There are three types of allergies: ingested allergies, contact allergies, and inhaled allergies. An allergic response occurs when your immune system reacts abnormally to a common substance in the ...

Pollen is the most common cause of allergic rhinitis. Pollen is microscopic in size. Pollen from trees, grasses and weeds is easily windblown and known to cause allergies. Pollen is the tiny ...

It can be caused by viral or fungal infections or allergies to food, pollen, latex, medications, and more. If it’s caused by allergies, an itchy mouth is often referred to as oral allergy syndrome.