Updated project metadata. Low environmental humidity aggravates symptoms of inflammatory skin diseases, e.g. of Atopic Dermatitis (AD). Using mice that develop AD-like symptoms, we show that an increase in environmental humidity rapidly rescues their cutaneous inflammation and associated epidermal abnormalities. Quantitative proteomics analysis of epidermal lysates of mice kept at low or high humidity identified novel humidity-regulated proteins, including Clca2/Clca3a2, a protein with previously unknown function in the skin.