An ear infection is inflammation and fluid buildup in part of the ear, usually caused by bacteria or viruses. It’s one of the most common reasons children visit a doctor: roughly 40% of kids have at least one episode by age three, and older studies tracking children over longer periods found that number climbs above 80%. Adults get them too, though far less frequently. Ear infections can affect three different parts of the ear, and the type you have determines the symptoms, severity, and treatment.
Three Types Based on Location
Your ear has three distinct sections, and infections in each one feel and behave differently.
Outer ear infections affect the ear canal, the roughly 2.5-centimeter tube running from the visible part of your ear to the eardrum. This type behaves like a skin infection and is often called swimmer’s ear because moisture trapped in the canal creates a breeding ground for bacteria or fungi. Pain when you tug on your ear or press near the opening is the hallmark sign.
Middle ear infections are the most common type, especially in children. The middle ear is a small air-filled space behind the eardrum, connected to the back of your throat by a narrow tube called the eustachian tube. When that tube swells shut from a cold or allergies, fluid gets trapped behind the eardrum and bacteria multiply. This is what most people mean when they say “ear infection.”
Inner ear infections are rarer and more disorienting. The inner ear controls both hearing and balance. When it becomes inflamed, a condition called labyrinthitis, you can experience sudden vertigo, nausea, vomiting, and hearing loss in one ear. Symptoms develop over several hours, peak within the first one to two days, and typically resolve on their own within days, though balance problems can linger.
What Causes Ear Infections
Middle ear infections usually start with a viral upper respiratory infection, a common cold. The virus causes swelling in the eustachian tube, trapping fluid behind the eardrum. Bacteria then colonize that fluid, turning what started as congestion into an active infection. In some cases, viruses alone cause the inflammation without bacteria being involved at all.
Children are more susceptible for a simple anatomical reason: their eustachian tubes are shorter, more horizontal, and narrower than adult tubes. That makes them easier to block and harder to drain. As children grow, the tubes lengthen and angle downward, which is why ear infections become less common with age.
Outer ear infections are typically caused by bacteria already present on the skin that get an opportunity to multiply when the canal stays damp or gets scratched from cotton swabs or earbuds. Fungal infections of the outer ear are less common but do occur, particularly in warm, humid climates.
Symptoms in Children and Adults
The core symptoms of a middle ear infection are ear pain, fever, and difficulty sleeping. In young children who can’t describe what they feel, you’ll notice fussiness, irritability, and rubbing or tugging at one ear. Some children lose their appetite because swallowing changes the pressure in the middle ear and makes the pain worse.
Adults tend to notice a feeling of fullness or pressure in the ear, muffled hearing, and a dull or sharp ache. Fluid draining from the ear signals that the eardrum has ruptured, which sounds alarming but actually relieves pressure and pain. Most eardrum ruptures heal on their own within about 72 hours.
Inner ear infections feel distinctly different. The dominant symptom is vertigo, a spinning sensation that’s constant rather than coming in brief episodes. Nausea and vomiting are common. You may veer or fall toward the affected side when walking. If hearing loss accompanies the dizziness, that points specifically to labyrinthitis rather than a related condition called vestibular neuritis, which spares hearing.
How Ear Infections Are Diagnosed
Doctors diagnose middle ear infections by looking at the eardrum with an otoscope, a handheld device with a light and magnifying lens. A healthy eardrum is translucent and moves easily when a small puff of air is blown against it. An infected eardrum looks red, swollen, and opaque, and it doesn’t move well because of the fluid pressing behind it. That bulging, reddened appearance is the key finding that distinguishes an active infection from fluid sitting harmlessly in the middle ear without infection, a condition called otitis media with effusion.
Clinical guidelines specify that a middle ear infection shouldn’t be diagnosed without evidence of trapped fluid. This matters because unnecessary antibiotics are a common problem, and fluid alone without signs of infection doesn’t need them.
Treatment and Recovery
Not every ear infection needs antibiotics. Many middle ear infections, particularly mild ones in children two and older, resolve on their own within a few days. Doctors sometimes recommend a “watch and wait” approach for 48 to 72 hours, treating pain with over-the-counter pain relievers while the immune system works.
When antibiotics are prescribed, duration depends on the child’s age and severity. For children two and older with non-severe infections, national guidelines recommend 5 to 7 days of antibiotics rather than the traditional 10-day course. Younger children or those with severe symptoms may still receive the longer duration. Most children feel noticeably better within the first two to three days of treatment.
Outer ear infections are treated differently, usually with antibiotic or antifungal ear drops applied directly into the canal. Keeping the ear dry during treatment speeds recovery.
Inner ear infections typically resolve without specific treatment. The main challenge is managing vertigo and nausea while the inflammation subsides.
Risk Factors You Can Control
Several environmental factors increase how often children get ear infections. Exposure to cigarette smoke is one of the most studied. Children exposed to parental smoking both before and after birth have a 24% higher risk of recurrent ear infections compared to unexposed children. Smoke irritates the lining of the eustachian tube, causing it to produce excess mucus and clear bacteria less effectively.
Daycare attendance is another well-established risk factor, simply because more exposure to other children means more colds, and more colds mean more opportunities for fluid to build up behind the eardrum. Breastfeeding, on the other hand, appears protective. Breast milk contains antibodies that help fight the infections responsible for triggering ear problems. Feeding infants in an upright rather than flat position also helps prevent milk from flowing into the eustachian tube.
Complications Worth Knowing About
Most ear infections clear up completely, but complication rates range from 5% to 12.5%. The most common complication is temporary hearing loss. Fluid behind the eardrum dampens sound, causing mild hearing loss in the range of 10 to 40 decibels. That’s roughly the difference between hearing a whisper clearly and not hearing it at all. Hearing normally returns once the fluid drains, but in young children, even temporary hearing loss during critical developmental windows can delay speech and social skills.
About 15% of adolescents who had ear infections as children show hearing thresholds above 25 decibels, and research has found that subtle hearing abnormalities in areas like processing speech in noisy environments can persist long after the infections are gone.
Mastoiditis, an infection of the honeycomb-like bone behind the ear, is the most common serious complication. It happens when infection spreads from the middle ear into that bone. Symptoms include swelling and redness behind the ear, fever, and the ear being pushed forward. It requires prompt treatment, sometimes with surgery.
In rare cases, infection can spread to the inner ear, causing permanent hearing loss, persistent dizziness, or ringing in the ears. Even rarer are intracranial complications like meningitis or brain abscess, which occur when infection penetrates the thin bone separating the ear from the brain. These are uncommon with modern treatment but underscore why persistent or worsening symptoms after several days shouldn’t be ignored.