Chronic Alcohol Consumption Exacerbates the Severity of Psoriasiform Dermatitis in Mice

Background A relationship between alcohol consumption and psoriasis has been reported, but it is unclear whether alcohol consumption aggravates psoriasis. Here, we studied the effect of chronic ethanol (EtOH) consumption in the murine model of Aldara‐induced psoriasiform dermatitis. Methods C57BL/6 mice received 5% EtOH in their drinking water for 10 weeks. Dermatitis was induced from weeks 9 to 10, by applying Aldara to the shaved patch of skin on the back. Inflammation was characterized by histological and transcriptomic analyses. Results EtOH consumption aggravated Aldara‐induced dermatitis. The scales were more severe, epidermal thickening was more pronounced, and cutaneous expression of Th17‐related cytokines was exacerbated. Control mice simply receiving EtOH displayed minimal cutaneous inflammation, characterized by epidermal infiltrates of T lymphocytes and the overexpression of IL‐17A and the Th17‐recruiting chemokine CCL20. In vitro studies showed that low concentrations of EtOH induce the expression of CCL20 by murine epidermal keratinocytes. Conclusion Alcohol consumption leads to subliminar skin inflammation, which is revealed by the exacerbation of Aldara‐induced experimental psoriasiform dermatitis, likely through Th17‐type minimal skin inflammation. These results favor the systematic management of alcohol consumption in psoriatic patients. Psoriasis is a Th17‐type archetypal disease. Aggravation of psoriasis by alcohol consumption is uncertain. In the imiquimod‐induced model of psoriasis, mice fed ethanol displayed more severe dermatitis. Ethanol consumption induced epidermal infiltrates of T lymphocytes and overexpression of Th17‐type cytokines. Keratinocytes cultured with ethanol overexpressed CCL20, a Th17‐recruiting chemokine. These results support the deleterious effect of alcohol consumption in psoriasis by upregulating Th17 inflammatory process, and favor the systematic management of alcohol abuse in psoriatic patients.