Otomycosis, also known as fungal otitis externa mycotica, is an inflammatory lesion of the external auditory canal caused by a fungus that invades the external auditory canal or a conditionally pathogenic fungus in the external auditory canal and multiplies under the right conditions.
Etiology
There is a wide variety of fungi in nature, especially in tropical and subtropical areas with high temperatures and humidity, where they multiply more rapidly.
Some fungi invade the external auditory canal and can be the causative factor of external auditory canal fungal disease in the following cases.
1. In normal people, the external auditory canal is in a slightly acidic environment. If water is introduced into the ear or improper medication is used, the pH value of the external auditory canal is changed, which is conducive to the breeding of fungi.
2. Inflammation of the external ear canal caused by swimming and ear digging, immersion of pus from otitis media, accumulation and stimulation of secretions from the external ear canal enable fungi to breed and multiply. Most of the patients contacted by our department are infected by ear picking in bathing centers or barber stores, which is related to the sharing of ear picking and pedicure tools by many people and lax disinfection.
3. Chronic systemic diseases, decreased body resistance, or long-term application of antibiotics in large doses all provide conditions for fungal breeding.
4.Incorrect use and abuse of antibiotics in recent years have also increased the chance of fungal infection.
The common pathogenic fungi of external auditory canal fungal disease are yeast, Candida, bacterium, Aspergillus, Trichoderma, Actinomyces, Penicillium, etc. A group of data from CADIS reported that in 40 cases of fungal otitis externa, Candida proximalis accounted for 42.9% and Aspergillus niger for 35.7%, and 40% of the people had used antibiotics before the onset of the disease.
Pathology
Different types of fungal infections cause different local histopathological changes. For example, Aspergillus infection usually does not invade the bone, no tissue destruction. Candida albicans infection is predominantly exudative in the early stage and granulomatous inflammation in the late stage. Aspergillus and Actinomyces are septic and granulomatous changes. Trichoderma invades blood vessels, causing thrombosis, tissue infarction, causing necrosis and leukocyte infiltration.
Symptoms
Fungal infection of the external auditory canal can sometimes be asymptomatic, and its common symptoms mainly include
1. Discomfort, swelling and pain or strange itching in the external ear canal.
2. As the fungus proliferates, it can block the outer ear canal and cause a feeling of obstruction.
3.The fungal masses can irritate the outer ear canal, and there can be a small amount of secretion, and the patient feels that the outer ear canal is moist.
4. If the outer ear canal is blocked and the tympanic membrane is invaded, the patient may have hearing impairment, tinnitus, or even vertigo.
5.If the lesion damage is large or deep, there may be local pain.
6.Some fungus-induced changes are dominated by septicemia and granuloma. Severe cases can cause facial paralysis.
7.Fungi can cause necrotizing otitis externa.
8.Some fungal infections can cause generalized low to moderate fever.
Examination
Different types of fungal infections can cause different external auditory canal manifestations.
Candida infections have flushed and eroded skin with clear boundaries and white or creamy deposits on the surface of the external ear canal.
Aspergillus or yeast infections have mycelium in the external auditory canal, which can be white, grayish-yellow, gray or brown in color. Bacillus infection is initially seen as scattered papules or small pustules on the skin of the external auditory canal, which later develop into shallow ulcers with dark red edges, with granulation growth and purulent discharge on the surface.
Trichophyton infection ear pus, such as causing facial paralysis can be seen in various manifestations of facial paralysis.
Smear of secretion, fungal culture, can help determine the type of causative organism, if necessary, biopsy is needed to help differential diagnosis and treatment.
Hearing examination can tell the extent of its effect on hearing.
Diagnosis and Differential Diagnosis
Some fungal infections of the external auditory canal can be determined by examination based on what is seen in the external auditory canal. A fungal culture or smear should be done to find out the type of fungus that is infecting the ear. In some cases, a biopsy is required to make the diagnosis. It should be differentiated from common bacterial infections of the external ear canal, necrotizing otitis externa, and new organisms of the external ear canal. Sometimes it is also distinguished from infections of the middle ear.
Treatment
The main treatment is localized. Remove dirt from the external auditory canal and keep it dry. Apply broad-spectrum antifungal drugs topically, and select sensitive antifungal drugs as soon as possible after obtaining fungal culture results. In severe cases, oral antifungal medication should be given.
At present, our department adopts endoscopy to clean up the fungal mass and debridement in the external ear canal (this step is very crucial, which is the basis of fungal growth, just like plants and mudslides), especially in the anterior lower corner of the external ear canal, which can only be clearly seen and cleaned up under the endoscope. After cleaning, we inject a special anti-inflammatory and antifungal ointment and apply it evenly.
95% of patients can be cured in one treatment, without injections or medication, and the outer ear canal will return to normal after a week’s review, and a simple cleaning and application of medication will prevent recurrence. This treatment is one of the characteristic treatments of our department, which has the characteristics of no pain, low cost, short time, remarkable effect, no recurrence, and clear visibility of the treatment process, and has been praised by patients and peers.
Prevention
1.Prohibit water in the ear and improper dropping of medicine, which makes the ear moist and easy for fungus to grow.
2. Do not eat seafood and drink alcohol.
3.Avoid unclean ear harvesting.
4. Standardize treatment and avoid prolonged use of in-ear antibiotics and hormones.