What Are Allergies?

Allergies are reactions caused by the immune system as it attacks environmental substances that are typically harmless to most people. They may occur in response to a range of different materials (called allergens), including food, pollen, dust mites, animals, insect bites, or medicines. Over 50 million children and adults in the U.S. have allergies, and allergies are the sixth leading cause of chronic illness in the country.

An allergy can affect different parts of the body. Allergic rhinitis, or hay fever, impacts the nose and eyes, while eczema affects the skin. Food allergies can influence the gut, skin, air passageways, lungs, and at times, the whole body through the blood vessels.

Conditions like asthma, which also affect the lungs, are closely related to allergies. However, the underlying causes are not the same.

How Exactly Do Allergies Work?

With allergies, your immune system responds to harmless substances that it misidentifies as foreign invaders. Histamines and other chemicals are released by the body to rectify the issue, which leads to common allergy symptoms like sneezing, itchy nose or eyes, runny nose, and watery eyes. For people who suffer from seasonal allergies, this histamine response may continue throughout most of the spring season.

This reaction persists every time you come into contact with the allergen in the future. Your immune system then creates antibodies to target that specific allergen. And the next time you are exposed to the allergen, the immune system will attack.

The word “allergy” comes from ancient Greek terms for “other work.” This refers to the tendency of some immune systems to experience abnormal reactions to “normal” substances in their environment.

The most common allergens include:

  • Pollen, trees, and plants
  • Specific medicines
  • Animal dander
  • Dust mites
  • Mold
  • Insects that sting (bee, wasp, fire ant); bite (mosquito, tick); or are household pests (cockroaches)
  • Latex
  • Particular foods (eggs, dairy, peanuts, and shellfish)

What are the Symptoms of Allergies?

Allergies have a unique symptom profile. Symptoms typically depend on the kind of allergy and its severity. The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis (a life-threatening reaction).

Allergenic symptoms for nasal allergies can include:

  • Clear, runny mucus
  • Dry coughing
  • Sneezing
  • Itchy, watery eyes
  • Feeling unwell or sick

Hay fever, also called allergic rhinitis, can cause:

  • Sneezing
  • Itching of the nose, eyes, or roof of the mouth
  • Runny, stuffy nose
  • Watery, red or swollen eyes (conjunctivitis)

Food allergies may cause tingling or inflammation in the mouth, throat, or face as well as hives. Rash, swelling of the face, or wheezing can arise from certain medications. And bee or insect allergies can cause swelling at the site of the sting, extreme itching, shortness of breath, or coughing. Some allergies can recur seasonally like clockwork, or they can last year-round if you have dust mites or mold allergy.

Other more severe symptoms, like trouble breathing and swelling in your mouth or throat, may lead to anaphylaxis. A life-threatening medical emergency, anaphylaxis can cause you to go into shock. Signs and symptoms of anaphylaxis include:

  • Loss of consciousness
  • A drop in blood pressure
  • Severe shortness of breath
  • Skin rash
  • Lightheadedness
  • A rapid, weak pulse
  • Nausea and vomiting

While most allergies can’t be cured, treatments can help relieve your symptoms.

How are Allergies Treated?

Proper allergy treatment is based on your medical history, the results of your allergy tests, and the severity of your symptoms. Treatment may include avoiding allergens, administering medication, or undergoing immunotherapy (allergens given as a shot or placed under the tongue).


The best way to prevent allergy symptoms and limit the need for allergy medicine is to avoid allergens as much as possible. This includes removing the source of allergens from your home, office, and other places where you spend time. You can also reduce your symptoms to airborne allergens by washing out your nose daily.

If you’re allergic to pollen, stay inside with windows and doors closed when pollen is high. If you have a dust mite allergy, dust, vacuum, and wash your bedding often.


If changing the environment fails to provide relief, or it isn’t feasible, many safe prescription and over-the-counter medicines exist to relieve allergy symptoms. They include:

  • Nasal corticosteroids are nose sprays – to reduce swelling
  • Antihistamines
  • Mast cell stabilizers – prevents your body from releasing histamine
  • Decongestants
  • Corticosteroid creams or ointments – relieve itchiness and stop the spread of rashes
  • Oral corticosteroids – to decrease swelling and stop severe allergic reactions
  • Epinephrine – some people might need to carry an emergency epinephrine shot at all times. An epinephrine shot can reduce symptoms until emergency treatment arrives.

Your medical care provider can help you determine which medications are most appropriate for your allergies.


Allergen immunotherapy, also known as allergy shots, is a form of long-term treatment that decreases symptoms for many people living with allergies. Both children and adults can receive allergy shots, although they are not typically recommended for children under age five.

Allergy shots decrease sensitivity to allergens and often lead to lasting relief of allergy symptoms even after treatment is stopped. This makes it a cost-effective, beneficial treatment approach for many.

With immunotherapy, your body is exposed to small amounts of what you are allergic to, and over the course of months to years, the immune system develops a defense against these allergens. This type of treatment prevents allergic reactions from occurring in the first place. It is the only form of therapy that targets the issue at the root cause.

Immunotherapy is individualized based upon each patient’s allergy profile. Many people benefit from allergy shots for many years after receiving a full course of shots.

To learn more about your allergies and how you may benefit from one particular treatment over another, please feel free to contact us.