Eur J Pediatr (2008) 167:703–706 DOI 10.1007/s00431-007-0557-1 SHORT REPORT Erythropoietic protoporphyria without skin symptoms-you do not always see what they feel Anne L. Y. Lecluse & Veronica C. M. Kuck-Koot & Huib van Weelden & Vigfus Sigurdsson & Ingrid M. Russel & Jorge Frank & Suzanne G. M. A. Pasmans Received: 21 February 2007 / Accepted: 18 June 2007 / Published online: 21 August 2007 # Springer-Verlag 2007 Abstract Erythropoietic protoporphyria (EPP) is an inherited disorder of the porphyrin metabolism that often remains undiagnosed in children. We report on a 4-year-old girl who had been suffering for 1 year from recurrent painful crises affecting her hands, feet, and nose following sun exposure. Objective skin lesions were absent until the age of 6. Porphyrin analysis revealed elevated free erythrocyte protoporphyrin (FEP) levels confirming the diagnosis of EPP. This illustrates that skin lesions might be completely absent in children affected with EPP, a fact that has only been reported once previously. Because EPP can manifest with few and unspecific cutaneous symptoms or no skin lesions at all, like in this patient, the diagnosis of A. L. Y. Lecluse : V. C. M. Kuck-Koot (*) : H. van Weelden : V. Sigurdsson : S. G. M. A. Pasmans Department of Dermatology and Allergology, Wilhelmina Children’s Hospital, University Medical Centre, G02.124, P.O. Box 85500, 3508 GA Utrecht, The Netherlands e-mail: v.c.m.kuck@umcutrecht.nl I. M. Russel Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Centre, G02.124, P.O. Box 85500, 3508 GA Utrecht, The Netherlands J. Frank Department of Dermatology, University Hospital Maastricht, Maastricht, The Netherlands J. Frank Maastricht University Centre for Molecular Dermatology (MUCMD), University Hospital Maastricht, Maastricht, The Netherlands J. Frank Euregional Porphyria Centre Maastricht-Aachen (EPCMA), University Hospital Maastricht, Maastricht, The Netherlands EPP might be delayed or missed. EPP should be excluded in all photosensitive children, especially when discomfort is disproportionate to the extent of the cutaneous lesions. The clinic, pathophysiology, diagnosis, complications, and therapy of EPP are discussed. Keywords Porphyrias . Erythropoietic protoporphyria . Ferrochelatase . Photosensitivity Abbreviations EPP erythropoietic protoporphyria FECH ferrochelatase ROS reactive oxygen species FEP free erythrocyte protoporphyrin UV ultraviolet UVB ultraviolet-B ALA δ-aminolevulinic acid Introduction Erythropoietic protoporphyria (EPP) (OMIM 177000) results from a partial deficiency of ferrochelatase (FECH), the last enzyme in heme biosynthesis that is located in the mitochondrium [10, 13]. FECH catalyzes the insertion of iron into protoporphyrin IX to form heme (Fig. 1) [10]. Although overall EPP is a rare disease, it is the most common type of porphyria manifesting in childhood with an estimated prevalence of 1 in 130,000 [10, 13, 23]. The disease has no racial or sex predilection and no precipitating factors have been described to date [10, 20]. The major clinical feature of EPP is cutaneous photosen- sitivity that usually commences early in infancy or childhood, affects the sun-exposed body sites, and worsens