Ear Infection

Ear Infection

What is an Ear Infection?

Ear infections refer to viral, bacterial, or fungal infection of the outer, middle, or inner ear.  Infection of the outer ear is called otitis externa, whereas infection of the middle ear is referred to as otitis media.  Inner ear infections are medically termed labyrinthitis.

The epidemiology and symptoms vary depending on the anatomic location infected.  For instance, middle ear infections (otitis media) frequently occur in children and less commonly affect adults.  These infections tend to be associated with fever and bulging of the eardrum (tympanic membrane).

Otitis externa (outer ear infection) is often referred to as swimmer’s ear because it frequently affects people who submerge their heads under water, leading to pseudomonas infection.  This type of infection causes ear pain and swelling of the outer ear with discharge.  Sometimes, the ear canal is completely closed off.  Labyrinthitis is typically caused by viruses and accompanied by upper respiratory symptoms.  Patients often develop dizziness or disequilibrium due to inflammation of the semicircular canals in the inner ear.

What Causes an Ear Infection?

They are caused by either viruses, bacteria, or fungi, which invade different anatomic compartments of the ear.  Otitis externa is typically caused by bacterial (eg, pseudomonas) or fungal infections of the outer ear.  This frequently occurs in patients who regularly swim (swimmer’s ear).  Infection leads to inflammation, pain, and swelling of the outer ear canal – this results in pus formation in the outer ear canal.  In severe cases, the canal can completely close off due to swelling and discharge, which often requires the placement of a wick to administer treatment.

Otitis media (middle ear infections) are typically caused by translocation of bacteria from the nasopharynx into the middle ear.  This most often occurs in children as their ear, nose, and throat anatomy predisposes them to middle ear infection.  Patients typically have pain and decreased hearing in the affected ear, as well as fever.

Labrinynthitis is infection/inflammation of the inner ear.  The inner ear is composed of semicircular canals that are responsible for balance and stability.  This is usually caused by the same viruses responsible for the common cold.

How Common is an Ear Infection?

They are exceedingly common in the United States and responsible for frequent primary care visits.  Severe or complicated cases often require referral to an ear, nose, and throat specialist.

Approximately 10% of individuals develop external otitis during their lifetime.  The condition affects all ages; however, children are more frequently affected than adults.  An estimated 19% of children age 5-9 are evaluated in the primary care clinic each year for external otitis.  Symptoms are more common during the summer compared to winter – this is often related to outdoor water activities (eg, swimming).

Otitis media is also more commonly seen in children compared to adults.  About 80% of children age <2 have one or more episodes of otitis media each year in the United States.  Boys are more often affected than girls.

Signs and Symptoms

Symptoms and signs often depend on the anatomic compartment of the ear that is affected.  Some of the features of ear infection overlap between compartments.

Outer ear infections (otitis externa) occur in swimmers and usually cause:

  • Ear pain
  • Discharge
  • Decreased hearing
  • Swelling of the outer ear canal
  • Tenderness during palpation over the tragus

Middle ear infections occur in children and typically present with:

  • Fever
  • Ear pain
  • Decreased hearing
  • Bulging tympanic membrane on otoscopic examination

Inner ear infections (labyrinthitis) may not have external examination findings – the ear canal and tympanic membrane often appear normal.  However, patients may have nystagmus and gait instability on examination.


Your doctor will occasionally need to obtain laboratory and imaging studies to confirm the diagnosis.  This usually occurs if you have not responded to first-line therapy or your case is atypical in nature.  Some commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and inflammatory markers (ESR/CRP).  They will also usually screen you for diabetes.

If there is any gross pus in the outer ear canal, your doctor will likely send a sample to the laboratory for gram stain and culture – this will guide antibacterial therapy.

Your doctor may recommend a CT scan or MRI of the head to evaluate for any complications of ear infection or structural abnormalities that could help explain your symptoms.

Ear Infection Medication and Treatment

The treatment depends on the anatomic compartment that is infected.  Patients with otitis externa should have ear canal lavage with saline to remove any pus or debris.  This debris prevents healing and promotes bacterial growth.  Your doctor with likely prescribe a topical antibiotic alone or in combination with a topical corticosteroid.  Combination therapy typically includes Cortisporin (hydrocortisone and neomycin-polymyxin B) or Ciprodex Ear Drops (ciprofloxacin-dexamethasone).

Middle ear infections (otitis media) are typically treated with antibiotics such as Moxatag (amoxicillin), Zithromax (azithromycin), and Augmentin (amoxicillin-clavulanate).

Labyrinthitis has no specific treatment.  Vestibular suppressants such as antihistamines and antiemetics are typically prescribed to reduced symptoms within the first 2 days.  Common antihistamines include Benadryl (diphenhydramine) and Antivert (meclizine).  Frequently prescribed antiemetics consist of Reglan (metoclopramide) and Zofran (ondansetron).


  1. Schwartz LE, Brown RB. Purulent otitis media in adults. Arch Intern Med 1992; 152:2301. - https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/616798
  2. Leskinen K, Jero J. Acute complications of otitis media in adults. Clin Otolaryngol 2005; 30:511. - https://www.ncbi.nlm.nih.gov/pubmed/16402975
  3. Kaushik V, Malik T, Saeed SR. Interventions for acute otitis externa. Cochrane Database Syst Rev 2010; :CD004740. - https://www.ncbi.nlm.nih.gov/pubmed/20091565




Ear Infection Medicine

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.