The pathogenic factors and pathogenesis of this disease are possibly related to allergic reaction, endocrine disorder, metabolic disturbance, and indigestion, etc. The disease belongs to "Bichuang" (nasal sore) in TCM according to  its  clinical  manifestations.  Its pathogenic factors are mainly related to stagnated heat of lung meridian as well as dampness and heat of the spleen and stomach at the acute stage and to blood deficiency at the chronic stage. When stagnated heat of lung meridian or dampness and heat of the spleen and stomach rises to invade the nose, skin ulceration will occur in the patients with acute onset in most cases; when blood deficiency generates wind and transforms into dryness, nasal skin will lose its nourishment, giving rise to the disease at the chronic stage on most occasions. This is the pathogenesis of the disease.

1. Syndrome of stagnated heat of lung meridian
Main symptoms and signs: Local itch, burning sensation and red swelling of the nasal vestibule which is painful after ulceration due to the scratch, feverish body, thirst with inclination to drink, dark urine, dry stool, reddish tongue with yellowish fur and rapid pulse.

2. Syndrome of dampness and heat of the spleen and stomach
Main symptoms and signs: More local blisters of the nasal vestibule with damp exudate which is not easily dry, mild pain, severer itch, reddish tongue with yellowish greasy fur, thready and weak pulse.

3. Syndrome of blood deficiency transforming into dryness
Main symptoms and signs: Longer course of illness, itching, dry and thickened skin of the nasal vestibule with lichenification, reddish tongue with whitish thin fur, thready and weak pulse.