The histamine‐synthesizing enzyme histidine decarboxylase is upregulated by keratinocytes in atopic skin

Abstract

Keratinocytes express abundant HDC protein, and the levels increase in atopic skin. LPS, HDM and cytokines, which are implicated in allergic inflammation, promote the expression of the enzyme and upregulate histamine levels in keratinocytes. Actively produced histamine influences keratinocyte differentiation, suggesting functional relevance of the axis to atopic dermatitis. The findings therefore identify a new point of therapeutic intervention.