Porphyria patients face a difficult dillema every day: how best to protect themselves from harmful light (photo-protection). Medicines, sun-avoidance, and protective clothing all play a part in a patient’s photo-protection strategy, but so too do sunscreens. Therein lies another struggle, which is the choice of sunscreen. Available in hundreds of brands, at a variety of prices, and with myriad claims on photo-protection efficacy across the Ultraviolet (UVB and UVA) and visible bands of the spectrum, the decision-making can prove difficult even for non-photosensitive individuals. Moreover, porphyria patients are sensitive across the PPIX spectrum, which has multiple peaks across the breadth of the UV and visible spectrum. Therefore, whilst a UV-sunscreen will protect from some of these bands, it will be ineffective against others. Similarly, whilst visible sunscreens provide broad protection in both the UV and visible bands, they come with their own range of drawbacks. Compared to their UV counterparts, visible sunscreens are not so widely known, are often not available on the supermarket shelves, and, importantly, are pigmented. This means that a patient must match the pigment of their skin to that of the sunscreen, and given the limited choices available, this can prove difficult from person to person, and even across areas of the body. Furthermore, sunscreen is no guarantee of protection, but rather increases the time allowed until a photosensitive reaction occurs. This will also vary depending on the manner in which the individual has applied the sunscreen; how light or how heavy, in patches, over make up, in wet or dry conditions.

Our research brings these issues into focus in a number of areas. Firstly, we have been routinely testing sunscreens of all types using our spectrophotometer in order to analyse their protective qualities, some of which has been previously published (Eadie et al., 2023, doi.org/10.1093/bjd/ljac112). We have found that protection varies from product to product, which is a particular issue for porphyria patients who may have to test multiple products before settling on the best protection for them. Secondly, we have been polling our photosensitive patients to understand more about the role sunscreens play in their photo-protection strategies. Through this type of patient-engagement, we have learned about the value patients place on factors such as cost, availability and application against other photo-protection methods such as sun-avoidance and protective clothing. We are extending this to porphyria patients in conjunction with the British Porphyria Association (BPA) and will present the results of this survey. Thirdly, we have begun building a public-access database of sunscreens with the intention of allowing patients to discover the protective qualities of these products for themselves, whilst comparing them side-by-side. We plan to engage with the BPA to facilitate patient-friendly guidance on photo-protection.