Perioral dermatitis, a rash presenting red bumps around the mouth, under the eyes, on the forehead and on the chin, also affects the folds of the nose, according to Healthline. Another cause of a rash under the nose that especially affects children is impetigo, states the American Osteopathic Association.
While the cause of perioral dermatitis is unknown, evidence suggests topical steroids and certain cosmetics, such as those with petrolatum or a paraffin base, may result in the condition, explains Healthline. Bacterial or fungal infections, oral contraceptives and certain sunscreens are also triggers. Treatments for the condition include discontinued use of products that cause the rash and topical or oral antibiotics. Those suffering from perioral dermatitis should avoid the use of nasal or topical steroids, as these can complicate the condition.
Impetigo presents crusty, honey-colored sores, often on the face between the upper lip and nose, but may also spread to other parts of the body and is highly contagious, notes the American Osteopathic Association. Impetigo results from either the streptococcus or staphylococcus bacteria and often begins in a small cut or scratch. Steps for preventing and treating impetigo include keeping the skin or affected area clean and applying antibiotic ointments.