Topical cholesterol treatment ameliorates hapten‐evoked cutaneous hypersensitivity by sustaining expression of 11β‐HSD1 in epidermis

Changes in the stratum corneum extracellular matrix impair epidermal barrier function and may cause dermatoses. The aim of this study was to examine the effect of exogenous cholesterol application on skin barrier function and cutaneous inflammation. Skin barrier‐disrupted or hapten‐stimulated mice were treated with topical cholesterol. The effect of topical cholesterol application on an oxazolone (OXA)‐induced hypersensitivity reaction was evaluated. Topical application of cholesterol efficiently decreased transepidermal water loss in areas of barrier‐disrupted skin and ameliorated OXA‐induced cutaneous hypersensitivity. These favourable effects may have resulted from sustained expression of 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1) in the cholesterol‐treated skin. As 11β‐HSD1 is known to produce active cortisol, topical cholesterol may attenuate contact hypersensitivity by normalizing secretion of hormonally active cortisol from the skin.