Allergies are a very common disorder that affects more than 50 million Americans.

Allergies are caused by an overactive immune system. The immune system incorrectly identifies an otherwise harmless substance in the environment as harmful, and then attacks this substance with fierceness far greater than required. These substances do not normally cause most people's immune systems to react.

When a person with an allergy is exposed to allergens (mold, pollen, etc.), the body will start to produce antibodies known as IgE to fight these allergens. The antibodies attach themselves to allergy blood cells known as mast cells to fight the perceived allergens. These mast cells then release chemicals that cause allergy symptoms. One of the chemicals that the cells release is Histamine. This chemical causes symptoms like itchiness and a runny nose.

If the person with allergies is exposed to airborne allergens like mold and pollen, the symptoms will occur in the nose, eyes and lungs. If the allergens are taken in through the mouth, the allergic reaction will happen in the mouth, stomach, and intestines.

Allergy symptoms vary according to what is causing the reaction and the part of the body the reaction occurs. Typical allergy symptoms are as follows:

• Congestion in the sinus region
• Difficulty breathing
• Rash
• Watery eyes
• Abdominal pain
• Vomiting
• Diarrhea
• Drop in blood pressure
• Mental confusion
• Swelling
• Runny nose
• Swollen eyes
• Red eyes
• Coughing
• Hives
• Headaches
• Wheezing
• Itching of eyes and nose

Some people inherit allergic tendencies, but some are fortunate enough not to inherit them.

For the sake of clarity, allergens mentioned in this article will be identified according to categories of food and airborne and chemical allergens. The following are different types and classes of allergens:

Airborne allergens

The following are airborne allergens:

• Pollen (grass and tree pollen)
• Mold spores
• Animal dander

Food allergens

The following are food allergens:

• Dairy products
• Eggs
• Strawberries
• Fish and Shellfish
• Cereals
• Peanuts
• Corn flour
• Soy flour
• Potato starch
• Rice flour
• Yeasts
• Lactose

Chemical allergens

The following are chemical allergens:

• Nickel sulphate
• Wool alcohols
• Neomycin sulphate
• Cobalt chloride
• Thiomersal (thimerosal, merthiolate)
• Formaldehyde (N-hydrnxymethyl succinimide)
• p-Phenylenediamine (PPD)
• Mercaptobenzothiazole (MBT)
• Quaternium-15
• Balsam of Pew
• Epoxy resin

Treatment of food allergies:

• The recommend way to treat food allergies is to avoiding allergy causing food.
• It is therefore critical that individuals with an allergy carefully read the ingredients on food they consume.

Treatment of allergies caused by airborne allergens:

• Antihistamines, nasal corticosteroid sprays, and decongestants treat allergies caused by airborne allergens.