Bullous dermatoses in end-stage renal failure: porphyria or pseudoporphyria?

Pseudoporphyria: An Atypical Variant Resembling Toxic Epidermal Necrolysis

Background:

Pseudoporphyria has been attributed to both medication usage and chronic hemodialysis. Histologically, it is identical to porphyria cutanea tarda. It is most commonly seen as localized bullae on sun-exposed skin, often on the dorsum of the hands and fingers.

Objectives:

We describe a 31-year-old man with rapidly evolving bullae which became denuded, clinically suggestive of toxic epidermal necrolysis. Pseudoporphyria was proven histologically. However, our patient's eruption was not localized as small bullae but was widespread, with large bullae evolving into large, cutaneous, denuded erosions.

Conclusions:

We describe a previously unreported, generalized variant of pseudoporphyria that resembles toxic epidermal necrolysis. We provide a review of pseudoporphyria and compare our variant to toxic epidermal necrolysis and mimicking disorders.

Pseudoporfiria induzida pela diálise tratada com N-acetilcisteína oral

Pseudoporfiria é dermatose bolhosa rara, semelhante clínica e histopatologicamente à porfiria cutânea tardia. Acomete, principalmente, pacientes renais crônicos em diálise peritoneal ou hemodiálise. Medicamentos também podem ser envolvidos na etiologia. O diagnóstico e o manejo desta entidade é um desafio para os dermatologistas. Os autores demonstram um caso de pseudoporfiria, relacionada à diálise, com evolução favorável após o uso de N-acetilcisteína oral.

Bullous skin lesions in a patient undergoing chronic hemodialysis

Porphyria cutanea tarda (PCT) is a vesiculobullous skin disorder characterized by a defect in heme biosynthesis. Reduced activity of the hepatic enzyme uroporphyrinogen decarboxylase (URO-D) results in accumulation of photosensitive porphyrins; this ultimately leads to the skin fragility and blistering that is characteristic of this disease. The majority of cases of PCT are associated with acquired deficiencies of the enzyme URO-D, secondary to hepatic injury precipitated by medications or infections. Less commonly, PCT has been documented in patients with end-stage renal disease. The pathogenesis of PCT in long-term hemodialysis (HD) has been attributed to many factors, but the following mechanisms have been implicated: (i) decreased hepatic URO-D activity due to suppressive effects of iron and other hepatotoxins and (ii) poor porphyrin clearance by renal replacement therapies. We report a case of PCT that developed in a patient on maintenance HD for 4 years. He had a history of hepatitis C and evidence of iron overload. However, as the patient was anemic, therapeutic phlebotomy was problematic and therefore erythrocyte-stimulating agents were maximized to mobilize iron stores and allow phlebotomy. With this treatment, the patient's skin lesions improved in conjunction with decreasing ferritin levels.

Skin problems in chronic kidney disease

Skin disorders associated with chronic kidney disease (CKD) can markedly affect a patient's quality of life and can negatively impact their mental and physical health. Uremic pruritus, which is frequently encountered in patients with CKD, is considered to be an inflammatory systemic disease rather than a local skin disorder. Biomarkers of inflammation are increased in patients with uremic pruritus and an imbalance of the endogenous opioidergic system might be involved in the complex pathogenesis of the disease. Treatment options for uremic pruritus include emollients, topical capsaicin cream, ultraviolet B phototherapy, gabapentin, oral activated charcoal and nalfurafine, a kappa-opioid-receptor agonist. Calcific uremic arteriolopathy is triggered by an imbalance of promoters and inhibitors of vascular calcification, caused by the inflammatory changes that occur in uremia. Promising therapeutic strategies for calcific uremic arteriolopathy include bisphosphonates and intravenous sodium thiosulfate. Nephrogenic systemic fibrosis is a devastating condition associated with the use of gadolinium-based contrast agents in patients with CKD. At present, no therapies are available for this complication. Preventive measures include use of iodine-based contrast agents, particularly in patients with CKD stage 4 and 5. If gadolinium contrast is necessary, administration of low volumes of the more stable macrocyclic ionic types of gadolinium-based contrast agent is advocated. Hemodialysis following gadolinium exposure might offer benefits but evidence is lacking.

Cutaneous manifestations of chronic kidney disease

Among the most common systemic diseases associated with cutaneous manifestations is kidney failure. Most of these occur in the setting of chronic kidney disease. In the following review, we will target 6 of these conditions in details. The entities are as follows: pruritus acquired perforating dermatoses, nail disorders, bullous disorders, calciphylaxis, and nephrogenic fibrosing dermopathy.

A case of haemodialysis-associated pseudoporphyria successfully treated with oral N-acetylcysteine

We report a 33-year-old woman with haemodialysis-associated pseudoporphyria successfully responding to treatment with oral N-acetylcysteine. We briefly review the current literature on bullous skin disorders in end-stage renal disease, and compare and contrast the pathogenesis of pseudoporphyria and porphyria cutanea tarda in this context. We also discuss the antioxidant properties and clinical applications of N-acetylcysteine, including the treatment of haemodialysis-associated pseudoporphyria.

[Porphyria cutanea tarda in a dialyzed female patient]

Dermatological disorders are a frequent finding in patients with renal insufficiency. Porphyria cutanea tarda, pseudoporphyria, phototoxicity or concurrent bullous diseases may cause the appearance of lesions with liquid content in patients in dialysis. We describe the case of a female patient in dialysis who developed bullous lesions. The clinical and laboratory findings were initially compatible with the suspicion of pseudoporphyria, but the finding of some frankly elevated levels of porphyrins in serum, urine and feces confirmed the diagnosis of porphyria cutanea tarda. Porphyria cutanea tarda and pseudoporphyria present with common clinical manifestations. However, the levels of porphyrins in plasma, urine and feces in pseudoporphyria are normal or slightly elevated.

Hochdosierte Vitamingabe zur Verhinderung einer Porphyria cutanea urämica?

50 Patients with chronic renal failure undergoing hemodialysis with or without porphyria cutanea tarda (PCT)-like skin changes were investigated. The total porphyrin amount in erythrocytes, plasma and dialysate and the distribution of porphyrin metabolites in plasma and dialysate were measured. In plasma, the group of patients with skin changes (referred as PCU = porphyria cutanea uremica) showed significantly increased uroporphyrin levels as compared to the non-symptomatic group. In addition, significant differences concerning the ratio uro-/coproporphyrin in plasma were shown: non-symptomatic patients with 0.87, as opposed to the PCU group with 3.7. Considerable differences between the level of vitamin ingestion were identified between the groups. Patients with PCU took distinctly less vitamins C, E and B than patients without symptoms.

Porphyrie cutanée tardive chez un hémodialysé ayant une hépatite virale C : efficacité du traitement par petites phlébotomies

INTRODUCTION

Porphyria cutanea tarda (PCT) is a disorder of heme biosynthesis resulting from deficiency in the enzyme uroporphyrinogen decarboxylase. In the sporadic form of PCT, there are many agents that trigger the clinical manifestations.

EXEGESIS

We report a case of PCT in an hemodialysed patient with hepatitis C virus infection (HVC). He was treated with small repeated phlebotomies of 50 ml every week with photoprotection, eviction of traumatismes and inducing drugs. A clinical remission was induced after five months of treatment.

CONCLUSION

A proper diagnosis of PCT in non uremic hemodialysed patients requires fractionation of serum and fecal porphyrin changes. Management of this patients is difficult. Small repeated phlebotomies (50-100 ml) could be an interesting therapy.

ACP Best Practice No 165: front line tests for the investigation of suspected porphyria

The porphyrias are uncommon disorders of haem biosynthesis and their effective management requires prompt and accurate diagnosis. This article describes methods for the determination of urinary porphobilinogen, urinary and faecal total porphyrins, and total porphyrins in erythrocytes and plasma that are suitable for use in non-specialist laboratories. The selection and interpretation of these methods, and the indications for further, more specialised, investigation are discussed.

Pseudoporphyria

Pseudoporphyria is the term used to describe a photodistributed bullous disorder with clinical and histologic features of porphyria cutanea tarda, but without accompanying biochemical porphyrin abnormalities. Medications, chronic renal failure/dialysis, excessive sun exposure and UVA radiation have all been reported to cause pseudoporphyria. Recognition, diagnosis, and appropriate management of pseudoporphyria are discussed.