The common pathogens of external auditory canal furuncle are Staphylococcus aureus, Streptococcus, Pseudomonas aeruginosa and Proteus. Furuncle of external auditory canal is a localized acute suppurative inflammation of the skin of cartilage segment of external auditory canal. Most pathogenic bacteria are caused by staphylococci invading hair follicles and dermal glands, which is a frequently-occurring disease, especially in summer. Furuncle of external auditory canal, also known as localized otitis externa, is caused by hair follicle infection in cartilage of external auditory canal. Most are single or multiple. The main symptom is severe ear pain, especially when chewing with your mouth open, which often radiates to your head. There are a lot of uncomfortable feelings or elevated body temperature. If the boil is large enough to block the external auditory canal, hearing loss may occur, and the symptoms will be alleviated if the boil is broken. Furuncle of external auditory canal can be divided into two categories: one is localized otitis externa; The other is diffuse inflammation of the external auditory canal skin, also known as diffuse otitis externa. External auditory canal skin trauma or local resistance reduction is easy to occur, such as ear digging, swimming into the water, long-term pus stimulation suppurative otitis media and so on. In addition, people with allergies and diabetes are prone to recurrent attacks. Common pathogens are Staphylococcus aureus, Streptococcus, Pseudomonas aeruginosa and Proteus. Furuncle of the external auditory canal occurs in the external auditory canal, showing redness, swelling and pain, with a diameter of only 2cm. After suppuration, its center is white at first, and it fluctuates slightly when touched; Then rupture pus, yellow and white pus thrombus appeared. After the pus suppository falls off and the pus flows out, the local swelling can heal. Some boils of the external auditory canal have no pus plug (so-called headless boils of the external auditory canal), and they collapse a little late, so we should try to urge them to discharge pus. Furuncle on the face and external auditory canal is often serious, with a large range of redness and swelling, which is easy to be accompanied by symptoms such as chills, fever and headache. When the furuncle of the external auditory canal around the nose, upper lip and (called "danger triangle") is aggravated or bulged, bacteria can enter the skull through the internal vein and eye vein, causing intracranial purulent infection, which is manifested as fever, headache, vomiting and unconsciousness. Furuncle of external auditory canal occurs in several places at the same time, or repeatedly in a period of time, which is called furuncle of external auditory canal. It is related to patients with low anti-infection ability (such as diabetes), or unclean skin and frequent abrasions (such as some children), but there are also people with unknown reasons. Skin abrasions and ulcers are prone to infection, and ear digging is a common cause. People with diabetes, chronic constipation and physical weakness are prone to this disease and are prone to relapse. High temperature and humidity will reduce the anti-infection ability of external auditory canal, so it is easy to get sick in summer, often because of staphylococcal infection. The external auditory canal is one of the parasitic parts of Pseudomonas aeruginosa, so more than 70% patients with otitis externa can be caused by Pseudomonas aeruginosa. Pathological changes were acute suppurative inflammation, including hyperemia, exudation and neutrophil aggregation. Then destroy cells, destroy tissues, and add pathogens to form amines. Due to the toxicity of coagulase contained in Staphylococcus aureus, the formation of pus thrombus is a feature of Staphylococcus aureus infection focus. When the external auditory canal boils, the earache is severe, which is aggravated when chewing with the mouth open, and can radiate to the ipsilateral head. Feel unwell all over, and your body temperature may rise slightly. When swelling seriously blocks the external auditory canal, tinnitus and hearing loss may occur. Examination showed auricle traction pain, tragus tenderness and localized swelling and swelling of cartilage skin of external auditory canal. After swelling and rupture, pus accumulates in the external auditory canal and flows out of the ear. At this time, the earache will be relieved. Severe furuncle on the posterior wall of external auditory canal can make the posterior auricular sulcus and mastoid area red and swollen, which should be differentiated from acute mastoiditis. Most patients with acute mastoiditis have a history of acute or chronic suppurative otitis media, with obvious fever and no auricle traction pain, but the mastoid part is tender; Tympanic membrane perforation or tympanic membrane is obviously congested with more pus. Acute diffuse otitis externa is characterized by earache and secretion. The examination also showed auricle traction pain and tragus tenderness, diffuse swelling and swelling of the skin of the external auditory canal, accumulation of secretions on the wall of the external auditory canal, narrowing of the lumen of the external auditory canal and swelling of lymph nodes around the ear. Chronic ear itching, a small amount of exudate. The skin of the external auditory canal is thickened, chapped and peeled, and secretions accumulate, which may even lead to the stenosis of the external auditory canal.