An Overview of Allergies By Pat Bass, MD | Reviewed by a board-certified physician Updated September 09, 2016 Print To most people, hearing "allergies" sounds harmless, but they are, in fact, among the most common reasons people visit the doctor. Depending on where you live, you can have symptoms year round, and when care is not sought, in some cases, they can even lead to life-threatening symptoms.Take a look at common allergy symptoms.What Are Allergies?Allergies are very common, but do you really know what they are? Allergies are basically an abnormal immune system response against normally harmless substances. If you do not have allergies, exposure to a substance does not lead to the development of any allergic symptoms. However, the allergic person’s body reacts by releasing certain chemicals in response to the substance that ultimately leads to the development of symptoms.Allergens are the substances that lead to the development of allergy symptoms. Article Sick Building Syndrome Explained Article Flooding and Water Damage Can Trigger a Mold Allergy These include things like:pollenslatexmoldsanimal danderdust mitescertain foodscertain medicationsSensitization is a process where your immune system is exposed enough times to certain allergens that your body begins to make allergic antibodies to that particular substance. You do not develop symptoms the first time you’re exposed to an allergen in most cases, but with later exposures. Exposure leads your body to begin making allergic antibodies or IgE against these different allergens. Re-exposure of the allergen leads to the allergen binding to IgE cells and a cascade of events that ultimately result in the development of symptoms. The allergy symptoms you experience depend somewhat on how you are exposed to allergens. Allergens that travel through the air and enter your body through breathing are more likely to cause respiratory and nasal symptoms, while allergens that you would ingest may lead to gastrointestinal or systemic symptoms.Some allergens lead to minor, annoying symptoms, such as a runny nose. Other allergens can lead to severe symptoms, such as swelling of the neck and wheezing.Top 9 Things to Know About AllergiesAllergies are different for different people. Why some people develop allergies to particular substances and others do not is unknown. Allergies sometimes run in families, and other times there will be no family history in someone with severe allergy symptoms. While allergies more commonly occur in childhood, you can develop them at any time in your life.Avoid exposure. If you want to prevent allergies the best thing that you can do is to avoid exposure. Strategies to avoid allergens will depend on the particular type of allergen. For example, you may not think about dust on the ceiling fan making your allergies worse, but you can collect significant amounts of dust that is spread into the air you are breathing every time it is turned on. Likewise, you can do a number of things to avoid exposure to pollens such as keeping your windows closed to prevent pollen from coming into your home, staying indoors when pollen counts are high, and machine drying your clothes so as not to collect pollen when hanging to dry. Article How to Treat Seasonal Allergies Article How to Have an Allergy-Free Camping Trip Prevent the development of allergies. There are number of things that you can do to prevent the development of allergies. Early introduction of foods (before 4 months of age) has been associated with the development of allergies. As a result some have recommended the controversial advice of exclusive breastfeeding. While avoiding allergenic foods in pregnancy does not appear to prevent allergies after birth, breastfeeding mothers may be advised to avoid foods that are allergenic (cow’s milk, eggs, fish, peanuts, and soy proteins) to decrease the risk of atopic dermatitis in children. This can be very difficult for moms and is likely to benefit only those babies at high risk of developing allergies. Generally, the later that you introduce highly allergenic foods into a child’s diet, the less risk they have for the development of allergies.Don’t believe everything you read. You may read about a number different studies that state taking certain vitamins like A, C, and E and selenium will help prevent allergies in the future. However, these studies do not demonstrate any decreases in allergic symptoms consistently over time. The only dietary benefit in the protection against allergic disease is that of omega–3 polyunsaturated fatty acids—those that are found in fish. Severe allergic reactions. Allergic reactions are different from allergy symptoms. An allergic reaction is a medical emergency. This can be a life-threatening reaction most commonly to foods, insect stings, medications, and latex. Symptoms can include flushing, feelings of lightheadedness, shortness of breath, neck swelling or throat tightness, anxiety, cramping, pain, rash, vomiting, or diarrhea. This is often referred to as anaphylaxis and requires immediate medical treatment. If you have ever had a severe allergic reaction, you may want to get an EpiPen and a medical alert bracelet to let others know that you have a serious allergy.Atopic dermatitis. This skin condition is commonly the first sign that parents might see in a child that’s prone to allergies. The location of the rash is different in young children compared to older ones, but it's characterized by itching and scratching of affected areas.When food leads to allergies. Parents usually become suspicious of a food allergy because children develop symptoms such as hives or swelling, itching, or redness that results after eating a particular food. If you’re concerned about a food allergy you should consider seeing your doctor for an EpiPen and referral for allergy testing. Continued or repeated exposure can lead to a severe allergic reaction or anaphylaxis. Article Pollen Counts Can Help People Know When They Could Have Allergies Article What to Know About Tree Pollen Allergy Nasal allergies. The itchy nose, sneezing, watery eyes, and nasal congestion is referred to as allergic rhinitis. You might also have dark circles under your eyes that your doctor refers to as “allergic shiners” or the “allergic salute”—a line on the nasal bridge from rubbing your nose.The link between allergies and asthma. Coughing, wheezing, shortness of breath, and chest tightness are all symptoms of asthma. Allergies can be seen as a cause of asthma or, in some instances, a trigger that makes asthma worse. Either way, if you have asthma symptoms you may want to discuss with your doctor if allergies could be making them worse.If You’re Recently Diagnosed With AllergiesIn general, patients with allergies need to avoid anything that leads to irritation and allergy symptoms. By being aware of your allergy triggers and taking steps to avoid them, you will be much less likely to have symptoms or allergic reactions.This is not always as easy as it sounds. You may want to consider an allergy diary where you document frequency, severity, and location when you develop allergy symptoms. This may help you identify unknown allergens that you were not aware of.There are a number of simple precautions that you can take to help in preventing allergy symptoms, including:When you come inside from outdoors changing your clothes allows you to avoid continuous exposure to any allergens that may have attached to your clothes.Consider going shoeless—this will prevent you from tracking allergens throughout your house.Wash hair before bed—this will prevent pollen and other allergens from getting onto your pillow.Recirculate air in your car instead of using the vent to decrease allergen exposure.Changing out the filter in your air conditioner also decreases your exposure to pollens. Filters should be changed by manufacturers' recommendations.Living With AllergiesFor very mild allergy symptoms, over-the-counter antihistamines may be all the treatment that is needed. However, be careful as some antihistamines can cause a significant amount of sedation.You might also try a saline rinse or spray. This washes allergens out of your nose and provides you with relief of symptoms. Many patients like saline sprays because, unlike other nasal sprays and medications, they can be used as much and as frequently as you would like.Many patients with newly diagnosed allergies sometimes feel that they can never go outside. However, if you have good treatment you should not have to totally avoid the outdoors. If over-the-counter medications are not providing you allergy relief, talk with your doctor about prescription medications to address your allergy symptoms. Your doctor may also want to consider allergy testing.If you do start taking a prescription medication, make sure you take it as prescribed. Many times medication is less effective because patients take medication incorrectly or suffer side effects because they take too much.Questions to Ask Your Doctor About AllergiesCould this be something else other than allergies? If you have done all of the things that your doctors asked or you continue to develop symptoms on treatment, it may be that you have another disease or condition that has allergy-like symptoms but isn’t really an allergy. Ask your doctor what other conditions might lead to your symptoms.What are my triggers? As mentioned above, one of the key treatments for allergy symptoms is avoiding the allergens that lead to symptoms. If you cannot identify your allergy triggers, you will have a more difficult time controlling your allergies.Can I try complementary or alternative treatments? Complementary and alternative medicine is increasingly being used by patients—often without discussing with their doctor. This can sometimes lead to dangerous interactions with other treatment medications or therapies. Most doctors are not opposed to complementary or alternative treatments for allergies, but your doctors do need to know that you’re on them or want to try them. Talk with your doctor before initiating any complimentary or alternative allergy treatment.Will I have to take medication? For many allergies, over-the-counter treatments or lifestyle modifications may be sufficient. However, if you continue to have allergy symptoms you may benefit from prescription medication.How do I take my medicine? It is very important that you understand the dose, frequency, and route of your medication. A medication that you need to spray into your nose may be ineffective and harmful if sprayed on to different parts of the body.How can I learn more? Your doctor is a tremendous source of information about allergies. Ask your doctor for an information prescription that lets you know great places where you can get more information and educate yourself.How often will I need to see you? Many times patients obtain a diagnosis, begin a treatment, but then are lost to follow up. Make sure you have an idea how often you need to see your doctor.A Word From VerywellManaging allergies can be very frustrating. It may seem like a difficult task to avoid triggers and manage a complicated treatment regimen. By developing a trusting and communicative relationship with your healthcare team, you can develop a treatment regimen that is manageable and also lessen the impact of allergies on your life. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit View Article Sources Beltrani VS, Bernstein IL, Cohen DE, Fonacier L. Contact Dermatitis: A Practice Parameter. Ann Allergy Asthma Immunol. 2006;97:S1-38. Practice Parameters for Allergy Diagnostic Testing. Ann Allergy Asthma Immunol. 1995; 75(6): 543–625.