You grew up pretty much allergy-free, and suddenly you have developed an allergy. How did that happen?

Most people who are diagnosed with allergies as adults probably had an allergic episode earlier in life that they don’t remember.

Those lucky enough to skate through childhood and adolescence without itchy, watery eyes aren’t immune from allergies for life. Developing adult-onset allergies — from seasonal allergies to food allergies — is possible no matter how old you are.

Allergies develop when your immune system mistakenly identifies a substance such as pollen, mold, animal dander, or food as harmful. That substance is referred to as an allergen. The allergen stimulates immune system cells to release certain chemicals, such as histamine, which then lead to allergy symptoms.

Depending on the allergen, allergy symptoms can involve the nasal passages, eyes, sinuses, airways, skin, and digestive system. Reactions can vary from mild to severe and, in some cases, cause anaphylaxis, a life-threatening condition.

Why Allergies Now?

There’s a lot experts still don’t know about allergies, including what triggers them. They do know, however, that the prevalence of allergic rhinitis, also called hay fever, is increasing in the United States and around the world.

Most theories as to why allergy symptoms have increased focus on “higher concentrations of airborne pollutants, rising dust mite populations, less ventilation in homes and offices, dietary factors, and sedentary lifestyles,” says Deborah Pockross, MD, a physician at Kenilworth Medical Associates in Kenilworth, Illinois, and staff doctor at Northshore University Health System in Evanston.

Another theory is the so-called hygiene hypothesis — meaning “a more sanitary environment [and less exposure to bacteria] increases susceptibility to allergic disease by suppressing the natural development of the immune system,” Dr. Pockross explains. In other words, our living conditions and food are so clean they don’t offer our immune systems enough to do, so our systems overreact to allergens instead.

Who Is at Risk for Adult-Onset Allergies?

Most people who are diagnosed with allergies as adults probably had an allergic episode earlier in life that they don’t remember. Often allergies follow a predictable course: eczema and food allergies in babies and toddlers, then hay fever symptoms in mid-to-late childhood. Allergy symptoms may fade during the teen years, only to return when you’re an adult.

Some people, however, do experience allergy symptoms for the first time in adulthood. This most often happens in your twenties, thirties, and forties rather than in later years. “As we age, our immune system does weaken — that is why more seniors get pneumonia than 20-year-olds,” says Anthony J. Weido, MD, president of Allergy & Asthma Associates in Houston, Texas, and the Gulf Coast area. “As the immune system weakens, the hyper-allergic reaction also weakens,” he says.

Any type of allergy can occur in adulthood, including hay fever, pet allergies, and dust mite and mold allergies as well as insect bite, drug, and food allergies. Again, experts aren’t entirely sure why this happens, but theories include:

  • being exposed to allergens when the immune system is weakened, such as during an illness or pregnancy
  • not being exposed to a high enough level of the allergen as a child but reaching that threshold in adulthood
  • moving to a new location with different trees, plants, and grasses
  • getting a pet



Managing Allergy Symptoms

If you’re bothered by mild allergy symptoms from hay fever and the like, it’s fine to try over-the-counter antihistamines. If this doesn’t help, consult your doctor to rule out other conditions and possibly get a referral to a specialist. An allergy expert can help determine specific triggers, suggest ways to avoid them, and perhaps offer medications.

If you suspect you have a food allergy, take it very seriously, as it can be life-threatening. Be sure to work closely with a board-certified allergist who will teach you about avoiding unexpected sources of the food and managing your allergy symptoms.

Allergies can be unpleasant no matter how young or old you are, but your medical team can help you identify your allergy triggers and find solutions.


By Kristen Stewart, medically reviewed by Niya Jones, MD, MPH

Source: everydayhealth, adapted by AMR Care Group