A swollen ear canal is a common condition that affects approximately 10 percent of people during their lifetimes. The most common cause is a bacterial infection, but there are a few other potential causes, too.

In this article, we’ll take a closer look at what can cause your ear canal to become swollen shut and how you can treat this condition.

There are several potential causes of an ear canal that’s swollen shut, but the most common cause is a bacterial infection known as swimmer’s ear.

Let’s look at the possible causes in more detail.

Swimmer’s ear

Swimmer’s ear is a bacterial infection of your auditory canal. This is the passageway that leads from the outside of your ear to your eardrum. Swimmer’s ear can sometimes affect your external ear, too. The medical term for swimmer’s ear is otitis externa.

Older 2011 research from the CDC estimated that 2.4 million healthcare visits each year were because of swimmer’s ear. It can occur at any age, but is most common between the ages of 7 to 14 years.

Pseudomonas aeruginosa and Staphylococcus aureus are the most common bacteria that cause this infection, according to a 2015 research review.

Swimmer’s ear can develop when moisture is trapped inside your ear, which creates an ideal environment for bacteria to grow.

When it lasts fewer than 6 weeks, it’s called acute swimmer’s ear. If it lasts longer than 3 months, it’s referred to as chronic swimmer’s ear. About 95 percent of cases are acute.

You may develop swimmer’s ear more frequently if you:

  • swim frequently
  • live in a humid environment
  • have narrow ear canals
  • wear a hearing aid
  • use earbud earphones
  • have had ear trauma

Other potential causes

Some other potential causes of a swollen ear canal include the following:

  • A cut in your ear canal. Bacteria can get into small cuts and wounds in your ear canal and cause an infection.
  • Fungal infections. In rare cases, fungi such as Candida or Aspergillus may overgrow in your ear. Fungal infections may also occur after prolonged antibiotic use.
  • Ear trauma. A direct blow to your ear may lead to swelling and inflammation. Some potential causes are sports injuries, car accidents, or assaults.
  • Foreign matter in your ear. A foreign object in your ear can potentially attract dirt and bacteria.
  • Using cotton swabs. Cotton swabs can push bacteria and ear wax farther into your ear and lead to an infection.
  • Allergic reaction. An allergy to a hair product such as a shampoo or conditioner can potentially lead to swelling and discomfort inside your ear.

Along with swelling of your ear canal, other symptoms of swimmer’s ear can include:

  • redness or discoloration
  • heat in your affected ear
  • reduced ability to hear
  • fluid discharge
  • itchiness
  • pus
  • fever
  • pain
  • pain when tugging on your affected ear

Depending on the severity of the infection, swimmer’s ear can cause pain that ranges from mild to severe.

Other causes of ear canal swelling can lead to similar symptoms. But if direct injury is the cause, you’re unlikely to develop pus or a fever unless an infection develops later.

If you have a swollen ear canal with mild pain and no other symptoms, you may want to wait a couple of days before you contact a doctor. Sometimes a mild ear infection can clear up on its own in a couple of days.

But it’s important to follow up with a healthcare professional if:

  • the pain gets worse
  • the pain and swelling don’t go away after 1 to 2 days
  • you start running a fever
  • you notice discharge coming from your ear
  • you have a harder time hearing

In some cases — especially mild cases — an ear infection may heal on its own without any particular treatment.

With a bacterial infection, the most common treatment is antibiotic ear drops and drugs to help manage pain. A 2015 research review showed oral antibiotics to be beneficial.

Some of the most common antibiotics used to treat swimmer’s ear include the following:

  • a total of 3 to 4 drops of Polymyxin B, neomycin, and hydrocortisone four times per day
  • ofloxacin drops, usually 5, twice daily
  • a combination of 3 drops of ciprofloxacin with hydrocortisone twice daily

If you’re experiencing a fungal infection, your doctor will likely prescribe antifungal drops.

For mild to moderate pain, acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs are usually effective.

Antihistamines and decongestants may help relieve symptoms caused by allergies.

To avoid an infection and swelling in your ear canal, it’s a good idea to take precautions to avoid getting bacteria or moisture in your ears. You can do this by taking the following steps.

The most common cause of an ear canal that’s swollen shut is a bacterial infection known as swimmer’s ear. Swimmer’s ear can develop if you get moisture in your ears. Drying your ears completely after bathing or swimming can help prevent an infection and swelling in your ear canal.

If you think you may have an ear infection, it’s a good idea to contact your doctor so you can get the correct treatment. The typical treatment for a swollen ear canal involves antibiotic ear drops. If you have a fungal infection, your doctor will usually prescribe antifungal ear drops.