REFERRAL FOR SUN ALLERGY – A CASE OF ERYTHROPOIETIC PROTOPORPHYRIA

Abstract

<h3>Introduction</h3> Erythropoietic protoporphyria (EPP) is an inherited cutaneous porphyria characterized by painful, non-blistering photosensitivity usually noted in early childhood and occurring acutely after sunlight exposure. Cutaneous lesions develop within minutes of sun exposure with diffuse edema of the skin in sun-exposed areas, resembling angioedema. EPP is now recognized as the most common porphyria in children and the third most common in adults. In the review of over 100 cases in the United States, the average delay diagnosis of EPP was 13 years. <h3>Case Description</h3> A 29-year-old female with a PMH of polyglandular autoimmune disease presented to the Allergy clinic as a referral for "Sun Allergy". The patient reported a near lifelong history of a photosensitive rash. The rash typically begins 10-20 minutes after sun exposure, sparing covered areas. The rash is described as burning/stinging in nature, a 10/10 on the pain scale. She additionally reported intermittent, small bullae in affected areas. She denied pruritus and urticaria. Patient denied recent NSAID and antibiotic use. She denied the use of topicals, including sunscreen. Patient has one full sibling with a similar clinical course. Patient denied history of substance use disorder. Porphyria became the leading differential diagnosis. Serum porphyrins with reflex porphyrins were obtained and indicated elevated total serum porphyrins with notable reflex indicating elevated protoporphyrins. The patient was diagnosed with Erythropoietic Porphyria and referred to Dermatology for further management. <h3>Discussion</h3> This case highlights the importance of including porphyrias in the differential diagnosis of photosensitive rashes, which may be referred to Allergy and Immunology clinics for evaluation.