Why allergies exist

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? Research that appeared in a article at MassGeneral Hospital for Children in Massachusetts suggests that adults may be the most at risk for intense, serious symptoms.

Adult behaviors such as taking certain medications like ACE inhibitors, beta-blockers, and NSAIDs, even aspirin and drinking alcohol may increase risk for severe anaphylaxis. Exercise and having asthma can also increase reaction severity.

Of course, young children who cannot communicate symptoms can also have severe reactions which go unnoticed and progress to dangerous levels. A severe allergic reaction, which can be triggered by foods or venom insect stings , is called anaphylaxis. This is a life-threatening emergency condition in which the patient goes into shock, cannot breathe, and may have vomiting, nausea, and skin rashes. Anaphylaxis can occur instantaneously or sometimes minutes after eating an allergen or being stung.

Epinephrine can control cases of anaphylaxis that are caught immediately. The longer the patient goes without treatment, the greater the likelihood that death can occur. For this reason patients with a history of severe anaphylaxis are encouraged to always have an in date epinephrine injector available. In fact, food comprised nearly 50 percent of these allergies! Which foods triggered the most allergies?

The point of these works was to figure out why allergies exist at all, so we are still far from providing therapies based on these findings, Medzhitov says. Dina Fine Maron, formerly an associate editor at Scientific American , is now a wildlife trade investigative reporter at National Geographic. Already a subscriber?

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Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? Create Account See Subscription Options. Continue reading with a Scientific American subscription. Subscribe Now You may cancel at any time. In the early s that began to change. In Clemens von Pirquet, an Austrian pediatrician, noticed that patients vaccinated for smallpox using horse serum reacted quickly and severely to a second dose. Pirquet correctly deduced that the symptoms of what he called serum sickness were being caused by the immune system producing antibodies to fight antigens, or foreign substances contained in the serum.

In , he coined a new term for this antibody-antigen interaction: allergy. Over the next few years this hypersensitive reaction of the immune system was proposed as the cause of hay fever, asthma, some skin diseases, and anaphylaxis—the extreme whole-body allergic reaction that can cause death.

After the Second World War, the term allergy was being applied to many conditions, including reactions to synthetic chemicals such as cosmetics, and to some common foods. As early as the first century A. In an important breakthrough, exhaustive studies of cases previously dismissed as medical anomalies were demonstrated to be food allergies. The floodgates opened, and as diagnoses surged many medical practitioners derided food allergies as a passing fad. Meanwhile, the production of drugs to treat allergies accelerated.

In , the steroid corticosteroid was successfully used to reduce the inflammation in asthma attacks, and specific anti-allergy products were developed, such as non-biological washing powder that answered growing fears about the enzymes in biological soaps.

Food labeling also became widespread and warnings about potential allergies began to appear. These are found in some of the most sensitive parts of the body, including the skin, blood vessels, and respiratory system.