Most ear-related conditions are triggered by problems with the eustachian tube, which connects the nose to the middle ear. This tube is designed to allow air to flow in so that the pressure on the interior side of the eardrum (tympanic membrane) is equal to the pressure from the outside environment.  It also drains fluid from the middle ear.

However, severe nasal allergies produce mucus that can flow back into the eustachian tube, creating a blockage. The eustachian tube itself also can become inflamed, further closing the passageway. This prohibits air from reaching the middle ear, and keeps fluid from draining out. Common nasal allergy triggers include:

• Pollens. Small, powdery grains of flowering plants that can easily become airborne. These are most often produced by trees, grass and weeds.

  

   
• Molds and mildews. Tiny fungus spores that can become airborne. These often thrive outdoors in soil, vegetation and rotting wood. They can be found indoors as well, especially in damp areas such as basements and bathrooms.

  

   
• Dust mites. Microscopic insects that live within household dust.  They are often found indoors where there is less air circulation and on surfaces like carpets, bedding and stuffed animals.
  
  
• Animal dander. Tiny scales or particles from an animal’s skin. These very often come from a dog or cat.
  
  
• Cockroach debris. Droppings, eggs, saliva and small pieces of outer shell of cockroaches. These can be found indoors, even if an infestation of live pests is not currently a problem.

Recent studies have found that their may be a link between children with food allergies and increased incidences of ear infections. However, the evidence is not conclusive and research into the question continues.