An allergy is the immune system’s response to a foreign substance that’s not typically harmful to your body. These foreign substances are called allergens. They can include certain foods, pollen, or pet dander. They elicit a response from your immune system.

Your immune system’s job is to keep you healthy by fighting infection and other harmful pathogens. It does this by attacking anything it fears could put your body in danger. Depending on the allergen, this attack response may involve inflammation, sneezing, and a host of other symptoms.

Your immune system normally becomes acclimated to your environment. When your body encounters something like pet dander, it realizes it’s harmless, and doesn’t attack. In people with allergies, the immune system confuses those harmless substances with outside invaders threatening the body.

Allergies are common, and there are several ways to treat them in order to avoid annoying and troublesome symptoms.

Causes and Types of Allergies

Allergies occur when a normally harmless foreign substance enters the body and your immune system has a response to the invader. Researchers aren’t exactly sure why the immune system reacts this way.

Allergies have a genetic component, meaning that they can be passed down from parent to child. However, only a general susceptibility to allergic reaction is genetic. Specific allergies are not passed down. If your mother is allergic to shellfish, it doesn’t necessarily mean that you will be too.

According to the American College of Allergy, Asthma & Immunology, there are several common types of allergens, including:

  • animal products: pet dander, dust mite waste, cockroaches
  • drugs: penicillin, “sulfa” drugs
  • foods: most commonly wheat, nuts, milk, shellfish, and eggs
  • insect stings: bees, wasps, mosquitoes
  • mold: airborne spores from mold
  • plants: pollens from grass, weeds, and trees, as well as resin from plants such as poison ivy and poison oak
  • other: metals, such as copper and latex

Seasonal allergies, also known as hay fever, are some of the most common allergies. These are caused by pollen released by plants. They cause:

  • itchy eyes
  • watery eyes
  • a runny nose
  • a cough

When to See a Doctor About Allergies

Allergy symptoms can create numerous complications.

Food allergies can trigger swelling, hives, nausea, fatigue, and more. It may take awhile for a person to realize that they have a food allergy. If you have a serious reaction after a meal and you’re not sure why, see your doctor. They will be able to find the exact cause of your reaction or refer you to a specialist.

Hay fever symptoms can mimic those of a cold. They include congestion, a runny nose, and swollen eyes. Most of the time you’ll be able to manage these symptoms at home using over-the-counter treatments. See your doctor if your symptoms become unmanageable.

Severe allergies can cause anaphylaxis. This is a life-threatening emergency that can lead to breathing difficulties, lightheadedness, and loss of consciousness. If you’re experiencing these symptoms after coming in contact with a possible allergen, seek medical help immediately.

Your doctor can help determine the cause of your symptoms, as well as the difference between a sensitivity and a full-blown allergy. Your doctor can also teach you how to manage your allergy symptoms.

How Are Allergies Diagnosed?

There are several ways allergies can be diagnosed.

First, your doctor will ask about your symptoms and perform a physical exam. They will ask about anything unusual you may have eaten recently and any substances you may have come in contact with. For example, if you have a rash on your hands your doctor may ask if you’ve put on latex gloves recently.

Food allergies are typically diagnosed through a process of elimination. Your doctor may have you take part in an elimination diet. This means you will remove certain foods from your diet and then rate your symptoms. Foods are slowly added back into the diet and symptoms are recorded in a food diary.

Your doctor may also refer you to an allergist for testing and treatment. A common type of allergy test carried out by an allergist is called a skin test. During this test, your skin is pricked or scratched with small needles containing potential allergens. Your skin’s reaction is documented. If you’re allergic to a particular substance, your skin will become red and inflamed.

According to the Mayo Clinic, your doctor or allergist may also order a blood test known as a radioallergosorbent test (RAST). Your blood will be tested for the presence of allergy-causing antibodies, or cells that react to allergens.

How Are Allergies Treated?

The best treatment for allergies is avoiding whatever triggers the reaction. If that’s not possible, there are treatment options available.


Since people with hay fever and seasonal allergies cannot avoid the outdoor environment forever, treatment involves medications like antihistamines to control the symptoms. The medication can be over-the-counter or prescription, depending on the severity of your allergies.

Allergy medications include:

  • antihistamines
  • corticosteroids
  • cromolyn sodium
  • decongestants
  • leukotriene modifiers


Many people opt for immunotherapy. This involves several injections of purified extracts from the allergens given over a few years. This helps the body become accustomed to the substance that produces the allergic reaction. Successful immunotherapy can prevent allergy symptoms from returning.

Emergency Epinephrine

People who have severe, life-threatening allergic reactions typically carry an emergency epinephrine shot, commonly called an EpiPen. EpiPen is one brand name and another commonly used brand is Tinject. This shot is given to counter the allergic reaction until medical help arrives.

There are many natural treatments and supplements marketed to treat allergies, but you should discuss these with your doctor before trying them. Some natural treatments may contain other allergens.

How to Prevent Allergies

There is no way to prevent allergies. But there are ways to prevent the symptoms from occurring. The best way to prevent allergy symptoms is to avoid the allergens that trigger them.

Avoidance is the most effective way to treat food allergens. Trying an elimination diet can help you determine the cause of your allergens so you know how to avoid them. Thoroughly reading food labels and asking questions while dining out are basic steps to help avoid food allergens.

Preventing seasonal allergies, contact allergies, and other allergies comes down to knowing where the allergens are located and how to avoid them. If you’re allergic to dust, installing proper air filters in your home, getting your air ducts professionally cleaned, and regularly dusting your home can help reduce symptoms.

Proper allergy testing can help you pinpoint your exact triggers, which makes them easier to avoid.

Outlook: Living With Allergies

Allergies are common and don’t have life-threatening consequences for most people. Those at risk of anaphylaxis can learn how to manage their allergies and what to do in an emergency situation.

Most allergies are manageable with avoidance, medications, and lifestyle changes. Working with your doctor or allergist can help reduce any major complications and make life more enjoyable.