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Dermatopathology: Practical & Conceptual

October – December 2010 | Volume 16, No. 4

Epidermolysis bullosa pruriginosa—case series of two sporadic cases and one family

Ahmed, Elshahat Farag; Fawzy, Mohamed; Selim, Mohammed

Introduction

Epidermolysis bullosa pruriginosa (EBP) is a rare distinct variant of dystrophic epidermolysis bullosa (DEB), which was first described in 1994 by McGrath et al. [1] It is characterized clinically by intense pruritus and hypertrophic scarring. All forms of DEB, including EBP, result from mutations in the type VII collagen gene, COL7A1. [2] Most cases are sporadic, less commonly autosomal dominant, and rarely autosomal recessive inheritance are found. [1,3,4] Microscopic studies of EBP show typical findings of DEB [5] and it has been postulated that itching lesions of EBP could represent an abnormal dermal reactivity of some subjects to their inherited bullous disorder.

The study of the molecular basis of classical dominant DEB and EBP shows that both diseases are caused by a missense glycine substitution mutation by different amino acids in the same codon of COL 7A (G2028R and G2028A). [2,6,7] Intriguingly, the spectrum of COL7A1 mutations underlying EBP is not significantly different from that in non-itchy forms of DEB. [8] The reason for the itchy skin phenotype is unclear and the cause of the pruritus cannot be attributed to a specific type of COL7A1 mutation. Previous studies have assessed and excluded causes such as atopy, raised IgE levels, iron deficiency, renal, liver, and thyroid dysfunction, matrix metalloproteinase gene polymorphisms, and filaggrin gene mutations as potential modifiers of phenotype. [4,9]

Here we present two sporadic cases and one family with autosomal dominant inheritance of EB pruriginosa.

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