Renal Involvement in Epidermolysis Bullosa Simplex: An Unusual Presentation

To the Editor: Epidermolysis bullosa (EB) includes a heterogeneous group of congenital, hereditary blistering disorders [1]. There are few reports of its association with renal dysfunction. We report a case of epidermolysis bullosa simplex (EBS) with persistent proteinuria detected to have IgA nephropathy on renal biopsy. A 4-yold developmentally normal boy born to consanguineous parents, who was diagnosed to have EBS in the neonatal period, developed anasarca since 1 wk. There was history of two similar episodes of edema with proteinuria, treated with diuretics elsewhere. He did not have nail, hair or mucosal surface involvement. He had past history of recurrent pus discharge from the bullous lesions, resolving with cloxacillin. Examination revealed multiple flaccid bullae, some with purulent discharge and post-inflammatory hyperpigmentation. There were no areas of scarring. The child had proteinuria (2+; urine protein: creatinine ratio 0.5) with microscopic hematuria. Blood urea was 35 mg/dL, serum creatinine 0.7 mg/dL, serum cholesterol 167 mg/dL, serum albumin 3.1 g/dL; Anti-streptolysin O and C3 levels were normal. Skin biopsy revealed subepidermal bulla with Laminin 5 staining expression (Fig. 1). Ultrasound showed normal renal system. Histopathological examination and immunofluorescence of the renal biopsy showed IgA nephropathy with mesangioproliferative glomerulonephritis (Fig. 1). Treatment with enalapril led to improvement in proteinuria over 3 mo (urine protein: creatinine ratio 0.23). EB has 4 major variants: EBS, junctional EB [JEB], dominant dystrophic EB [DDEB], and recessive dystrophic EB [RDEB] [1]. Our patient had clinical (absence of scarring ; non-involvement of nails or mucosal surfaces) and histopathological evidence of EBS. Laminin-5 expression is absent in JEB [2]. Renal dysfunction in EB, may be due to skin infections leading to poststreptococcal glomerulonephritis, IgA mesangiopathy or amyloidosis [3]. There is paucity in literature of EB in association with IgA nephropathy, with RDEB, DDEB and JEB subtypes reported previously [2, 4, 5]. Our patient had a different variant (EBS). Although intuitively,