Patient will present as → a 4-year-old girl who is brought to the clinic by her mother, who states that the child has been complaining of progressively worsening ear pain and itchiness over the past week. Examination reveals left tragal tenderness and an edematous and closed canal. Weber lateralizes to the left.
Otitis externa (aka swimmer's ear) is an infection of the external auditory canal secondary to trauma or a consistently moist environment, which favors the growth of fungi or bacteria
- It generally presents with canal itching and pain with movement of the ear. If the canal is closed, Weber is expected to lateralize to the side of the blocked canal
- Painful edema with cheesy white discharge, sometimes it is impossible to see the TM
- Most common causes: Pseudomonas aeruginosa (38%), S. epidermidis (9 percent), and Staphylococcus aureus (8 percent)
- Malignant otitis externa is commonly seen in diabetics
- Fungal OM is responsible for approximately 9 percent of ear canal infections. Aspergillus niger (90%) and Candida are the most common organisms
Diagnosis is clinical by otoscopy
Otitis externa (“swimmer’s ear”) with inflammation and narrowing of the external auditory canal. Photo by James Heilman, MD via Wikimedia Commons, CC BY 3.0.
Bacterial otitis externa:
- If perforated or chance of perforation: Ciprofloxacin 0.3% and dexamethasone 0.1% suspension: 4 drops BID × 7 days or ofloxacin: 0.3% solution 10 drops once a day × 7 days
- Cortisporin otic SUSPENSION, which is less irritating than the solution
Fungal otitis externa
- Topical therapy, anti-yeast for Candida or yeast: 2% acetic acid 3–4 drops QID; clotrimazole 1% solution; itraconazole oral
Treatment Algorithm for Otitis Externa (OE)
- Step 1: Can the tympanic membrane (TM) be visualized and is it intact?
→ Yes: Use neomycin/polymyxin B/hydrocortisone otic suspension
→ No or TM is perforated/tubes present: Use ofloxacin or ciprofloxacin otic or ophthalmic drops (non-ototoxic and sterile) - Step 2: Is cost a concern and TM is intact?
→ Yes: Consider gentamicin or tobramycin ophthalmic drops (low-cost alternative, only if TM is intact)
→ No: Use Ciprodex (ciprofloxacin/dexamethasone) for faster symptom relief - Step 3: Is the canal too swollen for drop entry?
→ Yes: Insert wick to facilitate medication delivery
→ No: Proceed with drop instillation - Step 4: Pain management
→ Use oral acetaminophen or ibuprofen
→ Avoid topical analgesics - Step 5: Prevent recurrence
→ Recommend drying ears after water exposure (hairdryer or 1:1 vinegar-alcohol mix)
Question 1 |
A 23-year-old woman presents to the clinic with ear pain and itching in her right ear that began three days ago. She mentions that she recently returned from a beach vacation, where she spent a lot of time swimming. On physical examination, the external ear canal appears erythematous and swollen, with some purulent discharge. The tympanic membrane is intact. Which of the following is the most common etiological factor for her condition?
Staphylococcus aureus Hint: While S. aureus can cause otitis externa, it is less common than Pseudomonas aeruginosa. S. aureus is more commonly associated with skin infections, such as impetigo or folliculitis. | |
Pseudomonas aeruginosa | |
Candida albicans Hint: Candida albicans is a yeast that can cause fungal otitis externa, particularly in individuals with immunocompromised states or those using hearing aids. However, fungal infections are less common than bacterial infections. | |
Streptococcus pneumoniae Hint: Streptococcus pneumoniae is a common cause of otitis media, not otitis externa. It is associated with middle ear infections rather than infections of the external ear canal. | |
Aspergillus niger Hint: Aspergillus niger is another fungal cause of otitis externa but is much less common than Pseudomonas aeruginosa. It typically occurs in immunocompromised individuals or those with chronic otitis externa. |
Question 1 Explanation:
Pseudomonas aeruginosa is the most common etiological agent of otitis externa, particularly in individuals with a history of swimming, which creates a moist environment conducive to bacterial growth. This condition, often referred to as "swimmer's ear," occurs when water remains in the ear canal, facilitating bacterial growth and leading to infection.
Question 2 |
A 42-year-old woman presents to the clinic with severe left ear pain, hearing loss, and purulent discharge from the ear for the past two days. She reports that the pain started about a week ago after she went swimming in a lake, and it progressively worsened. She now feels a "popping" sensation in her ear followed by increased drainage. Physical examination reveals a swollen and erythematous external ear canal with a purulent discharge. The tympanic membrane (TM) is difficult to visualize due to the swelling, but there is a suspicion of a possible rupture based on the patient's history and symptoms. Which of the following is the most appropriate treatment option?
Oral amoxicillin Hint: Amoxicillin is typically used for otitis media, not otitis externa. Moreover, it is not the first-line treatment for otitis externa, particularly when Pseudomonas aeruginosa, a common pathogen in otitis externa, is suspected. | |
Topical ofloxacin ear drops | |
Topical neomycin/polymyxin B/hydrocortisone ear drops Hint: These drops are generally effective for otitis externa, but they are contraindicated in the presence of a perforated tympanic membrane because neomycin is ototoxic and could potentially cause hearing loss if it enters the middle ear through the perforation. | |
Topical acetic acid solution Hint: Acetic acid can be used in cases of mild otitis externa to restore the normal acidic environment of the ear canal, but it is not effective for treating an infection with a suspected ruptured tympanic membrane and should be avoided in such cases due to the risk of ototoxicity. | |
Oral ciprofloxacin Hint: While ciprofloxacin is effective against Pseudomonas aeruginosa, systemic antibiotics are generally not needed for uncomplicated otitis externa unless there is systemic involvement, significant surrounding tissue infection, or the patient is immunocompromised. |
Question 2 Explanation:
Topical ofloxacin ear drops are the most appropriate treatment for otitis externa with a possible ruptured tympanic membrane. Ofloxacin is a fluoroquinolone antibiotic that is safe for use in cases where the tympanic membrane might be ruptured because it is non-ototoxic and effective against common pathogens such as Pseudomonas aeruginosa. The treatment addresses the infection while minimizing the risk of ototoxicity that could occur if the ear drops reach the middle ear through the perforation.
Question 3 |
A 54-year-old type 2 diabetic male presents for follow-up evaluation of previously diagnosed persistent otitis externa. Early in the disease process, a CT scan was obtained secondary to non-improvement on antibiotics. Results showed osseous erosion of the floor of the ear canal. He has been on ciprofloxacin 1000 mg twice daily for two months since the CT scan and currently has no further edema, erythema, or exudate from the external auditory canal or surrounding tissue. Which of the following is an appropriate treatment plan?
Continue prophylactic antibiotics for an additional 6 weeks Hint: See C for explanation. | |
Immediately discontinue antibiotics Hint: See C for explanation. | |
Obtain gallium scan to ensure reduction of inflammatory process | |
Skin swab culture of healthy tissue Hint: See C for explanation. |
Question 3 Explanation:
Treatment of malignant external otitis requires prolonged antipseudomonal antibiotic administration often for several months. To avoid relapse, antibiotics should be continued even in the asymptomatic patient, until gallium scanning indicates a marked reduction in the inflammatory process.
Question 4 |
A 6-year-old boy presents with fever, pain, and tenderness behind the left ear. The parents report that he had an episode of otitis media two weeks ago, which was treated with oral antibiotics. On physical examination, there is erythema, swelling, and tenderness behind the left auricle, along with auricular proptosis. A CT scan of the head reveals opacification of the mastoid air cells on the left side. Which of the following is the most appropriate management for this patient?
Oral antibiotics and observation Hint: Oral antibiotics alone are not sufficient in the treatment of mastoiditis, especially in the presence of systemic symptoms and radiographic evidence of mastoid involvement. This approach would risk further complications, including the spread of the infection. | |
High-dose intravenous antibiotics and myringotomy | |
Tympanostomy tube placement Hint: While tympanostomy tube placement may be considered in recurrent otitis media, it is not the initial treatment for acute mastoiditis. The priority in this case is to control the infection aggressively with intravenous antibiotics and possibly surgical drainage. | |
Surgical mastoidectomy Hint: Surgical mastoidectomy may be required if the infection does not respond to intravenous antibiotics and myringotomy or if there is evidence of complications such as abscess formation. However, it is not the first-line treatment and is reserved for cases where initial management fails. | |
Oral corticosteroids Hint: Oral corticosteroids are not indicated in the management of mastoiditis and could potentially worsen the infection by suppressing the immune response. The primary treatment involves controlling the infection with antibiotics and surgical intervention if necessary. |
Question 4 Explanation:
High-dose intravenous antibiotics and myringotomy is the most appropriate initial management for acute mastoiditis, especially in the presence of symptoms such as fever, pain, tenderness behind the ear, and auricular proptosis. Mastoiditis is a potential complication of otitis media, and the opacification of the mastoid air cells on CT scan indicates infection and inflammation in the mastoid process. Myringotomy allows for drainage of the middle ear, which can reduce pressure and help resolve the infection.
There are 4 questions to complete.
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References: Merck Manual · UpToDate