Adult-Onset Allergies

Causes, Symptoms, Prevention, and Treatment Methods

Although many people develop allergies when they are young, you can also develop allergies in adulthood. Allergies are an overreaction of the immune system to a normally harmless substance (an allergen).

Read more about adult-onset allergies, what causes them to develop, their symptoms, and prevention and treatment methods.

adult onset allergies - man covering nose with tissue

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What Are Adult-Onset Allergies?

Adult-onset allergies are allergies that develop in your adulthood. The allergy could start from young adulthood (in your 20s) to older age (in your 70s or 80s).

Although allergies are more common in children, adults may also experience allergies. A 2019 study reported that half of the adults with food allergies had at least one of their food allergies appear in adulthood.

One of the peculiar things about adult-onset allergies is that they are very unpredictable. You can be perfectly fine without allergies, only to wake up and discover you are one of the 50 million Americans with allergies.

Sometimes you may have lived with a certain kind of allergen all your life with no issues, only to suddenly develop symptoms caused by the allergen. 


Researchers have not been able to pinpoint the exact cause of adult-onset allergies. However, a few things that may be responsible are:

  • Family history: Adults who have a family history of a particular allergy may develop an allergic reaction later in life.
  • Little exposure while growing up: Some people grow up in extremely clean environments, which prevents their bodies from getting familiar with common germs and substances. Hence, the body may overreact when finally coming into contact with usually harmless substances (allergens).
  • Antibiotics overuse in childhood: Various studies claim that early use or overuse of antibiotics in children, particularly infants, could increase the chances of developing allergies in childhood or adulthood.
  • Moving to a new place: It is possible that relocating to somewhere with different allergens could cause your body to react because it is not used to them.
  • Stress: If you experience a certain amount of stress, it can enhance allergic reactions.

How Common Are Adult-Onset Allergies?

Although allergies often begin during childhood, adult-onset allergies are also common. Of the more than 10% of Americans diagnosed with food allergies, about half of these are diagnosed in adulthood.

Common causes of food allergies in adults include shellfish (most common), milk, wheat, tree nuts, and soy.

Common causes of respiratory allergies in adults include pollen, dust mites, mold, and animal dander.

Signs and Symptoms

The best way to tell if you are experiencing adult-onset allergies is by noticing the signs and symptoms. A few signs to look out for include:

  • Itchy eyes, throat, or skin
  • Runny or stuffy nose
  • Watery eyes
  • Excessive sneezing

Food allergy symptoms may also include:

  • Hives
  • Stomach cramps, vomiting, or diarrhea
  • Swelling

In adults, symptoms may be more severe with cases of anaphylaxis (a life-threatening allergic reaction), especially if the adult was previously exposed to that allergen.

Seek immediate emergency help if you experience any of these anaphylaxis symptoms:

  • Throat tightness or hoarseness
  • Trouble breathing or wheezing
  • Tingling in hands, feet, lips, or scalp

Allergy Management and Prevention

To manage your allergies and prevent an allergic reaction:

  • Avoid allergens, if possible: People who are allergic to pollen should stay indoors during higher pollen counts. Those allergic to dust or pets should live in a clean environment and avoid pet dander. If you have a food allergy, learn to read food labels and use care when dining away from home.
  • Take allergy medications: Allergy medications come in different forms, such as tablets, sprays, or even injections. Antihistamines are commonly used to treat allergies like allergic rhinitis or conjunctivitis. Your doctor may also recommend steroid creams.
  • Consider taking allergy shots (immunotherapy): If other medications don’t work, your allergist may consider immunotherapy, commonly known as allergy shots. This method works by administering injections that contain small amounts of the allergens your body reacts to. Over time, your body will become immune to the allergens.

When to Seek Professional Treatment

If allergy symptoms are affecting your quality of life, see your healthcare professional to have the allergy diagnosed and get the proper treatment and advice on reducing your exposure.

Seek medical attention immediately if allergy medications don’t stop allergic reactions. Also, reach out to your doctor if you start reacting to any new drug prescribed to treat allergies.

Rush to the emergency department in life-threatening situations like anaphylaxis. If you have an epinephrine auto-injector, use it immediately if you sense a severe allergic reaction. You should still visit the emergency ward after the shot and schedule a visit with your doctor for further evaluation.


Adult-onset allergies are common allergies that develop when you’re an adult. They could start at any time from when you’re a young adult through to old age.

Common causes of these sudden allergic reactions are related to family history, little exposure in childhood, antibiotic overuse, moving to a new place, and stress.

Ways to manage and prevent these allergies include avoiding the allergens, taking medications, and immunotherapy. In severe cases, visit the nearest emergency department for medical attention.

A Word From Verywell

Adult-onset allergies can come on when you’re not expecting them, but that doesn’t make them dangerous. Keeping yourself updated and taking note of what you may be allergic to can help you keep them in check. Nevertheless, call 911 if you notice anything out of control or experience severe attacks.

Frequently Asked Questions

  • Can you cure adult-onset allergies?

    Yes, you can. When you discover these allergies, you might be alarmed. But after you find out what you’re allergic to, you can keep them under control.

  • At what age do adult-onset allergies develop?

    Adults can develop adult-onset allergies as early as their 20s or 30s to as old as their 70s or 80s.

  • What is the most common adult-onset allergy?

    Food allergies are the most common adult-onset allergy, with about 13.3% for shellfish, 6% for milk, 5.6% for wheat, 4.8% for tree nuts, and 3.9% for soy.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  6. De Martinis M, Sirufo MM, Ginaldi L. Allergy and aging: an old/new emerging health issue. Aging Dis. 2017;8(2):162-175. doi:10.14336/AD.2016.0831

  7. American College of Allergy, Asthma, and Immunology. Food allergy.

  8. American Academy of Allergy, Asthma & Immunology. Food allergy.

  9. MedlinePlus. Allergic reactions.

  10. Warren C, Stankey C, Jiang J, Blumenstock J, Smith B, Gupta R. Prevalence, severity, and distribution of adult-onset food allergy. Annals of Allergy, Asthma & Immunology. 2018;121(5):S14. doi:10.1016/j.anai.2018.09.041

Additional Reading

By Margaret Etudo
Margaret Etudo is a health writing expert with extensive experience in simplifying complex health-based information for the public on topics, like respiratory health, mental health and sexual health.