Viral Infections

• Many ear infections develop as the result of a cold, which is a viral infection. The infection causes swelling in the body, particularly in the lining of the middle ear. This leads to fluid buildup in the eardrum, which can cause the pain and fever symptoms associated with an ear infection.
  
  

Adenoid Swelling

• The adenoids are tissues that are located near the upper portion of the throat and behind the nose, in close proximity to the eustachian tubes. They normally serve to fight off infection. However, these can sometimes swell or become infected, which affects the eustachian tubes by either blocking the tubes themselves or through the infection's spread, causing an ear infection.
  
  

Bacterial Infections

• When the eustachian tube is working properly, bacteria flow through it, propelled by tiny hairs called cilia. However, if the tube becomes blocked due to a high number of allergens, irritating substances such as cigarette smoke, or as the result of a respiratory infection, the bacteria contained within cannot circulate through the tube and out of the ear. As a result, the bacteria begin to build up and cause ear-infection-related symptoms.
  
  

Why Children Are More Prone

• Children are more likely to have ear infections due to a shorter eustachian tube, which makes the tube more easy to block and create infection. This is especially true for children under the age of 3, according to kidshealth.org. Also, children's immune systems are not as developed as adults, and therefore may be subject to an increased risk of illness.
  
  

Infection Myths

• While many people believe factors such as water in the ear, cold weather or wind in the ear can cause infection, there are only myths. Most ear infections have to do with effects inside within the eustachian tube, not due to external causes, according to the McKinley Health Center.