Nose odor may be caused by rhinitis, sinusitis, tumors of nasal cavity and paranasal sinuses, upper respiratory tract inflammation and lower respiratory tract lesions.

There is a thin and tender mucosa in the nostril (nasal cavity), and there are black hairs in the front of it, which can block the dust and impurities in the air; There are many capillaries in it, which can make the inhaled air close to body temperature, secrete mucus, make the air moist and adhere to dust bacteria in the air. So the nasal cavity is the first "defense line" of the respiratory system. Picking your nose with your hand will destroy the function of this "defense line"; Nails are easy to dig through the nasal mucosa, so that bacteria attached to nails can easily invade the nasal mucosa, causing inflammation, bleeding and even suppuration. The veins of the nasal cavity are connected, and the area around the nose is called the "danger triangle" in medicine. If bacteria invade the cranial cavity and cause infection and suppuration, it will be life-threatening, so don't let children pick their noses.