An allergy is the immune system’s response to a foreign substance that is not typically harmful to your body. These foreign substances—such as certain foods, pollen, or pet dander—are called allergens. 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. This attack response, depending on the allergen, may involve inflammation, sneezing, and a host of other symptoms.
Normally, your immune system becomes acclimated to your environment. Your body encounters something like pet dander, 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.
Allergies occur when a normally harmless foreign substance enters the body and your immune system has a hyperactive, exceedingly vigilant response to the invader. Researchers aren’t exactly sure why the immune system reacts this way.
They do know, however, that 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. In other words, if your mother is allergic to shellfish, it doesn’t necessarily mean that you will be too.
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 (ACAAI)
Seasonal allergies, also known as hay fever, are some of the most common allergies. These are caused by pollen released by plants, typically in the spring. They cause itchy, watery eyes, a runny nose, a cough, and more.
Allergy symptoms can create numerous complications.
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 your doctor or a specialist. He or she will be able to find the exact cause of your reaction.
Hay fever symptoms can mimic those of a cold, and include congestion, a runny nose, and swollen eyes. Most of the time, you will 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—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 suspected 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.
There are several ways allergies can be diagnosed.
First, your doctor will ask about your symptoms and perform a physical exam. He or she 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, in which you 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—a sign of an allergic reaction.
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 (Mayo Clinic, 2012).
The best treatment for allergies is avoiding whatever triggers the reaction.
Since people with hay fever and seasonal allergies cannot avoid the outdoor environment forever, treatment involves medications, such as antihistamines, to control the symptoms. The medication can be over-the-counter or prescription, depending on the severity of your allergies.
Allergy medications include:
- cromolyn sodium
- 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.
People who have severe, life-threatening allergic reactions typically carry an emergency epinephrine shot, commonly called an EpiPen. (EpiPen is one brand name; 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.
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 boils down to knowing where the allergens are located and how best to avoid them. For example, 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.
Allergies are common and don’t have life-threatening consequences for most people. Those who run the 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.
Written by: Brian Krans
Medically reviewed by Brenda B. Spriggs, MD, MPH, FACP