Experimental and approved treatments for skin photosensitivity in individuals with erythropoietic protoporphyria or X-linked protoporphyria: A systematic review.

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are characterized by skin photosensitivity caused by accumulation of protoporphyrin IX. We aimed to review the clinical evidence of efficacy and safety of skin photosensitivity treatments in individuals with EPP or XLP. We systematically searched MEDLINE, Embase, the Cochrane Library, and ClinicalTrials.gov. A total of 40 studies with data on 18 treatment modalities were included. Comprehensive treatment safety data were obtained from the European Medicines Agency and the United States Food and Drug Administration. The studies used different outcome measures to evaluate the sensitivity without a generally accepted method to assess treatment effect on skin photosensitivity. Of the included studies, 13 were controlled trials. Gathered, the trials showed moderate positive effect of inorganic sunscreen application and subcutaneous implant of afamelanotide and no effect of organic sunscreen application, or oral treatment with beta-carotene, cysteine, N-acetylcysteine, vitamin C, or warfarin. Studies without control groups suggested treatment effect of foundation cream, dihydroxyacetone/lawsone cream, narrow-band ultraviolet B phototherapy, erythrocyte transfusion, extracorporeal erythrocyte photodynamic therapy, or oral treatment with zinc sulphate, terfenadine, cimetidine, or canthaxanthin, but the real effect is uncertain. Assessment of treatment effect on photosensitivity in patients with EPP or XLP carries a high risk of bias since experienced photosensitivity varies with both weather conditions, exposure pattern, and pigmentation. Controlled trials of promising treatment options are important although challenging in this small patient population.

Serum 25-hydroxyvitamin D in erythropoietic protoporphyria.

BACKGROUND: Vitamin D, produced by the action of sunlight on skin, is an important hormone for calcium homeostasis and has been implicated as tumour-protective agent. Some previous studies of photosensitive patients who actively avoid sunlight have failed to show convincing evidence of vitamin D insufficiency. OBJECTIVES: The aim of this study was to characterize the vitamin D status of a large cohort of patients with erythropoietic protoporphyria (EPP). METHODS: U.K. patients with EPP were recruited prospectively and seen locally by a single study investigator. A blood sample was taken for vitamin D assay. All blood analyses were performed in the same laboratory. RESULTS: A cohort of 201 patients with known EPP was seen over a 7-month period between January and July. Thirty-four patients (17%) were deficient in vitamin D and 126 (63%) had insufficient vitamin D. Both insufficiency and deficiency were significantly associated with the total erythrocyte protoporphyrin concentration and inversely with the time in minutes to the onset of symptoms following sunlight exposure. CONCLUSIONS: This is the first report of significant levels of vitamin D deficiency and insufficiency in a large cohort of patients with a photodermatosis. Such individuals are at risk of associated adverse events. In future, clinicians should consider monitoring 25-hydroxyvitamin D levels and instigating oral supplementation or dietary advice if appropriate.

Variable effects of beta-carotene therapy in a child with erythropoietic protoporphyria.

UNLABELLED: Erythropoietic protoporphyria (EPP) is an inborn error of heme biosynthesis with high levels of protoporphyrin in red cells and is characterized by mild to moderate photosensitivity. High-dose beta-carotene therapy has been reported to afford photoprotection in patients with EPP. We report the case of a 5-year-old Caucasian female with EPP who presented with a long-standing 3-year history of recurrent facial blisters and erythematous swelling and lesions of other sun-exposed areas of the skin. She was treated with a topical sunblocker (PreSun Ultra-SP45) but continued to show moderate to severe photosensitivity despite 3 months (March to May) of vigorous photoprotection. She was then started on increasing doses of beta-carotene (90-180 mg/day) over a period of 3 months (June to September) which resulted in a marked improvement of both facial and forearm lesions, but only modest improvement in her hand lesions. CONCLUSION: High-dose beta-carotene appears to provide photoprotection in erythropoietic protoporphyria, resulting in improved but highly variable tolerance to sunlight.