External otitis can be divided into localized external otitis, manifested by furunculosis of the external auditory canal; and diffuse external otitis, manifested by diffuse inflammation of the skin or subcutaneous tissue of the external auditory canal.
Etiology
External auditory canal furunculosis is a localized suppurative inflammation of the hair follicles or sebaceous glands in the skin of the external auditory canal. Individuals with diabetes or weak constitution are susceptible to this disease. The pathogen is mainly Staphylococcus aureus, and sometimes Staphylococcus albus.
Diffuse external otitis is a diffuse inflammation of the external auditory canal. Water exposure in the external auditory canal and long-term pus stimulation of suppurative otitis media are the predisposing factors. The disease is prone to occur when there is trauma to the external auditory canal skin or a decrease in local resistance. Individuals with diabetes or allergic constitution are prone to recurrence. Common pathogens include Staphylococcus aureus, hemolytic streptococcus, Pseudomonas aeruginosa, and Proteus.
Clinical manifestations
External auditory canal furunculosis occurs on the cartilage of the external auditory canal. Early symptoms are severe otalgia, aggravated when opening the mouth and chewing, and can radiate to the ipsilateral head. General malaise may be present, and the body temperature may rise slightly. When furunculosis blocks the external auditory canal, there may be tinnitus and aural fullness. Examination shows auricular tenderness, tragal tenderness, and skin furunculosis on the cartilage of the external auditory canal. After the abscess matures and ruptures, thick pus flows out of the external auditory canal, which may be mixed with blood, and otalgia is relieved at this time. Furunculosis on the posterior wall of the external auditory canal may cause redness and swelling in the posterior auricular groove and mastoid area, which can be easily mistaken for mastoiditis, and should be differentiated from acute mastoiditis. Acute mastoiditis often has a history of acute or chronic suppurative otitis media, with significant fever; there are generally not tragal tenderness and auricular tenderness, but mastoid tenderness, tympanic membrane perforation or significant congestion of the tympanic membrane, and some pus; and mastoid x-ray film shows turbidity of mastoid air cells or bone destruction.
Acute diffuse otitis externa is manifested by otalgia, burning sensation, and little secretions. Examination also shows tragal tenderness and auricular tenderness, diffuse redness and swelling of the skin of the external auditory canal, accumulation of secretions in the wall of the external auditory canal, narrowing of the external auditory canal cavity, and swelling and pain of the periotic lymph nodes. Chronic diffuse otitis externa presents with pruritus in the external auditory canal, little exudation, thickened skin of the external auditory canal, cracks, desquamation, accumulation of secretions, and even stenosis of the external auditory canal.
Necrotizing otitis externa is a special type of diffuse otitis externa, often causes osteomyelitis of the external auditory canal and extensive progressive necrosis, can lead to osteomyelitis of the temporal bone and skull, and can be complicated by multiple nerve palsies, mostly facial nerve palsy, which can be life-threatening, so it is also called malignant external otitis, but it is not actually a malignant tumor. The disease often causes severe stabbing pain accompanied by otorrhea, and has a long course of disease. Most patients are older adults and patients with diabetes, and the pathogen is often Pseudomonas aeruginosa. In severe patients, the infection can invade the infratemporal fossa and spread to the subarachnoid space, causing meningitis, brain abscess, encephalomalacia, thereby leading to death.
Treatment
Antibiotics can be used to control infection. Sedatives and analgesics can be administered. In the early stage, local hot compression or ultra-shortwave diathermy can be applied
In patients without local suppuration, 1% - 3% phenol glycerin or 10% ichthyol glycerin ear drops and be used, or gauze soaked in the above-mentioned medications can be used to dress the affected area, and the frequency of dressing changes is twice a day.
After the furuncle matures, the furuncle should be punctured or incised for drainage. 3% hydrogen peroxide solution can be used to clean the pus and secretions in the external auditory canal.
In chronic patients, topical cream, paste, or ointment of antibiotics and glucocorticoids such as prednisolone and dexamethasone can be applied locally.
Infected lesions such as suppurative otitis media should be properly treated, granulation tissue should be debrided, and systemic diseases such as diabetes should be diagnosed and treated.
For suspected necrotizing external otitis, bacterial culture and antibiotic sensitivity test should be performed as soon as possible, sensitive antibiotics should be administered as early as possible, and poor systemic condition should be corrected.