Advice from Doctors

I often see children that I suspect have ear infections (otitis media). The parents of the child have many questions -- what are ear infections? Why do they happen?

Ear infections typically occur between the ages of six months and two years of life, but they can happen at any age. According to the National Institute on Deafness and Other Communication Disorders, 75 percent of all children have at least one ear infection by the time they are three years old.

These infections are most frequently associated with pain, fever, and sleep disturbances but can also lead to behavior problems and speech issues if associated with hearing loss due to persistent fluid in the ear. Dr. Martha Snyder, a primary care pediatrician at Duke, tells us what they are and how they happen.

-- Dennis Clements MD, PhD, MPH

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Martha Snyder, MD

About Ear Infections

The ear is composed of three parts: the outer ear, the middle ear, and the inner ear.

The outer ear is the space from the ear drum (tympanic membrane) to the outside of the ear. When this canal gets infected it is called swimmer’s ear or otitis externa. The middle ear is the air-filled space behind the ear drum. When the middle ear gets infected it is commonly called an ear infection or acute otitis media. The inner ear is where the hearing and balance organs are located.

The Eustachian tube is the passage from your middle ear to your throat. It is usually closed but opens regularly to ventilate the middle ear. In children this tube is shorter, floppier, and more horizontal; this makes the middle ear more prone to retain fluid.

As you grow this tube becomes longer and angled, making the middle ear less likely to retain the fluid that is required for viral or bacterial growth.

You cannot catch an ear infection from other people, but you can catch the cold that can lead to the fluid accumulation that makes a person more prone to an ear infection.

Ear infections generally start as a viral upper respiratory infection that causes fluid to build up in the middle ear space. However, dysfunction or swelling of the Eustachian tube can also lead to fluid accumulation as can blocking of the Eustachian tube by enlarged adenoid tissue.

An infection then occurs when a germ, either a virus or bacteria, invades the fluid and begins to multiply unchecked by the body defenses. A virus cannot be treated by an antibiotic, but bacteria can be treated by an antibiotic. Both types of infection can cause pain and/or fever. About 60 percent of all ear infections are believed to be bacterial and 40 percent are believed to be viral.

The bacteria most commonly associated with ear infections are:

• Streptococcus pneumoniae (also called S. pneumoniae or pneumococcus) is responsible for about 40 to 80 percent of ear infections
• Haemophilus influenzae is responsible for 20 to 30 percent of ear infections
• Moraxella catarrhalis is responsible for 10 to 20 percent of ear infections
• Less common bacteria are Streptococcus pyogenes and Staphylococcus aureus

Of note, about 15 percent of these bacteria are now believed to be resistant to the first-choice antibiotics.

The viruses most commonly associated with ear infections are:

• Rhinovirus being the most common
• Respiratory syncytial virus (RSV)
• Influenza (flu)

Warning Signs

Your child may have an ear infection if he or she shows these symptoms:

• Fever
• Ear pain
• Fussiness or irritability, especially with lying down (this increases the pressure in the inner ear causing more pain when an infection is present)
• Disturbed sleep patterns
• Decreased ability to hear
• Feeling of increased pressure in the ear in older children
• Loss of balance
• Fluid draining from the ear

Diagnosing an Ear Infection

Your child’s doctor will need to look at your child’s ear in order to determine what treatment is needed. In the office the doctor will use an otoscope (a specialized flashlight) to look at the ear drum (tympanic membrane).

The doctor may also use pneumatic otoscopy, which is when a gentle puff of air is blown at the ear drum in order to determine if there is fluid in the middle ear. Normally the ear drum will move back and forth, but fluid will cause the ear drum not to move.

Occasionally, you may see an instrument called a tympanometer used, which also checks for movement of the ear drum. A soft ear plug is inserted into the opening of the ear. The plug includes a device that changes air pressure inside the ear.

None of these methods are painful, but the instruments can look intimidating to your child.

Treatment

What is seen in the ear will determine what line of treatment will be recommended. If there is only fluid (effusion) that is not infected you may be told to watch your child over the next few days for signs of the fluid becoming infected. Your child’s doctor will also closely monitor the duration of this fluid and assess if your child is at high risk for hearing and/or speech issues.

If there is an infection present, but it is suspected to be viral, your doctor may recommend medications for pain and fever control only. If the infection looks bacterial (this means that there is pus behind the ear drum) then an antibiotic may be prescribed in addition to fever and pain controlling medications. Typically a bacterial ear infection will start to improve after being on an antibiotic for 24 to 72 hours.

It is very important to finish the antibiotic for the number of days prescribed by your child’s doctor. Keep in mind that about 80 percent of all ear infections will improve without antibiotics if given time according to the American Academy of Pediatrics and the American Academy of Family Practitioners.

With young children, you can expect that the doctor will want to re-evaluate your child’s ear again in three to four weeks.

If your child experiences recurrent ear infections, retains chronic fluid in the ear, or experiences hearing loss, your child’s doctor may refer your child to an Ear, Nose, and Throat (ENT) specialist. In certain situations, the ENT will recommend the placement of ear tubes (tympanostomy tubes) and/or removal of the adenoid tissue (adenoidectomy).

How to Prevent Ear Infections

The best way to prevent ear infections is to do things to decrease the chances of building up fluid in the middle ear.

• Avoid others who are ill when possible
• Wash hands to prevent the spread of viruses
• Avoid large group daycares if possible
• Avoid irritants, especially smoke and other environmental pollutants that can cause Eustachian tube dysfunction
• Breastfeed your child
• Do not allow your child to drink while lying down
• Decrease or eliminate pacifier use
• Control seasonal allergies
• Receive the Prevnar vaccine, which covers certain strains of Streptococcus pneumoniae
• Receive the flu shot each year

Take heart -- ear infections are a common infection that children typically grow out of sooner or later.

-- Martha Snyder, MD, is a primary care pediatrician at Duke Children's.

-- Dennis Clements, MD, PhD, MPH, is the chief of primary care pediatrics at Duke Children's Hospital.