Prospective multicentre photopatch test study of photoallergy to sunscreens and nonsteroidal anti-inflammatory drugs in Europe

TY - JOUR

T1 - Prospective multicentre photopatch test study of photoallergy to sunscreens and nonsteroidal anti-inflammatory drugs in Europe

AU - Ralph, Nicola

AU - Goossens, An

AU - Carrascosa, Jose M.

AU - Goncalo, Margarida

AU - Wulf, Hans Christian

AU - Calzavara-Pinton, Piergiacomo G.

AU - Rhodes, Lesley E.

AU - Wilkinson, Mark

AU - Bourke, John

AU - Eadie, Ewan

AU - Moore, Edward

AU - Christou, Evangelos

AU - Ibbotson, Sally H.

N1 - Copyright: © The Author(s) 2026. Published by Oxford University Press on behalf of British Association of Dermatologists. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

PY - 2026/7

Y1 - 2026/7

N2 - Background: While photopatch testing is recognized as the investigation of choice for photoallergic contact dermatitis, changes in potential photoallergen exposure and variables within the photopatch test technique have led to challenges in its usage within dermatology.Objectives: The main objectives of this study were to determine the nature and prevalence of topical photoallergens in Europe and to investigate the variable of photoallergen occlusion time before irradiation on photopatch testing outcomes.Methods: A prospective multicentre study of photopatch testing to sunscreens, nonsteroidal anti-inflammatory drugs (NSAIDs) and other agents was conducted in 10 centres across seven European countries. A within-participant comparison of a 24-h and 48-h occlusion period prior to irradiation was included in the study design, to investigate the effect of this variable on photopatch testing outcomes.Results: Of study participants, 28 photoallergic reactions were seen, with 10% (13 of 132) of participants reacting to sunscreen chemicals and 9% (9 of 101) to NSAIDs. The most prevalent photoallergens were ketoprofen (n = 6), promethazine (n = 4), butylmethoxydibenzoylmethane (avobenzone/parsol 1789) (n = 4), benzophenone-3 (oxybenzone) (n = 3) and etofenamate (n = 3). Contact allergies were less frequent (14 reactions). When a 24-h occlusion was used prior to irradiation, 53% of sunscreen photoallergic reactions and 36% of NSAID reactions were missed compared with the 48-h occlusion. Most participants had a history of photoexposed site dermatitis or sunscreen/NSAID reaction or had a photosensitivity disease, and 49% of participants had a history of dermatological conditions. All indications for photopatch testing were represented in those with positive photopatch tests, with no specific indicator of those most at risk.Conclusions: Photopatch testing remains an essential investigation for people with suspected photocontact allergies. Based on these study findings, the nature of topical photoallergens appears to be stable, but vigilance and ongoing review are required. To optimize the pick-up rate of photoallergy, we recommend a 48-h occlusion period prior to irradiation, if practicable.

AB - Background: While photopatch testing is recognized as the investigation of choice for photoallergic contact dermatitis, changes in potential photoallergen exposure and variables within the photopatch test technique have led to challenges in its usage within dermatology.Objectives: The main objectives of this study were to determine the nature and prevalence of topical photoallergens in Europe and to investigate the variable of photoallergen occlusion time before irradiation on photopatch testing outcomes.Methods: A prospective multicentre study of photopatch testing to sunscreens, nonsteroidal anti-inflammatory drugs (NSAIDs) and other agents was conducted in 10 centres across seven European countries. A within-participant comparison of a 24-h and 48-h occlusion period prior to irradiation was included in the study design, to investigate the effect of this variable on photopatch testing outcomes.Results: Of study participants, 28 photoallergic reactions were seen, with 10% (13 of 132) of participants reacting to sunscreen chemicals and 9% (9 of 101) to NSAIDs. The most prevalent photoallergens were ketoprofen (n = 6), promethazine (n = 4), butylmethoxydibenzoylmethane (avobenzone/parsol 1789) (n = 4), benzophenone-3 (oxybenzone) (n = 3) and etofenamate (n = 3). Contact allergies were less frequent (14 reactions). When a 24-h occlusion was used prior to irradiation, 53% of sunscreen photoallergic reactions and 36% of NSAID reactions were missed compared with the 48-h occlusion. Most participants had a history of photoexposed site dermatitis or sunscreen/NSAID reaction or had a photosensitivity disease, and 49% of participants had a history of dermatological conditions. All indications for photopatch testing were represented in those with positive photopatch tests, with no specific indicator of those most at risk.Conclusions: Photopatch testing remains an essential investigation for people with suspected photocontact allergies. Based on these study findings, the nature of topical photoallergens appears to be stable, but vigilance and ongoing review are required. To optimize the pick-up rate of photoallergy, we recommend a 48-h occlusion period prior to irradiation, if practicable.

U2 - 10.1093/bjd/ljag085

DO - 10.1093/bjd/ljag085

M3 - Article

C2 - 41903515

SN - 0007-0963

VL - 195

SP - 79

EP - 89

JO - British Journal of Dermatology

JF - British Journal of Dermatology

IS - 1

ER -