Beyond the Rash: A Multidisciplinary Approach to Porphyria Cutanea Tarda in a Patient with ESKD on Peritoneal Dialysis

Introduction: Porphyria Cutanea Tarda (PCT) is a rare disorder resulting from deficient activity of uroporphyrinogen decarboxylase (UROD) in the liver. Managing PCT in patients with End-Stage Kidney Disease (ESKD) undergoing Peritoneal Dialysis (PD) involves unique challenges due to overlapping symptoms and the complexities of treatment. Case Description: 55-year-old female with ESKD, stemming from a congenital solitary kidney and chronic pyelonephritis, managed with PD for the past year, presented with a rash on her temple. Initial treatment with prednisone and doxycycline for a suspected insect bite was ineffective. She subsequently developed painful blisters on her hands prompting a dermatological opinion. Skin biopsy showing sub epidermal cell-poor bulla suggestive of PCT. Further evaluation showed elevated total urinary porphyrins (17,863 µg/24h) and erythrocyte porphyrin levels (176 µg/dL) confirming the diagnosis. Her ferrtin levels were also elevated (>4000 ng/mL) suggesting possible underlying Hemochromatosis. Discussion: Diagnosing PCT in ESKD patients is challenging because impaired porphyrin clearance during dialysis necessitates elevated urinary and erythrocyte porphyrin levels for diagnosis. Porphyrin buildup can mimic PCT skin manifestations. High-flux hemodialysis more effectively removes plasma porphyrins than peritoneal dialysis. Phlebotomy is unsuitable for most ESKD patients, making low-dose hydroxychloroquine a viable treatment option. Genetic testing for UROD mutations is crucial to differentiate PCT from hereditary erythropoietic porphyria (HEP), a rare, severe form with biallelic mutations and elevated erythrocyte zinc protoporphyrin. Hemochromatosis should be excluded via HFE gene mutation testing. Multidisciplinary collaboration among dermatology, hematology, and hepatology is essential, and genetic counseling offers insights into managing hereditary implications. This case highlights the diagnostic and therapeutic challenges of managing PCT in an ESKD patient on PD, emphasizing the need for comprehensive genetic testing and tailored management strategies to optimize outcomes. Further research is needed to explore effective treatments and improve porphyrin clearance in this population.