Perioral dermatitis is an inflammatory skin reaction that occurs around the mouth and is most common in children and adult women and may be related to irritation from saliva, food or fluoride toothpaste, light, etc. Perioral dermatitis has two prevalent groups, one is children around half a year old, which may be associated with frequent drooling, while just being exposed to complementary foods, especially acidic foods such as fruits, such as mangoes, both of which repeatedly irritate the perioral skin causing perioral dermatitis. The other is in adult women, 25-45 years old, and may be related to UV light, fluoride toothpaste, lipstick, mites, etc. There is little difference in treatment, topical hydrocortisone butyrate cream or Denide cream, once a day during the day, and 0.03% tacrolimus ointment, once a day at night. Live with avoidance of bad stimuli such as saliva, food and toothpaste, and try to eat with a spoon and straw, all fed into the mouth. Use more petroleum jelly and lanolin to enhance local moisturizing at regular times. For adult women, tetracycline may be added orally as appropriate, and mite screening (which can be done by microscopic examination) can be actively improved. Perioral dermatitis is a multifactorial, inflammatory disease with an eventual rash manifesting itself in the perilabial area, which can be pruritic and painful to some extent and can accumulate in the nasolabial folds and nose in severe cases. Skin patch test can be done to actively seek and remove the causative agent, as well as symptomatic treatment to relieve the symptoms.