What is in? What is out? Updating the British Society for Cutaneous Allergy facial series*.

Summary: Background: Allergic contact dermatitis (ACD) to cosmetics is widely reported. To ensure we are accurately diagnosing ACD, patch test series should be continually reviewed to identify relevant and emerging allergens and highlight those that are outdated. The current British Society for Cutaneous Allergy (BSCA) facial series recommends 26 allergens and was last modified in 2012. Objectives: To review and update the BSCA facial series. Methods: We retrospectively reviewed the results from 12 UK and Ireland patch test centres' facial series from January 2016 to December 2017. We recorded the number of allergens tested in each centre and the detection rate for each allergen. Using a 0·3% positive rate as the inclusion threshold, we established which allergens in the BSCA facial series had positive patch test rates < 0·3% and > 0·3%. Allergens not in the BSCA facial series that had a positive patch test rate > 0·3% were identified. Results: Overall, 4224 patients were patch tested to the facial series. The number of allergens included in individual centres' facial series ranged from 24 to 66, with a total of 103 allergens tested across all centres. Twelve of the 26 allergens in the BSCA facial series had a positive patch test rate < 0·3% and 14 had a rate > 0·3%. Twenty‐five allergens not recommended in the BSCA facial series had a positive patch test rate > 0·3%. Conclusions: This audit has highlighted the significant variation in practice that exists among patch test centres, despite a recommended facial series. The BSCA facial series has been updated and now contains 24 allergens. Fifteen allergens remain, 11 allergens have been dropped and nine new allergens have been added. What is already known about this topic? Facial dermatitis is one of the dominant presenting complaints of allergic contact dermatitis to cosmetics.To ensure we are accurately diagnosing contact allergy, it is important that we patch test with relevant allergens.Reviewing current literature and auditing patch test practice is a vital requirement to ensure we identify relevant and emerging allergens and highlight those that are outdated. What does this study add? Despite recommended patch test series, there is significant variation in practice among different patch test centres.In response to this multicentre audit, the British Society for Cutaneous Allergy facial series has been updated and now contains 24 allergens: 15 allergens remain, 11 allergens have been dropped and nine new allergens have been added. Linked Comment:Boonchai. Br J Dermatol 2021; 184:13. Plain language summary available online [ABSTRACT FROM AUTHOR]