From the Guidelines
Acetic acid is a viable treatment option for fungal otitis externa, but its superiority over other treatments is not established. For fungal ear infections, 2% acetic acid solutions can be applied as 3-5 drops in the affected ear 3-4 times daily for 7-14 days, creating an acidic environment that inhibits fungal growth and helps restore the ear canal's natural acidic pH 1. The effectiveness of acetic acid is supported by guidelines that suggest topical therapy with irrigating solutions of boric acid, acetic acid, or azole cream may be effective in eradicating Aspergillus otomycosis 1. However, other antifungal preparations like clotrimazole 1% solution or nystatin suspensions are equally effective and sometimes preferred.
Key considerations for treatment include:
- Cleaning the ear canal of debris before application
- Continuing treatment for at least 7 days after symptoms resolve to prevent recurrence
- Potential combination treatments with steroids or antibiotics in cases with significant inflammation or suspected bacterial co-infection
- Advising patients to keep the ear dry during treatment and avoid cotton swabs which can push debris deeper into the canal. In refractory cases or contexts of perforated tympanic membranes, use of voriconazole, posaconazole, or itraconazole may be appropriate 1.
From the FDA Drug Label
CLINICAL PHARMACOLOGY Acetic acid is anti-bacterial and anti-fungal; propylene glycol is hydrophilic and provides a low surface tension; benzethonium chloride is a surface active agent that promotes contact of the solution with tissues. The information provided indicates that acetic acid has anti-fungal properties. However, it does not directly compare the effectiveness of acetic acid to other treatments for fungal otitis externa, nor does it state that acetic acid is superior for this condition. Therefore, based on the provided drug label, it cannot be concluded that acetic acid is superior for treating fungal otitis externa 2.
From the Research
Treatment of Fungal Otitis Externa
- The use of acetic acid in treating fungal otitis externa has been studied, with some evidence suggesting its effectiveness 3, 4.
- A study from 2001 found that acidification with a topical solution of 2 percent acetic acid combined with hydrocortisone for inflammation is effective treatment in most cases of otitis externa 3.
- Another study from 2022 used acetic acid 2% solution for ear canal debridement and irrigation before treating patients with sertaconazole, miconazole, or clotrimazole creams, showing significant differences in response to treatment compared to the placebo group 4.
Comparison with Other Treatments
- Topical antifungals, such as clotrimazole, miconazole, bifonazole, ciclopiroxolamine, and tolnaftate, are potentially safe choices for the treatment of otomycosis, especially in patients with a perforated eardrum 5.
- The oral triazole drugs, itraconazole, voriconazole, and posaconazole, are effective against Candida and Aspergillus, with good penetration of bone and the central nervous system 5.
- A systematic review from 2015 evaluated the effects of empirical treatments for otitis externa, including topical acetic acid, topical aluminium acetate, topical antibacterials, topical antifungals, and topical corticosteroids 6.
Efficacy of Acetic Acid
- While acetic acid has been shown to be effective in treating otitis externa, its superiority over other treatments for fungal otitis externa is not clearly established 3, 4.
- The 2022 study found that sertaconazole had comparable results with miconazole and clotrimazole in the treatment of otomycosis, with acetic acid used as a preliminary treatment 4.