal disease.