Ear Infection (Otitis Externa)

EAR INFECTION:

• 1.Otitis Externa (Swimmer’s ear)
• 2.Otitis Media
  • a) Acute Otitis Media
  • b) Chronic Otitis Media
• 3.Labyrinthitis

1.OTITIS EXTERNA:

^Cause inflammation (redness and swelling) of the external ear canal(EAC), which is the tube between the outer ear and eardrum. 

^Called as swimmer’s ear as repeated exposure to water can make ear canal more vulnerable to inflammation.

Symptoms:

• ^Ear pain, can be severe. (Otalgia)
• ^itchiness in the ear canal (Pruritus) 
• ^a discharge of liquid or pus from the ear (Otorrhea)
• ^some degree of temporary hearing loss
• ^tenderness to palpation 
• ^usually one ear is affected 

Causes:

• ^bacterial infection (most common) (Pseudomonas aeruginosa and Staphylococcus aureus).
• ^irritation.
• ^fungal infections (Otomycosis) (Aspergillus, Candida).
• ^allergies.
• ^damaging skin inside your ear (due to cotton wool buds)
• ^regularly getting water in your ear (ideal environment for bacteria to grow).

Prevention:
^Instruct Patient to not use cotton swabs or any other objects to canal.

^Swimmers are to be instructed to use ear plugs and advised to use alcohol-vinegar (1:1) drops after swimming.

Ix:

^Otoscopy (reveals mycelia establishing diagnosis of Otomycosis)

^Lab: typically not needed, gram staining and culture of auditory canal can help in patients with immunocompromised status.

Cx:

• ^Abscess
• ^Stenosis of ear canal (due to thick and dry skin build inside ear canal due to chronic OE)
• ^Inflamed or perforated eardrum (spread of infection to ear drum causing tear and symptoms such as: temporary hearing loss, earache or discomfort, a discharge of mucus from ear, ringing or buzzing in your:tinnitus) 
• ^Malignant otitis external, infection spreads from the ear canal into the surrounding bone, requires prompt treatment with antibiotics and sometimes surgery, can be fatal if left untreated.

Rx:

• ^sometimes can self-resolve, but takes several weeks
• ^NSAID, Opioids or topical steroid preparations (for pain)
• ^Antibiotic drops (Ofloxacin, Ciprofloxacin, Colistin, Polymyxin B, Neomycin, Chloramphenicol, Gentamicin and Tobramycin.)
• ^Polymyxin B and Neomycin preparations are often used in combination for the treatment of S Aureus and P Aeroginosa Infections.
• ^Steroid ear drops helps reduce edema and otalgia
• ^Otomycosis Rx includes cleansing and debriding the EAC, acidifying the canal, and administering anti fungal agents.
• ^Non specific Antifungal (Merthiolate)
• ^Specific anti fungal (clotrimazole, Nystatin, Ketoconazole)
• ^Itraconazole is orally administered, effective against Aspergillus.
• ^Aural packing (Ear wick placement) and Antibiotic/combination preparation application – 4 times a day like 3-4 drops, changed every day.

Treatment Guidelines:

1. Acute otitis externa should be distinguished from other possible causes of ear canal inflammation.
2. Topical antimicrobial otic preparations should be considered the first-line treatment for uncomplicated acute otitis externa.
3. Addition of a topical corticosteroid may result in faster resolution of symptoms such as pain, canal edema, and canal erythema.
4. Systemic antibiotics should be used only if the infection has spread beyond the ear canal or in patients at high risk of such spread.
5. Use of aural toilet should be considered to remove debris from the ear canal before treatment.

Dosage:

Common Antimicrobial Otic Preparations for OE:

1. Acetic acid 2% (Vosol)  4-6 times daily. (May cause pain and irritation; may be less effective than other treatments if use is required beyond one week; often used as prophylactic agent).
2. Ciprofloxacin 0.3%/dexamethasone 0.1% (Ciprodex) twice daily. Low risk of sensitization.
3. Hydrocortisone 2%/acetic acid 1% (Vosol HC) 4-6 times daily; may cause pain and irritation. 
4. Neomycin/Polymyxin B/hydrocortisone, solution or suspension: 3-4 times daily; Ototoxic; higher risk of contact hypersensitivity; avoid in chronic/eczematous otitis externa.
5. Ofloxacin 0.3%; Once to twice daily; Low risk of sensitisation.

NECROTIZING (MALIGNANT) EXTERNAL OTITIS (NEO):

^Lethal infection of EAC and surrounding structures.

Cause:

^Pseudomonas Aeruginosa (common)

Risk Factors:

• ^Diabetes Mellitus
• ^Elderly
• ^Immunocompromised state
• ^Human Immunodeficiency Virus (HIV)

Symptoms:

• ^Severe, unrelenting Ear pain & Headache
• ^Persistent discharge
• ^Does not respond to topical medications
• ^Commonly associated with DM
• ^Granulation tissue in posterior and inferior canal.
• ^Extra-auricular findings:
  • 1.Cervical lymphadenopathy
  • 2.Trismus (TMJ involvement)
  • 3.Facial nerve palsy (Bell’s)

Dx:
^Lab: FBC, Culture of Discharge, ESR, Serum glucose, Serum Creatinine.

^Radio: CT or MRI (ear), Tc 99m medronate methylene bone scanning, Ga 65 scintigraphy.

Prevention:

• ^Avoid use of cotton swabs in ear and other canal trauma/
• ^Use caution when irrigating ear of high risk patients.
• ^Treat eczema of ear canal and other pruritic dermatitis.

Rx:

• ^IV Antibiotics for 4 weeks – with serial gallium scans monthly.
• ^Local canal debridement until healed.
• ^Pain control
• ^Use of topical agents controversial
• ^Hyperbaric oxygen experimental
• ^Surgical debridement for refractory cases.
• ^Mastoidectomy with facial Nerve decompression / subtotal petrosectomy.

Case study (Efficacy of Ciprofloxacin 0.2%):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150478/