Types and symptoms
Allergy types
Airborne allergens like pollen and ragweed, for example, can affect up to 35 million Americans with allergic reactions. The types of pollen that most commonly cause allergic reactions are produced by the plain-looking plants (trees, grasses, and weeds) that do not have showy flowers. Some people say they are allergic to colorful or scented flowers like roses. In fact, only those who have prolonged, close contact with flowers (like florists) are likely to be sensitive to pollen from these plants.
Animal allergies most often include household pets. People may think that pet allergy is brought on by the fur of cats and dogs, but researchers have actually found that the major allergens are proteins in the saliva. These proteins stick to the fur when the animal licks itself. Carpet and furniture are reservoirs for pet allergens, and the allergens can remain there several weeks. The allergens from pets can also stay in household air for months after the animal is gone.
Mold allergies . When inhaled, tiny fungal spores, or sometimes pieces of fungi, may cause allergic rhinitis (also called hay fever). Because they are so small, mold spores can also reach the lungs. In a small number of people, symptoms of mold allergy may be brought on or worsened by eating certain foods such as cheeses processed with fungi. Occasionally, mushrooms, dried fruits, and foods containing yeast, soy sauce, or vinegar will produce allergy symptoms.
Dust mite allergy is an allergy to a microscopic organism that lives in the dust found at home or work. House dust and some house furnishings contain these microscopic mites. Dust mites are perhaps the most common cause of perennial allergic rhinitis/hay fever. House dust mite allergy usually produces symptoms similar to pollen allergy and also can produce symptoms of asthma.
Food allergy is an abnormal response to a food triggered by the body’s immune system. Allergic reactions to food can sometimes be severe, resulting in illness and even death. Sometimes, a reaction to food is not an allergy at all but another type of reaction called “food intolerance.” Food intolerance is more common than food allergy.
Symptoms of allergies
There is a range of symptoms associated with various allergies. For airborne and other allergies, the symptoms often include sneezing or watering eyes; itchy eyes, nose or throat; and coughing or a runny nose. Some people with allergies develop asthma. Allergies can complicate asthma and add additional symptoms like constricted airways and shortness of breath.