what causes sudden allergies in adults
Can you develop allergies as an adult? Learn about what causes sudden adult-onset allergies and how you can recognize the symptoms

Although we often think of allergies as starting in childhood, the reality is that many adults find themselves suddenly dealing with allergies for the first time later in life. Recent studies have found that almost 50% of adults with food allergies developed at least one of their allergies in adulthood. 

So if you’ve never had a problem with pollen or other allergens before, it’s possible to acquire adult-onset allergies. Researchers aren’t sure exactly what causes an immune system to suddenly react to an allergen, but causes may include the following:

  • Family history of allergies: Allergies seem to have a genetic component, which may only develop at certain ages or due to certain types of exposure. You may be at a higher risk of developing an allergy as an adult if your first-degree family members have allergies as well.
  • Not enough exposure in childhood: Your immune system needs to be exposed to certain germs in order to develop defenses against them. If you weren’t exposed to many germs in childhood due to overuse of cleaning chemicals or antibacterial products in your home, you may not have had enough exposure to trigger an allergic reaction.
  • Overuse of antibiotics during childhood: Some studies suggest this could make you more likely to develop allergies as an adult.
  • Change in environment: Moving to a new geographical area with different plants, pollutants, or weather can cause you to be exposed to allergens that you weren’t exposed to before.
  • Infections or stressful events: You may experience adult-onset allergies after your body has been through physical or emotional stress, such as after:
    • Throat infection caused by streptococci bacteria
    • Serious illness or surgery
    • Menopause
    • Bereavement or divorce

Unfortunately, the reason for these immune system triggers is unknown, but it is not uncommon. Although some people remain undiagnosed for decades (perhaps with milder, less frustrating symptoms that suddenly escalate), many develop full-blown allergies as adults.

What are symptoms of adult-onset allergies?

When it comes to allergies, symptoms tend to get worse over time, and some may even be life-threatening. A few common signs and symptoms you need to watch out for include:

  • Runny nose or nasal congestion: May be triggered by an airborne allergen such as pollen, dust, or pet dander
  • Itchy, swollen eyes: May be caused by allergens entering the eyes, such as pollen or ingredients in a new eye cream
  • Red and white, raised rash: Also called urticaria, looks like nettle rash and disappears after 20 minutes, and almost always a sign that you have had an allergic reaction to something you have eaten
  • Swelling of the lips, tongue, and face: Rarest but most dangerous kind of allergic reaction that can come on very quickly
    • May be the result of eating a certain food (such as peanuts or shellfish), taking certain medication, or a wasp sting
    • May quickly develop into an anaphylactic shock (in which the throat and airways swell and breathing becomes difficult) and be deadly, therefore requiring emergency medical attention

What are treatment options for sudden adult-onset allergies?

On the bright side, allergic symptoms are rarely dangerous. There are several treatments that can help, and many of them are available over-the-counter.

Your doctor may want to do an allergy skin test before confirming a diagnosis. Depending on your diagnosis and severity of symptoms, treatment options may include:

  • Finding and avoiding known allergens
  • Taking antihistamines
  • Using nasal sprays or decongestants
  • Carrying an EpiPen at all times (if you have a severe allergy that puts you at risk of anaphylactic shock)
  • Allergy shots or immunotherapy (if your symptoms do not improve with other treatment methods)

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Common Allergies: Symptoms and Signs See Slideshow

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Medically Reviewed on 7/26/2021
References
Donovan J. Adult-Onset Allergies. WebMD. https://www.webmd.com/allergies/features/adult-onset-allergies

De Martinis M, Sirufo MM, Ginaldi L. Allergy and Aging: An Old/New Emerging Health Issue. Aging Dis. 2017;8(2):162-175. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5362176/