dermatitis - inflammation of the skin; can be caused by contact with many commercial substances, including petroleum products. Oil and grease in contact with the skin can result in plugging of sweat glands and hair follicles or defatting of the skin, which can lead to dermatitis. Dermatitis can be prevented in such cases by avoiding contact with the causative substances, or, if contact occurs, by promptly washing the skin with soap, water, and a soft skin brush. Clothes soaked with the substance should be removed, and laundered before re-use.