Retrospective study of intraepidermal nerve fiber distribution in biopsies of patients with nummular eczema

Background: Nummular eczema is a chronic inflammatory condition characterized by pruritus and histologically characterized by spongiosis. The etiology is unknown, and the lesions frequently arise spontaneously. Neuropeptides contribute to mediating and maintaining eczematous conditions. Previous research indicates that the number of immunoreactive nerve fibers is increased in pruritic skin lesions. Objective: We sought to determine if the number of immunoreactive nerve fibers is increased in nummular eczema, as in other inflammatory pruritic conditions. Methods: Protein gene product 9.5 (PGP 9.5) was assessed by immunohistochemistry in 22 biopsies of nummular eczema and was compared with immunohistochemical expression of 8 skin biopsies uninvolved by nummular eczema. Results: Nerve fiber distribution using PGP 9.5 stain showed that there was significantly reduced PGP9.5 stain amount in the epidermis of patients with nummular eczema compared with their respective healthy control (P = 0.0054). However, no statistical difference was seen in the papillary dermis. Conclusion: Pruritus of nummular eczema is not associated with an increase of epidermal nerve fiber density and sprouting.