There are many reasons for red nose hair, such as rosacea, environmental stimulation, infectious factors, allergic factors and so on. 1. rosacea: rosacea can cause capillary expansion of the nose head, so it will lead to the phenomenon of red nose hair. Although the disease may have something to do with mite infection, it is not infectious, but due to the expansion of capillaries. 2. Environmental stimulation: the nose head suffers from high temperature stimulation, cold stimulation, frostbite and other factors, can also lead to nose hair red. 3. Infectious factors: Bacterial and viral infections can also cause boils, nasal vestibulitis, cellulitis and other diseases on the nose head, so it may show red nose hair. 4. Allergic factors: People with allergies may experience allergic reactions to redness, itching and rashes when they come into contact with allergens. There are many causes of nose hair redness, after the symptoms, it is recommended to go to the hospital in a timely manner to improve the examination, after a clear diagnosis to give standardized treatment, do not ignore the symptoms, to take it lightly.