About Allergies: Allergy Symptoms, Causes and Treatments Image

Allergy symptoms are very common in industrialized nations. According to the American Academy of Allergy, Asthma and Immunology, over 54 percent of all Americans test positive for at least one allergen. This number may be on the rise as allergy cases have doubled in the last 20 years.

What Are Allergies?

The human immune system is designed to identify and destroy foreign substances that pose a threat to health, such as bacteria and parasites. In most cases, the immune system correctly identifies which substances are threats and which can be safely ignored.

Allergy symptoms occur when the immune system mistakenly believes a harmless substance is a threat. The substance that triggers allergy symptoms is called an “allergen.” When the immune system recognizes this allergen, it produces large quantities of IgE antibodies, which are proteins that bind to the allergen and activate processes that promote its elimination. The processes produce inflammation and other allergy symptoms as a result.

Most people can develop an allergic reaction. People with a family history of allergies are at highest risk of developing allergies themselves. Exposure to pollution, infection and smoking can also cause allergy symptoms.

Types of Allergies

Many different substances cause allergy symptoms. Common types of allergies include:

  • Allergic rhinitis (or “hay fever,” caused by exposure to airborne particles)
  • Food allergy
  • Insect sting/bite allergy
  • Latex allergy
  • Medication allergy
  • Milk allergy
  • Sinusitis.

About Allergy Symptoms

Most people associate sneezing, runny noses and congestion with allergy symptoms. These are symptoms of hay fever, caused by exposure to pollen and other airborne allergens.

Allergy symptoms can affect the skin, eyes, nose, lungs and stomach, depending on the type of allergy:

  • Drug allergy symptoms are capable of causing anaphylaxis and hives.
  • A food allergy can cause swelling of the lips, tongue and throat, a tingling sensation in the mouth, hives and even anaphylaxis.
  • Insect bite allergy symptoms can include hives and anaphylaxis, in addition to swelling around the bite, wheezing, coughing and shortness of breath.
  • Skin allergy symptoms include itchy, red skin that may also flake or peel.

Dangerous Allergy Symptoms: Anaphylaxis and Hives

Anaphylaxis is a serious allergic response most often seen with drug, insect bite and food allergies. Also known as allergic shock, anaphylaxis causes a sudden and dangerous drop in blood pressure that affects multiple organs. Without emergency treatment, anaphylaxis can be fatal.

A hive is a skin reaction that causes swelling and red, itchy skin. Hives can develop anywhere on the skin. Swelling around the face, mouth, lips or throat can make breathing difficult.

Treating Allergies

Treatment for allergies is often available to reduce or help avoid allergy symptoms. The best option is to avoid the allergen altogether, but this is not always possible.

Allergy medication, including antihistamines and corticosteroids, can reduce allergy symptoms. Both over-the-counter and prescription allergy medication are available.

Severe allergy symptoms are sometimes treated by an allergist with immunotherapy, a series of injections of the allergen that helps the body slowly build up a resistance to the allergen’s effects. An allergist is a doctor who specializes in the diagnosis and treatment of allergic diseases.

Exposure to an insect or food allergy capable of causing anaphylaxis requires emergency medical treatment. People with anaphylactic-causing allergies may carry an epinephrine “pen,” a self-injecting device that reduces dangerous allergy symptoms long enough to get to a hospital.


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Mayo Clinic Staff. (2009). Allergies. Retrieved March 24, 2010, from the Mayo Clinic Web site:

National Institute of Allergy and Infectious Diseases Staff. (2010). Allergy. Retrieved March 24, 2010, from the MedlinePlus Web site:

Szeftel, A. (2007). Allergy/allergies. Retrieved March 24, 2010, from the MedicineNet Web site: