Allergies

Medically reviewed by Judith Marcin, MD on October 26, 2016Written by Brian Krans

Allergies

An allergy is an immune system 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.

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

Your immune system normally adjusts to your environment. For example, when your body encounters something like pet dander, it should realize it’s harmless. In people with dander allergies, the immune system perceives it as an outside invader threatening the body and attacks it.

Allergies are common, and several treatments can help you avoid annoying and troublesome symptoms.

Causes and types of allergies

Researchers aren’t exactly sure why the immune system causes an allergic reaction when a normally harmless foreign substance enters the body.

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. For instance, 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, common types of allergens include:

  • animal products: pet dander, dust mite waste, cockroaches
  • drugs: penicillin, sulfa drugs
  • foods: wheat, nuts, milk, shellfish, 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: latex, metals

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
  • runny nose
  • coughing

When to see a doctor about allergies

Allergy symptoms can create many complications. 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.

For food allergies

Food allergies can trigger swelling, hives, nausea, fatigue, and more. It may take a while 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 a medical professional immediately. They can find the exact cause of your reaction or refer you to a specialist.

For seasonal allergies

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

For severe allergies

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.

How allergies are diagnosed

Allergies can be diagnosed in several ways. First, your doctor will ask about your symptoms and perform a physical exam. They’ll also 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 put on latex gloves recently.

Process of elimination

Food allergies are typically diagnosed through a process of elimination. Your doctor may have you follow an elimination diet. This means you remove certain foods from your diet and then rate your symptoms. Then you slowly add foods back into the diet and record your symptoms in a food diary.

Skin test

Your doctor may also refer you to an allergist for testing and treatment. A skin test is a common type of allergy test carried out by an allergist. 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.

Blood test

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 (cells that react to allergens).

Allergy treatments

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

Medication

Allergy treatment often includes medications like antihistamines to control symptoms. The medication can be over-the-counter or prescription, depending on the severity of your allergies.

Allergy medications include:

Immunotherapy

Many people opt for immunotherapy. This involves several injections over the course of a few years to help the body get used to your allergy. Successful immunotherapy can prevent allergy symptoms from returning.

Emergency epinephrine

If you have a severe, life-threatening allergy, you should carry an emergency epinephrine shot. The shot counters allergic reactions until medical help arrives. Common brands of this treatment include EpiPen and Twinject.

Alternatives

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.

Preventing symptoms

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 prevent food allergy symptoms. An elimination diet can help you determine the cause of your allergies so you know how to avoid them. To help you avoid food allergens, thoroughly read food labels and ask questions while dining out.

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

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

Living with allergies

Allergies are common and don’t have life-threatening consequences for most people. People who are 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.

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