What antibiotic is used to treat otitis externa (inflammation of the external ear)?

From the Guidelines

For otitis externa, the recommended first-line treatment is topical antibiotic ear drops, typically containing fluoroquinolones like ciprofloxacin or ofloxacin, often combined with steroids to reduce inflammation. A common regimen is ciprofloxacin 0.3% with dexamethasone 0.1% ear drops, 4 drops in the affected ear twice daily for 7-10 days 1. Alternatively, ofloxacin 0.3% ear drops, 5-10 drops in the affected ear twice daily for 7-10 days can be used. Before applying drops, the ear canal should be gently cleaned of debris to allow medication to reach infected tissues. Patients should avoid getting water in the ear during treatment and may need to use a cotton ball lightly coated with petroleum jelly when showering.

For severe cases or diabetic patients, oral antibiotics like ciprofloxacin 500mg twice daily for 7-10 days may be necessary 1. It is essential to consider the patient's medical history, including diabetes, HIV infection, or other immunocompromised states, as these conditions may require special consideration and modification of treatment. In patients with diabetes or immunocompromised states, systemic antibiotics may be necessary in addition to topical therapy, and ear canal irrigation should be avoided to prevent necrotizing otitis externa 1.

Key considerations in the management of otitis externa include:

• Accurate diagnosis and differential diagnosis to rule out other conditions such as otomycosis or necrotizing otitis externa
• Use of topical antibiotic ear drops as first-line treatment
• Consideration of patient's medical history and modification of treatment as necessary
• Avoidance of ear canal irrigation in patients with diabetes or immunocompromised states
• Use of oral antibiotics in severe cases or diabetic patients.

These treatments are effective because they directly target the bacterial infection while reducing inflammation in the ear canal, addressing both the infection and symptoms like pain and swelling 1.

From the FDA Drug Label

Ciprofloxacin otic solution, 0.2% is a quinolone antimicrobial indicated for the treatment of acute otitis externa due to susceptible isolates of Pseudomonas aeruginosa or Staphylococcus aureus. The recommended antibiotic for otitis externa is ciprofloxacin (OTIC), specifically ciprofloxacin otic solution, 0.2%, which is indicated for the treatment of acute otitis externa due to susceptible isolates of Pseudomonas aeruginosa or Staphylococcus aureus 2.

• The dosage is twice daily (approximately 12 hours apart) for 7 days.
• It is essential to note that ciprofloxacin otic solution, 0.2% is for otic use only and should not be used for injection, inhalation, or topical ophthalmic use.
• The most common adverse reactions reported were application site pain, ear pruritus, fungal ear superinfection, and headache 2.

From the Research

Antibiotic Treatment for Otitis Externa

• The use of topical antibiotics such as ofloxacin otic solution has been shown to be effective in the treatment of otitis externa, with a cure rate of 91% among clinically evaluable patients 3.
• Other antibiotics such as ciprofloxacin and tobramycin have also been found to be effective in treating otitis externa, with cure rates of 77% and 56% respectively 4.
• A study comparing the efficacy and safety of ciprofloxacin/dexamethasone with neomycin/polymyxin B/hydrocortisone found that ciprofloxacin/dexamethasone was clinically and microbiologically superior in the treatment of mild to severe otitis externa 5.
• However, another study suggests that topical antibiotics may not be necessary in the management of otitis externa, as a group of patients receiving drops without an aminoglycoside antibiotic showed similar clinical response to those receiving the antibiotic preparation 6.

Commonly Used Antibiotics

• Ofloxacin otic solution: effective in treating otitis externa with a cure rate of 91% 3.
• Ciprofloxacin: effective in treating otitis externa with a cure rate of 77% 4.
• Tobramycin: effective in treating otitis externa with a cure rate of 56% 4.
• Neomycin/polymyxin B/hydrocortisone: less effective than ciprofloxacin/dexamethasone in treating otitis externa 5.

Microbiologic Eradication

• The use of ofloxacin otic solution has been shown to have an eradication rate of 96% for potentially pathogenic strains, including Pseudomonas aeruginosa and Staphylococcus aureus 3.
• Ciprofloxacin/dexamethasone has also been found to have a high microbiologic eradication rate of 94.7% 5.