Erythropoietic protoporphyria in the U.K.: clinical features and effect on quality of life

Summary Background Erythropoietic protoporphyria (EPP) is a rare inherited photodermatosis that causes lifelong painful photosensitivity. Neither its full clinical spectrum nor its impact on quality of life (QoL) has been investigated in a large cohort of patients. Objectives To document the clinical features of EPP and its impact on QoL in a high proportion of all patients with EPP resident in the U.K. Methods Patients with EPP were identified from U.K. clinical databases and assessed by the same clinical investigator over a 7‐month period using a standardized proforma and validated adult (Dermatology Life Quality Index, DLQI) and children's (Children's Dermatology Life Quality Index, CDLQI) QoL questionnaires. Results Three hundred and eighty‐nine living patients with EPP were identified, of whom 223 [114 females, 109 males; median age 34 years (range: 5–87), from 193 families] were investigated. Total erythrocyte porphyrin (TEP) was higher in males (median: 25·3 μmol L−1) than females (median: 19·3 μmol L−1). The median ages at onset and diagnosis were 1 and 12 years, respectively. Median times for onset of symptoms after sun exposure, onset of signs (oedema, erythema) and resolution of symptoms were 20 min, 6 h and 3 days, respectively. Most patients reported absence of protection by glass (92%), priming (85%), exacerbation by wind (68%), no family history of photosensitivity (56%), no symptoms during winter (56%) and had chronic skin lesions (79%). Symptoms changed little with age but improved during pregnancy in 47% of gravid women. Most patients used protective clothing and a sunscreen; 28% were taking β‐carotene and a further 56% had taken it; 29% were not under regular medical care. Two patients (1%) had liver failure and 8% reported gallstone disease. QoL was markedly impaired, with scores similar to those in severe dermatological disease (mean DLQI score 14·0, n = 176; mean CDLQI score 12·8, n = 44), indicating a large effect on patients’ lives. DLQI scores correlated weakly with TEP (rs = 0·228; P = 0·002) and time to onset of symptoms (rs = −0·233; P = 0·002) but not with age at onset. Conclusions EPP is a persistent, severely painful, socially disabling disease with a marked impact on QoL. Its diagnosis is often overlooked. None of TEP, age at onset nor time to onset of symptoms is a useful predictor of impaired QoL in individual patients.