moon face [AS, mona, moon; L, facies, face] , a condition characterized by a rounded, puffy face. It occurs in people treated with large doses of corticosteroids, such as those with chronic asthma, rheumatoid arthritis, or acute childhood leukemia. The features return to normal when the medication is stopped. Moon face is symptomatic of Cushing’s disease and Cushing’s syndrome. Also called moon facies. See also Cushing’s disease, Cushing’s syndrome.