Lim SYD, Goon ATJ, Leow YH, Chong TYR, Tan EST, Cheng WNS. Photopatch testing in Singapore: A 10-year retrospective study.
PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE 2023;
39:642-647. [PMID:
37749909 DOI:
10.1111/phpp.12912]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 08/21/2023] [Accepted: 08/28/2023] [Indexed: 09/27/2023]
Abstract
BACKGROUND
Photopatch testing represents the gold standard for the diagnosis of photoallergic contact dermatitis (PACD). We aimed to identify common photoallergens in our tertiary dermatological referral centre from 2012 to 2021, to compare this to the preceding period studied, and data from other communities.
METHODS
We conducted a retrospective review of all 90 patients who underwent photopatch testing at the National Skin Centre, Singapore, between 2012 and 2021.
RESULTS
Of 90 patients, 19 (21.1%) were male, and the mean age was 41.6 years. Eighty-four (93.3%) underwent testing to our standard sunscreen series, 10 (11.1%) to our extended series, and 73 (81.1%) to their own items. Seventeen (18.9%) were diagnosed with PACD (i.e., photocontact allergy with present or past relevance), 12 (13.3%) with ACD, and 4 (4.4%) with photoaugmented ACD. Relevant reactions were commonest to oxybenzone (8, 9.5%) and mexenone (3, 3.6%). Eleven (15.1%) had PACD to their own items, with 3 of 4 (75%) tested to ketoprofen diagnosed with PACD and the remaining 1 (25%) with photoaugmented ACD. Age, race, sex, atopy, and site of involvement were not associated with photocontact allergy. Compared to the preceding time period, the overall frequency of photocontact allergy and PACD decreased, but rates of photoallergic reactions to individual photoallergens were not significantly different.
CONCLUSION
Organic ultraviolet absorbers such as oxybenzone and mexenone remained the most relevant photoallergens. Personal item testing was valuable, and testing to ketoprofen should be considered.
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