Rosacea and seborrheic dermatitis may be the cause of the redness on the nose. 1. Rosacea: Rosacea may be related to heredity, neurovascular dysfunction, damage to the skin barrier function, immune inflammatory response, etc. It occurs in the middle of the face and is mainly characterized by redness of the skin as well as erythema, papules, pustules, and capillary dilatation. 2. Seborrheic dermatitis: Seborrheic dermatitis may be related to heredity, microbial infections and other factors, and it occurs in the head, face, chest and back, etc. It mainly manifests as erythematous rashes on the surface of the skin, greasy, flaky, itchy and other symptoms. Nose erythema may also have other causes, it is recommended to go to the hospital in a timely manner to improve the examination, to clarify the cause of the disease to give targeted treatment.