Otitis externa - Causes, Symptoms and Treatments

Also known as external otitis and swimmer's ear, otitis externa is an inflammation of the skin of the external ear canal and auricle. It may be acute, chronic, or invasive and it is most common in the summer among children and young adults. With treatment, acute otitis externa usually subsides within 7 days (although it may become chronic) and tends to recur. Malignant otitis extern a is potentially life threatening and most commonly occurs in controlled diabetic patients. It is caused by Pseudomonas aeruginosa and slowly invades from the external canal into adjacent soft tissues, mastoid, and temporal bone. It may spread across the base of the skull.

Causes of Otitis externa:

Otitis externa usually results from bacterial infection with an organism, such as Pseudomonas, Proteus vulgaris, streptococci, or Staphylococcus aureus; sometimes it stems from a fungus, such as Aspergillus niger or Candida albicans (fungal otitis externa is most common in the tropics). Occasionally, chronic otitis externa results from dermatologic conditions, such as seborrhea or psoriasis. Predisposing factors include swimming in contaminated water; cleaning the ear canal with a cotton swab, bobby pin, finger, or other foreign object; exposure to dust, hair care products, or other irritants; regular use of earphones, earplugs, or earmuffs; and chronic drainage from a perforated tympanic membrane.

Signs and symptoms of Otitis externa:

Acute otitis externa characteristically produces moderate to severe pain that is exacerbated by manipulation of the auricle or tragus, clenching the teeth, opening the mouth, or chewing. The canal appears red and swollen. Its other clinical effects may include fever, foul-smelling aural discharge, regional cellulitis, and partial hearing loss.

Fungal otitis externa may be asymptomatic, although A. niger produces a black or gray blotting paper-like growth in the ear canal. In chronic otitis externa, pruritus replaces pain, which may lead to scaling and skin thickening with a resultant narrowing of the lumen. An aural discharge may also occur. Asteatosis (lack of cerumen) is common.

Diagnosis for Otitis externa:

Physical examination confirms otitis externa. In acute otitis extern a, otoscopy reveals a swollen external ear canal (sometimes to the point of complete closure), periauricular lymphadenopathy (tender nodes in front of the tragus, behind the ear, or in the upper neck) and, occasionally, regional cellulitis.

In fungal otitis externa, removal of growth shows thick red epithelium. Microscopic examination or culture and sensitivity tests can identify the causative organism and determine antibiotic treatment. Pain on palpation of" Ihe tragus or auricle distinguishes acute otitis extern a from otitis media.

In chronic otitis externa, physical examination shows thick red epithelium in the ear canal. Severe chronic otitis externa may reflect underlying diabetes mellitus, hypothyroidism, or nephritis. Other conditions to consider are the presence of a foreign body in the ear canal, pruritus, malignant otitis externa, and squamous cell carcinoma of the external ear.

Treatment of Otitis externa:Otitis externa

Treatment varies, depending on the type of otitis externa. To relieve the pain of acute otitis externa, treatment includes heat therapy to the periauricular region (heat lamp; hot, damp compresses; heating pad), aspirin or acetaminophen, and codeine. Instillation of antibiotic eardrops such as polymyxin (with or without hydrocortisone) follows cleaning of the ear with alcoholacetic acid mixtures and removal of debris. If fever persists or regional cellulitis develops, a systemic antibiotic is necessary.

As with other forms of this disorder, fungal otitis externa necessitates careful cleaning of the ear. Application of a keratolytic or 2% salicylic acid in cream containing nystatin may help treat otitis extern a resulting from candidal organisms.

Instillation of slightly acidic eardrops creates an unfavorable environment in the ear canal for most fungi as well as Pseudomonas.

Primary treatment of chronic olitis externa consists of cleaning the car and removing debris. Supplemental therapy includes instillation of antibiotic eardrops or application of antibiotic ointment or cream (neomycin, bacitracin, or polymyxin, possibly combined with hydrocortisone). Another ointment contains phenol, salicylic acid, precipitated sulfur, and petrolatum, and produces exfoliative and anti pruritic effects.

For mild chronic otitis externa, treatment may include instilling antibiotic eardrops once or twice weekly and wearing specially fitted earplugs while showering, shampooing, or swimming.

Special considerations and Prevention tips of Otitis externa:

If the patient has acute otitis externa:

1. Monitor vital signs, particularly temperature. Watch for and record the type and amount of aural drainage.

2. Remove debris and gently clean the ear canal with mild Burow's solution (aluminum acetate). Place a wisp of cotton soaked with solution into the ear, and apply a saturated compress directly to the auricle. Afterward, dry the ear gently but thoroughly. (In severe otitis externa, cleaning may be delayed until after initial treatment with antibiotic eardrops.)

3. To instill eardrops in an adult, pull the pinna upward and backward to straighten the canal. For children, pull the pinna downward and backward. To ensure that the drops reach the epithelium, insert a wisp of cotton moistened with eardrops.

4. If the patient has chronic otitis externa, clean the ear thoroughly. Use wet soaks intermittently on oozing or infected skin. If the patient has a chronic fungal infection, clean the ear canal well, then apply an exfoliative ointment.

To prevent otitis externa, suggest using lamb's wool emplugs coated with petrolatum to keep water out of the ears when showering or shampooing. Also, tell the patient to wear earplugs or to keep his head above water when swimming and to instill two or three drops of 3% boric acid solution in 70% alcohol before and after swimming to toughen the skin of the external car canal. Warn the patient against cleaning the ears with cotton swabs or other objects and urge prompt treatment of otitis media to prevent perforation of the tympanic membrane. If the patient is diabetic, evaluate him for malignant otitis extema. Hearing aid users who are prone to otitis externa should consider having the device vented to improve aeration of the external ear canal.