Ear infections are one of the most common illnesses of childhood. They are caused by bacteria, fungi and viruses. In most cases, these germs enter a child’s ear after a cold or the flu – and can cause irritation, inflammation and fluid buildup within the ear. Getting a cold or the flu puts a child at increased risk of an ear infection. Children with a history of allergies or asthma may also face an increased risk of ear infection.

The following may also increase a child’s risk of developing ear infections:

• Lowered immune system response. Anything that affects a child’s immune system, lowering its ability to effectively fight off infection, can increase the risk of ear infections. This includes a child’s age (the immune system is not fully developed until about age 7), or any medical conditions that compromise immune system function.
  
  
• Gender. Boys tend to be slightly more affected by ear infections than girls.
  
  
• History of ear infections. Children who have had previous ear infections may be more likely to experience them again. Children with a family history of ear infection have an increased risk of ear infections.
  
  
• Conditions that affect structure, size or shape of the nose, ear and throat. Children born prematurely or with low birth weight may have smaller-than-average eustachian tubes (air tunnels from the back of the throat to the middle ear), increasing their risk of ear infections. Children with Down syndrome or a cleft palate may also have structural differences within their respiratory system that can make ear infections more likely.
  
  
• Large daycare facilities. Attending daycare facilities with large groups of children can increase the risk of a child contracting a cold or flu virus, which may lead to ear infections.
  
  
• Feeding with formula. Breastfeeding provides antibodies to infants, which can provide a level of protection against ear infections. Using formula to feed an infant may increase the infant’s risk of ear infections.
  
  
• Drinking while lying down. Lying down while drinking promotes infection because liquid may travel up the eustachian tubes, increasing the risk of infection. This may include children who fall asleep with a bottle in their mouths.
  
  
• Exposure to cigarette smoke. Second-hand smoke increases the risk of infections, including ear infections. Children of smokers have more colds and ear infections than children of nonsmokers, according to some studies.
  
  
• Use of pacifiers. Infants (especially those between the ages of 6 months and 12 months) who use pacifiers have a higher risk of developing ear infections. Thumb sucking does not appear to increase the risk of ear infection. Limiting pacifier use in infants over 6 months of age to the times when the child is falling asleep may help reduce the risk.
  
  
• Swimming. Exposing the ear canal (passageway from the outer ear to the eardrum) to excess moisture or contaminated water can increase the risk of infection.
  
  
• Excess earwax. Buildup of wax in the ears may trap fluid in the ear canal and lead to an outer ear infection (swimmer’s ear).
  
  
• Foreign objects in ear canal. Skin lining the ear canal may become stretched or injured when foreign objects (e.g., cotton swabs, bobby pins, beans) enter the ear canal, causing an ear infection.
  
  
• Ear piercing. The use of unsterile equipment or jewelry, frequent handling of the pierced ear with dirty hands and piercing the cartilage of the ear – instead of the earlobe – can increase the risk of infecting the exterior ear (auricle). Infection may also occur when earrings are too tight or when they scratch the ear.
  
  
• Injuries to the external ear. This can provide an opportunity for germs to penetrate the skin of the ear canal, causing an ear infection.
  
  
• Use of irritating chemicals near the ear. Chemicals in hair spray, hair dye and other cosmetic products may irritate the skin of the ear canal, making it more vulnerable to infection.