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Erythropoietic protoporphyria (EPP) is characterised by accumulation of protoporphyrin IX (PpIX) in erythrocytes. Upon illumination PpIX is released to the skin. Activation of the photoactive substance PpIX causes painful skin symptoms. This study aimed to objectively quantify individual light exposure of EPP patients in their everyday lives through spring and summer. We further aimed to establish the associations between daily symptoms and light exposure dose to photoprimed and non-photoprimed skin, use of gloves, and erythrocyte PpIX concentration. 14 Danish EPP patients participated from April through June, the period when symptoms are most frequent. Light exposure was measured using personal electronic dosimeters with sensor sensitivity comparable to the absorption spectrum of PpIX, measuring the biological effect of the light in this disease. Concurrently participants reported symptoms and use of protective gloves in a diary. Patients had a blood sample analysed for erythrocyte PpIX. The median patient was exposed to an average daily PpIX-weighted light dose of 3.8 J/cm 2 corresponding to approximately 15 min in the midday sun during summer in Denmark. The median patient reported symptoms on 29% and wore gloves on 11% of study days. There was a significant positive correlation between erythrocyte PpIX concentration and percentage of days wearing gloves (r = 0.65, p = 0.011), and a significant negative correlation between erythrocyte PpIX concentration and mean daily light dose on days not wearing gloves (r = -0.53, p = 0.049). Photosensitivity was strongly dependent on photopriming., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The rule of thumb "Fill up a handful of sunscreen and spread it all over your body" has been used in several sun safety campaigns. The intention was to increase the applied sunscreen to obtain a quantity of 2 mg/cm 2 to all accessible skin. The present study is the first to investigate how this advice works in practice, evaluated by quantity of sunscreen applied and amount of covered skin., Methods: Seventeen volunteers wearing swimwear were asked to "Fill up a handful and spread it all over your body." Before and after sunscreen application, the volunteers were photographed in black light. As sunscreen absorbs black light, the darkness of the skin increases with increasing amounts of applied sunscreen, making it possible to identify skin left without coverage. The sunscreen container was weighed before and after to quantify the amount of sunscreen applied., Results: A median of 21% of the accessible skin was left completely without coverage. The 79% covered area was covered with a median of 1.12 mg/cm 2 , not the expected 2 mg/cm 2 ., Conclusion: In practice, the advice "Fill up a handful of sunscreen and spread it all over your body" led to a better but still modest protection, compared to the intended effect.

Sunscreen users are often inadequately protected and become sunburned. This study aimed to investigate how much two consecutive sunscreen applications increased the quantity of sunscreen applied and decreased the skin area left without sunscreen (missed area) compared to a single application. Thirty-one healthy volunteers wearing swimwear were included and applied sunscreen two consecutive times in a laboratory environment. Participants had pictures taken in black light before and after each application. As sunscreens absorb black light, the darkness of the skin increased with increasing amounts of sunscreen applied. We conducted a standard curve establishing a link between change in picture darkness and quantity of sunscreen. The quantity of sunscreen at selected skin sites as well as the percentage of missed area was determined after each application. Participants had missed a median of 20% of their available body surface after a single application. After double application they had missed 9%. The decrease in missed areas was significant for the whole body surface and for each of the body regions separately. The median participant had applied between 13% and 100% more sunscreen at the selected skin sites after double application than after single application. We recommend double application, especially before intense sun exposure.

Interferon‐beta has been suggested as a trigger of psoriasis, yet a systematic investigation is lacking. This study aimed to assess the risk of developing psoriasis following interferon‐beta treatment, utilizing a pharmaco‐epidemiological approach to investigate the role of interferon‐beta in psoriasis pathogenesis. We included all treatment‐naïve patients with multiple sclerosis (MS) in Denmark who initiated interferon‐beta treatment for MS from January 1996 to June 2023. These patients were compared to a control cohort of patients with MS treated with other disease‐modifying drugs. We compared the incidence rates of psoriasis before and during the treatment. Data for this study were extracted from the Danish MS Registry and integrated with information from other national Danish health registries. Among 7174 patients treated with interferon‐beta, the incidence rate of psoriasis post‐treatment initiation was slightly higher (2.01 per 1000 person‐years) compared to the rate prior to treatment (1.67 per 1000 person‐years). This increase did not achieve statistical significance (P = 0.53), with an incidence rate ratio (IRR) of 1.20 (95% confidence interval [CI] 0.68–2.13). The control cohort showed an increase in psoriasis incidence post‐treatment initiation (3.12 per 1000 person‐years) compared to prior (1.11 per 1000 person‐years), with an IRR of 2.80 (95% CI 1.36–4.77, P = 0.0038). This registry‐based self‐controlled study does not support the theory that interferon‐beta acts as a trigger for psoriasis development. [ABSTRACT FROM AUTHOR]

• Erythropoietic protoporphyria (EPP) is characterized by painful photosensitivity. • Dihydroxyacetone (DHA) darkens the skin providing theoretical light protection. • We present cases with EPP suggesting decreased photosensitivity by DHA application. • A protocol for a randomized trial to include patients with EPP is enclosed. • The aim is to investigate the effect of DHA under controlled clinical conditions. Patients with erythropoietic protoporphyria (EPP) are hypersensitive to long wave ultraviolet (UVA) radiation and visible light and they experience severe skin pain by light exposure. The patients have very limited treatment options. Sunless skin tanning with dihydroxyacetone (DHA) is now being investigated as a possible treatment modality of skin photosensitivity in EPP. We simulated the theoretical light protection factor provided by DHA application. In addition, we present 19 cases with EPP who were treated at our department with DHA weekly during spring and summer from 2018 to 2021 inclusive. The protection factor against UVA and visible light was estimated to approximately two. Out of the 19 patients with EPP who were treated with DHA in 2018, 11 patients experienced a sustained good effect and continued to use the treatment on a weekly basis in the spring and summer of 2019, 2020, and 2021. Both the theoretical estimates and the uncontrolled study suggest that sunless tanning with DHA reduces photosensitivity in patients with EPP. Our hypothesis is that skin treated with DHA can tolerate twice the daylight dose compared to untreated skin before onset of skin symptoms. To validate this conclusion, we plan a randomized clinical trial to determine the effect of DHA application to reduce photosensitivity in patients with EPP under controlled clinical conditions. The study protocol for this trial is presented in the paper. [Display omitted] [ABSTRACT FROM AUTHOR]