Redness, swelling and pain at the nostrils may be caused by nasal vestibulitis, nasal vestibular boils, nasal septum abscess and so on. 1. Nasal vestibulitis: Nasal vestibulitis is usually caused by repeatedly picking the nose with dirty hands, which leads to secondary infection and inflammation, causing redness, swelling and pain at the nostrils. 2. Nasal vestibular boils: Nasal vestibular boils are formed after the inflammation of the nasal vestibule is limited, which is manifested as redness, swelling and pain in the localized area of the nasal vestibule. 3. Nasal septum abscess: Nasal septum abscess is mainly the accumulation of pus under the cartilage membrane or periosteum of the nasal septum, which is often secondary to hematoma and infection of the nasal septum after trauma or surgery. Common manifestations are redness, swelling and pain at the bridge or tip of the nose. There are many reasons for the redness, swelling and pain at the nostrils, and it is recommended that patients should consult a doctor in time to clarify the cause of the disease and take effective treatment under the guidance of the doctor.