Acne under the nose may be caused by acne vulgaris, perioral dermatitis, folliculitis and other diseases. 1. Acne vulgaris: mainly related to the increase of androgen level and sebum secretion, there are symptoms of pimples, papules and pustules, which are manifested as pimples under the nose. 2. Perioral dermatitis: it occurs in the perioral area, chin and the side of the nose, which may be related to the long-term use of topical glucocorticoids, fluoride toothpaste, etc., and the patient will have pimples under the nose. 3. Folliculitis: red pimples may appear in the beard area, related to bacterial and fungal infections triggering inflammation, patients may have symptoms of pimples under the nose. There are many reasons for the appearance of pimples under the nose, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease, under the guidance of the doctor standardized treatment.