Topical cis-urocanic acid attenuates oedema and erythema in acute and subacute skin inflammation in the mouse

Summary Background cis‐Urocanic acid (cis‐UCA) is an endogenous immunosuppressive molecule of the epidermis. Objectives We investigated the effects of topical cis‐UCA creams (2·5% and 5%) in acute and subacute mouse models of skin inflammation. Methods Acute skin irritation was induced by applying dimethyl sulphoxide (DMSO) on the earlobe of CD‐1 mice. Topical cis‐UCA, hydrocortisone (1%) or tacrolimus (0·1%) were applied 10 min later. In another model, subacute inflammation was provoked and maintained by three applications of 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) on the ears of NMRI mice on days 1, 2 and 4. The test products were applied topically twice a day during 6 days. Results In the acute DMSO model, cis‐UCA creams suppressed ear swelling at 1 h significantly more efficiently than hydrocortisone (P