Ear Infection – Diagnosis, Symptoms, and Treatment

What is an Ear Infection?

An ear infection is a 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 referred to by the medical term labyrinthitis and are far less common than the other two types. 

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 underwater, 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. In rare cases, bacteria may infect this area and lead to severe symptoms. 

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 which has led to the name swimmer’s ear being used to describe otitis externa.  The infection leads to inflammation, pain, and swelling of the outer ear canal; often resulting in the production of pus. In severe cases, the canal can completely close off due to swelling and discharge.

Otitis media (middle ear infections) are typically caused by the translocation of bacteria from the nasopharynx into the middle ear.  This most often occurs in children as their more compact ear, nose, and throat anatomy predispose them to middle ear infection.  Patients typically experience pain, a sensation of pressure, 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. The organs that are responsible for the sensation of sound are also located here, but are not affected by most infections. This is usually caused by viruses similar to the ones that are responsible for the common cold.

How Common is an Ear Infection?

Ear infections are extremely common in the United States. Middle ear infections are the most common, nearly 80% of children are expected to have at least one episode of otitis media within their first two years of life. In many children, otitis media is recurrent and will present several times in a year. This is more common in children with seasonal allergies or suppressed immune systems. 

Approximately 10% of individuals develop otitis externa 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 otitis externa.  Symptoms are more common during the summer compared to winter – as this condition is related to outdoor water activities (eg, swimming). Severe otitis externa can occur in some individuals that have suppressed immune systems. 

Signs and Symptoms

Symptoms and signs often depend on which area of the ear is infected, some of these conditions have symptoms that overlap but a diagnosis can generally be made with careful examination. 

Outer ear infections (otitis externa) usually present with:

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

Middle ear infections 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 abnormal movements of the eyes known as nystagmus and difficulty walking, referred to as gait instability, on examination.

Outer ear infections are generally the most painful and are the only ones that present with discharge from the ear. Middle ear infections commonly result in a sense of pressure and are the most likely to cause decreased hearing. And inner ear infections generally present with symptoms related to balance. 

Diagnosis

The diagnosis of an ear infection can generally be made with only a history and physical exam. The otoscopic examination is the main physical exam maneuver used in diagnosing an ear infection. By looking at the ear canal and the eardrum your physician can determine if an external or middle ear infection is present. 

Your doctor will occasionally need to obtain laboratory and imaging studies to confirm the diagnosis.  This usually occurs if your symptoms have not resolved after some time, are unresponsive to antibiotics, 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 as severe outer ear infections ar more common in diabetic patients.

If there is any pus in the outer ear canal, your doctor will likely send a sample to the laboratory for gram stain and culture – this will guide antibiotic therapy, ensuring that the most effective antibiotic is chosen.

Your doctor may recommend a CT scan or MRI of the head if your symptoms reoccur regularly or are severe. This is used to evaluate for any complications of repeated ear infections or search for any 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 generally perform a regular ear canal lavage with saline to remove any pus or debris.  These debris slow healing and promote bacterial growth. In addition to lavage, your doctor will likely prescribe antibiotic ear-drops or a combination antibiotic and steroid.  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 oral antibiotics such as Moxatag (amoxicillin), Zithromax (azithromycin), and Augmentin (amoxicillin-clavulanate). Many of these infections are caused by viruses and will not respond to antibiotics. 

Labyrinthitis has no specific treatment.  Vestibular suppressants are medications that reduce the sensation of dizziness and include antihistamines and antiemetics. These are typically prescribed to reduce the most severe symptoms felt within the first few days of the disease.  Common antihistamines include Benadryl (diphenhydramine) and Antivert (meclizine).  Frequently prescribed antiemetics consist of Reglan (metoclopramide) and Zofran (ondansetron).

References:

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