How does allergies occur

Foods that commonly cause allergy include peanuts, seafood, dairy products and eggs. Cow's milk allergy in infants may occur and can cause eczema, asthma, colic and stomach upset.

Some people cannot digest lactose milk sugar. Lactose intolerance causes stomach upsets, but should not be confused with allergy. Skin problems that can be triggered by allergy include atopic dermatitis eczema and urticaria hives. Most allergic reactions are mild to moderate, and do not cause major problems. However, a small number of people may experience a severe allergic reaction called anaphylaxis, which requires immediate life saving medication.

Allergens which may cause anaphylaxis include foods, insects and medications. Allergen avoidance or minimisation relies on identifying the cause of the allergy and taking steps to reduce exposure to the allergen. For example, reducing dust mite in the home may help reduce symptoms in people who are allergic to mites. Non-medicated treatments such as saline sprays are used for treating allergic rhinitis and sinusitis. Allergen immunotherapy also known as desensitisation is a long-term treatment which changes the immune system's response to allergens.

It involves the administration of regular, gradually increasing amounts of allergen extracts, by injections or by sublingual tablets, sprays or drops. If you have an allergy see your local pharmacist or doctor. ASCIA resources are based on published literature and expert review, however, they are not intended to replace medical advice. Information for the community about allergic diseases, immunodeficiencies and other immune diseases. See latest edition here Join our mailing list:.

Read more The content provided is for education, communication and information purposes only and is not intended to replace or constitute medical advice or treatments. ASCIA respects your privacy. Read our privacy policy here ASCIA does not endorse products from sponsoring organisations , nor is it influenced by sponsoring organisations with regard to the content of education programs and websites.

This site complies with the HONcode standard for trustworthy health information: verify here. Allergy glossary of terms Anaphylaxis Checklist - Anaphylaxis Anaphylaxis translations Anaphylaxis translations - New Zealand Common myths about allergy and asthma exposed Allergic rhinitis hay fever and sinusitis Allergic rhinitis hay fever and sinusitis Allergic rhinitis hay fever? As the saliva dries, protein particles become airborne and work their way into fabrics in the home.

Pet urine also can cause allergies in the same way when it gets on airborne fur or skin, or when a pet pees in a spot that isn't cleaned. Cockroaches are also a major household allergen, especially in inner cities. Exposure to cockroach-infested buildings may be a major cause of the high rates of asthma in inner-city kids. Cow's milk or cow's milk protein. Most formulas are cow's milk-based. Milk proteins also can be a hidden ingredient in prepared foods. Many kids outgrow milk allergies.

Egg allergy can be a challenge for parents. Eggs are used in many of the foods kids eat — and in many cases they're "hidden" ingredients. Kids tend to outgrow egg allergies as they get older. Fish and shellfish. These allergies are some of the more common adult food allergies and ones that people usually don't outgrow.

Fish and shellfish are from different families of food, so having an allergy to one does not necessarily mean someone will be allergic to the other. Peanuts and tree nuts. Peanut allergies are on the rise, and as are allergies to tree nuts, such as almonds, walnuts, pecans, hazelnuts, and cashews.

Most people do not outgrow peanut or tree nut allergies. Soy allergy is more common among babies than older kids. Many infants who are allergic to cow's milk are also allergic to the protein in soy formulas.

Soy proteins are often a hidden ingredient in prepared foods. Wheat proteins are found in many foods, and some are more obvious than others. Although wheat allergy is often confused with celiac disease , there is a difference. Celiac disease is a sensitivity to gluten found in wheat, rye, and barley. But a wheat allergy can do more than make a person feel ill — like other food allergies, it also can cause a life-threatening reaction. Other Common Allergens Insect allergy.

For most kids, being stung by an insect means swelling, redness, and itching at the site of the bite. But for those with insect venom allergy, an insect sting can cause more serious symptoms. Antibiotics are the most common type of medicines that cause allergic reactions. Many other others, including over-the-counter medicines those you can buy without a prescription , also can cause allergic reactions.

Some cosmetics or laundry detergents can make people break out in hives. Usually, this is because someone has a reaction to the chemicals in these products, though it may not always be an allergic reaction.

Dyes, household cleaners, and pesticides used on lawns or plants also can cause allergic reactions in some people. Airborne Allergy Symptoms Airborne allergens can cause something known as allergic rhinitis , which usually develops by 10 years of age, reaches its peak in the teens or early twenties, and often disappears between the ages of 40 and How Are Allergies Diagnosed?

A skin test can work in one of two ways: A drop of a purified liquid form of the allergen is dropped onto the skin and the area is scratched with a small pricking device.

A small amount of allergen is injected just under the skin. This test stings a little but isn't painful. Airborne Allergies To help kids avoid airborne allergens: Keep family pets out of your child's bedroom. Remove carpets or rugs from your child's room hard floors don't collect dust as much as carpets do. Don't hang heavy drapes and get rid of other items that allow dust to build up. Clean when your child is not in the room. Use special covers to seal pillows and mattresses if your child is allergic to dust mites.

The same situation may occur for people watching others enjoy an endless variety of foods while they must be very selective. Those people who suffer from the incessant symptoms of food or environmental allergies may wonder, why? Have you ever wondered what causes your stuffy nose and sneezing? For allergies, the immune system generates Immunoglobulin E, also known as IgE, to aid in combating your allergy symptoms. IgE is a chemical messenger that travels to cells to relay information that a chemical defense against a foreign invader is needed.

Allergic individuals have high IgE levels against benign environmental exposures such as pollen or dander. Food can also cause high levels of IgE. Normally this is a helpful immune response which can enable your body to respond more quickly.

This is what allows vaccines to work. In allergy, however, this response is magnified, and your repeat exposures cause recurrent overreactions of the immune system. This produces an allergic response that may include sneezing, coughing, sniffling and congestion or increased asthma symptoms.

IgE antibodies are custom made for each type of allergen. This is why you can be allergic to one or two specific foods or pollens and tolerate others without a problem. One factor that increases your chance is your family history. In many cases, allergies first present early in life, during infancy or the toddler years. Most of these allergies will be lifelong concerns, although some can resolve on their own. It is certainly possible to develop allergies in adulthood.

Adult-onset allergies can occur seemingly out of nowhere due to exposure to new allergens in the environment, family history and changes in the immune system. The most common food allergies in adults are peanuts, fish, shellfish such as shrimp, lobster and tree nuts almonds, walnuts, pecans and cashews.

In addition, there is some recent research that indicates avoiding allergens can make it more likely for an individual to develop allergies, because the immune system is unfamiliar with more substances. Adult-onset allergies are those allergy symptoms that manifest later in life.

Typically, if you lived through your 20s and your 30s without any new allergies, the chances of getting adult-onset allergies diminishes. You could have been in contact with said allergen every single day for years with no adverse effects. Now, you have a runny nose, itching eyes and uncontrollable sneezing around that allergen. Say, for instance, you never had pets growing up. Then, your roommate decides to get a dog, and your allergies start going crazy. In other cases, allergies do develop on their own.

You may notice changes suddenly, or monitor a gradual shift in your reaction to a specific substance. Adult onset allergies typically develop differently in different people. We do know there are complex genetic and environmental factors involved. Adults can also present with new-onset environmental allergies. In some cases, the patient may have had a tendency to develop allergies all along, but their environment changed, putting them in more contact with the triggering allergen for example, a new pet in the home.

If you believe you have developed allergies as an adult, avoid any suspected allergens while you are waiting to see your allergist. Your allergist may order some tests such as blood or skin tests to further evaluate your allergies. As many as 50 million adults may get reactions to allergens as well. While more adults have allergies in the United States than children, is there an age group that has it worse?