In otitis externa (synonyms: Acute otitis externa; Acute otitis externa due to a chemical substance; Acute actinic otitis externa; Acute eczematous otitis externa; Acute noninfectious otitis externa; Badeotitis; Cholesteatoma of the external ear; Chronic otitis externa; Eczema of the external ear; Eczematous otitis externa; Auditory canal abscess; Auditory canal eczema; Auditory canal furuncle; Auditory canal granulation; Auditory canal carbuncle; Auditory canal phlegmon; Hemorrhagic otitis externa; Infectious otitis externa; Keratitis obturans of the ear canal; Contact otitis; Necrotizing otitis externa; Ear eczema; Ear carbuncle; Ear pinna dermatitis; Ear pinna eczema; Ear pinna furuncle; Auricular carbuncle; Auricular phlegmon; Otitis externa; Otitis externa catarrhalis; Otitis externa circumscripta; Otitis externa diffusa; Otitis externa haemorrhagica; Otitis externa maligna; Otitis externa sicca; ICD-10-GM H60. -: Otitis externa) is an inflammation of the skin of the external auditory canal, often caused by microorganisms or allergies.
The most common bacterial pathogens are Pseudomonas aeruginosa (58%) and Staphylococcus aureus (18%). Other pathogens may include Proteus mirabilis (4%), Streptococcus pyogenes (2%), Escherichia coli (2%), Enterococcus sp. (2%), and Aspergillus sp. (2%).
Pseudomonas aeruginosa is found in warm water (e.g., hot tubs or swimming pools in hot regions) and is resistant to chlorine. Otitis externa is a common disease in the context of bathing vacations (“bathotitis”).
The disease occurs more frequently in hot and humid climates.
The pathogen enters the body parenterally (the pathogen does not penetrate through the intestine, but enters through the smallest injuries of the skin (percutaneous infection), caused for example by incorrect cleaning with cotton swabs).
The following forms of otitis externa can be distinguished:
- Otitis externa diffusa (eczema of the ear canal) – weeping and dry form.
- Otitis externa circumscripta (auditory canal furuncle).
- Otitis externa necroticans (malignant otitis externa) – necrotizing inflammation of the auditory canal, which spreads to the bone and cranial nerves.
Otitis externa is clustered in children, diabetics and wearers of hearing aids.
Frequency peak: the maximum incidence of otitis externa is between the ages of 7 and 12 years in children, between the ages of 45 and 54 years in women and between the ages of 65 and 74 years in men.
The lifetime prevalence (disease incidence throughout life) is 10% (in Germany).
Course and prognosis: The disease is usually painful and protracted. In 10% of cases, both external auditory canals are affected. Prompt diagnosis and specific therapy are necessary to prevent progression of acute otitis externa to the chronic or malignant form. In the course of otitis externa, the infection can spread, for example, to the surrounding soft tissue or to the eardrum. However, the disease usually heals without complications.
