Differential histopathological and immunohistochemical findings between palmar psoriasis and chronic hand eczema

Background The differential diagnosis between palmar psoriasis (PP), chronic hand dermatitis (CHE), and hyperkeratotic hand dermatitis (HHD) is challenging. Objectives We sought to distinguish the histopathological and immunohistochemical characteristics between PP, CHD, and HHD. Materials & Methods Hands, clinically diagnosed with PP, CHD, or HHD, were further evaluated using skin biopsy sections based on haematoxylin and eosin staining and immunohistochemical analysis for beta-defensin 2 and interleukin-36 gamma. Results Confluent parakeratosis, absent granular layer, and psoriasiform epidermal hyperplasia were more common in PP and HHD relative to CHE. The level of beta-defensin 2 expression in the stratum corneum and interleukin-36 gamma in the stratum granulosum was higher in PP and HHD relative to CHD. Conclusion Considering the similarities of histopathological and immunohistochemical findings, HHD may be an inflammatory disorder with a pathogenesis similar to that of PP, rather than CHD.