Demodex is a chronic inflammation caused by Demodex parasitizing in human hair follicles or sebaceous glands, also known as folliculitis. It often occurs in adults over 30 years old and rarely in children. The percentage of occurrence in adults varies, ranging from 10% to 27%. But its presence is often not obvious unless there are a large number of them. Demodex mites are slender, worm-like, about 0.9mm long, and parasitize the sebaceous glands of the nose, followed by the forehead, jaw, and scalp. It can cause the parasitic hair follicles to swell and the secretion of the sebaceous glands to increase. Its life cycle lasts 14 days, 60 hours for eggs, 36 hours for larvae, 132 hours for several pupal stages, and 120 hours for adults.