TY - JOUR

T1 - Phototesting in erythropoietic protoporphyria trials

T2 - A systematic review

AU - Heerfordt, Ida M.

AU - Philipsen, Peter A.

AU - Lerche, Catharina M.

AU - Wulf, Hans Christian

N1 - Funding Information: The work was supported by a grant from the Alfred Benzon Foundation, Denmark. Model photograph in the graphical table of contents was provided by ColourBox.com . Publisher Copyright: © 2023 The Authors. Experimental Dermatology published by John Wiley & Sons Ltd.

PY - 2023

Y1 - 2023

N2 - Severe skin pain when exposed to long wave ultraviolet radiation or visible light is the main symptom of erythropoietic protoporphyria (EPP). Treatment options for EPP are inadequate and new treatments are needed but hampered by the lack of valid efficacy outcomes. Phototesting with well-defined illumination of the skin can be performed reliably. We aimed to provide an overview of phototest procedures used to evaluate EPP treatments. Systematic searches of Embase, MEDLINE and the Cochrane Library were performed. Searches identified 11 studies using photosensitivity as efficacy outcome. The studies used eight different phototest protocols. Illuminations were performed with a filtered high-pressure mercury arc, or a xenon arc lamp equipped with monochromator or filters. Some used broadband, others narrowband illumination. In all protocols phototests were performed on the hands or the back. Endpoints were minimal dose required to induce either first symptom of discomfort, erythema, urticaria or intolerable pain. Other endpoints were change in erythema intensity or diameter of any type of flare after exposure compared to before. In conclusion, protocols displayed extensive variability in illumination set-up and evaluation of phototest reactions. Implementation of a standardized phototest method will allow more consistent and reliable outcome evaluation in future therapeutic research of protoporphyric photosensitivity.

AB - Severe skin pain when exposed to long wave ultraviolet radiation or visible light is the main symptom of erythropoietic protoporphyria (EPP). Treatment options for EPP are inadequate and new treatments are needed but hampered by the lack of valid efficacy outcomes. Phototesting with well-defined illumination of the skin can be performed reliably. We aimed to provide an overview of phototest procedures used to evaluate EPP treatments. Systematic searches of Embase, MEDLINE and the Cochrane Library were performed. Searches identified 11 studies using photosensitivity as efficacy outcome. The studies used eight different phototest protocols. Illuminations were performed with a filtered high-pressure mercury arc, or a xenon arc lamp equipped with monochromator or filters. Some used broadband, others narrowband illumination. In all protocols phototests were performed on the hands or the back. Endpoints were minimal dose required to induce either first symptom of discomfort, erythema, urticaria or intolerable pain. Other endpoints were change in erythema intensity or diameter of any type of flare after exposure compared to before. In conclusion, protocols displayed extensive variability in illumination set-up and evaluation of phototest reactions. Implementation of a standardized phototest method will allow more consistent and reliable outcome evaluation in future therapeutic research of protoporphyric photosensitivity.

KW - erythropoietic protoporphyria

KW - photodynamic reaction

KW - photosensitivity

KW - phototest

KW - protoporphyrin IX

KW - X-linked protoporphyria

U2 - 10.1111/exd.14809

DO - 10.1111/exd.14809

M3 - Review

C2 - 37052136

AN - SCOPUS:85152791888

VL - 32

SP - 1042

EP - 1047

JO - Experimental Dermatology

JF - Experimental Dermatology

SN - 0906-6705

IS - 7

ER -