Intraepidermal nerve fibre density is decreased in lesional and inter-lesional prurigo nodularis and reconstitutes on healing of lesions

Abstract

Prurigo nodularis (PN) is characterized by the presence of intensely itchy nodules and papules, which are frequently refractory to therapy (1). The results of previous morphological studies indicate that nerve fibres have an important function in PN; in support of this, a dermal neuronal hyperplasia was observed in immunohistochemical studies (2, 3), although this could not be confirmed in histological analysis (4). As intraepidermal nerve fibres have been identified to be of great importance for the sensation of pruritus (5), we investigated them in PN (6). Surprisingly, decreased intraepidermal nerve fibre density (IENFD) independent of clinical parameters was found (6). With this, we hypothesized that reduced nerve fibre density might be due to scratching and, accordingly, that hypoplasia normalizes during healing of PN. To further investigate the role of nerve fibres in PN, we examined the IENFD of PN at different stages.