Episode 43 - European Photopatch Test Study (POST)

In this episode of BJD Talks, Sam and Meera discuss the article ‘Prospective multicentre photopatch test study of photoallergy to sunscreens and nonsteroidal anti-inflammatory drugs in Europe’ by Ralph et al. The full article can be accessed at https://doi.org/10.1093/bjd/ljag085 

*This podcast was generated by an AI tool created by 67Bricks for the British Association of Dermatologists*

Transcript

SPEAKER_00 0:00

Welcome to BJD Talks, the official podcast of the BJD. I'm Sam.

SPEAKER_01 0:04

And I'm Mira. In this episode, we will be discussing the article by Nicola Ralph et al., Prospective Multi-Centre Photo Patch Test Study of Photoallergy to Sunscreens and Non-steroidal anti-inflammatory drugs in Europe from March 2026 and included in the July 2026 issue.

SPEAKER_00 0:24

This article explores photo patch testing, the gold standard for diagnosing photoallergic contact dermatitis. It's technical, yes, but has substantial clinical relevance for dermatologists.

SPEAKER_01 0:36

It does. What stands out is the scale, conducted across 10 centres in seven European countries with 132 participants. They focused on sunscreens, NSADS, and other potential photoallergens. Such cross-border collaboration provides both robust data and valuable diversity of insight.

SPEAKER_00 0:57

Indeed. And the methodology adds weight to the findings. For example, using 24-hour versus 48-hour occlusion periods before ultraviolet irradiation revealed a 53% missrate for sunscreen-related photoallergies with 24-hour occlusions. That difference alone could significantly alter clinical practice.

SPEAKER_01 1:19

Yes, and what's notable is the prevalence of photoallergic reactions. 10% for sunscreens and 9% for NSADS. Chemicals like ketoprofen, avobenzone, and oxybenzone were top culprits, highlighting ongoing challenges in identifying stable photoallergens over time.

SPEAKER_00 1:38

The suggestion to adopt a 48-hour occlusion period is certainly pivotal, though practicality in busy dermatology clinics might be an issue. An extra day seems minimal during research, but could complicate scheduling in real-world settings.

SPEAKER_01 1:54

True, though, the study is pragmatic. It accommodated patients with photodermatoses, like polymorphic light eruption, by using reduced UVA doses. This adaptability is important for patients with heightened photosensitivity.

SPEAKER_00 2:08

And they emphasized vigilance. Although the photoallergens identified remain stable, new products frequently enter the market. It's a clear reminder that periodic updates to photopatch test series are essential.

SPEAKER_01 2:22

I also found the idea of late readings, day 7 for example, interesting. Though rarely used in this study, the findings in at least one case emerged only during late readings. It underlines the need for nuance and the benefits of standardization in photopatch testing.

SPEAKER_00 2:39

Yes, and the researchers were upfront about limitations. Recruitment challenges due to the pandemic and the lack of a formal power calculation due to the pragmatic nature of the study were acknowledged. But the high-quality design and consistent methodologies ensure the findings remain robust.

SPEAKER_01 2:56

To summarise, photo patch testing is indispensable, especially in case of dermatitis on photo exposed sites or suspected reactions to sunscreens and ensides. Using a 48-hour occlusion period could greatly improve accuracy, and we must remain alert to the ever-changing landscape of chemical exposures.

SPEAKER_00 3:16

Precisely. This study presents opportunities to refine current practices and reinforces the importance of staying updated. Photopatch testing, while specialized, impacts allergy identification, patient quality of life, and public health standards as sunscreen formulations evolve.

SPEAKER_01 3:34

Well put, Sam. Thank you to our listeners for tuning in to BJD Talks. Until next time.