Allergies in later life: unexpected allergic reactions and how to find relief

If you’ve never suffered from allergies before, you might assume you never will. But here’s something that can come as a surprise to a lot of people: Allergies can happen at any time.

There are many reasons why you might not develop an allergy until adulthood, but the first one is simply exposure. You need to come into contact with something to be allergic to it.

And sometimes there’s nothing new about an allergy except for how the body reacts. For example, many people spend years being exposed to certain pollens before experiencing allergy symptoms.

What are allergies?

Allergies happen when your body reacts to things that are normally harmless, like pollen, pet dander, dust mites, or certain foods.

When that happens, the immune system mistakenly thinks these substances are dangerous and tries to defend the body. It does this by making special antibodies that tell the immune system to release the chemical histamine.

Histamine is what causes a variety of allergy symptoms and reactions, including a runny or stuffy nose; shortness of breath, coughing or wheezing; a rash, hives, or itchiness; and abdominal pain, nausea or vomiting.

Why do we get allergies?

Good question. The “why?” is still somewhat of a debate in the world of medicine, but allergies appear to be a product of both nature and nurture. And the reasons why allergies are triggered, when they’ll be triggered, and for who, are still not well known.

For example, allergies can run in families. But they don’t necessarily follow a straight line. Say a parent has a spring tree allergy. One child may not inherit it. Another may develop a tree pollen allergy — or instead, the allergy becomes a ragweed allergy in the fall. Allergies can also skip a generation.

Why do allergies seem to suddenly pop up in adults, sometimes well into their golden years?

Allergies can ebb and flow throughout someone’s life, seemingly at random.

Adults who have never had an allergy can suddenly find themselves having an allergic reaction to an allergen that never previously bothered them. (Or, they can find that things that used to cause reactions don’t bother them anymore.)

Risk factors for developing allergies as an adult include:

• Genetics. As mentioned above, allergies can be inherited.
• Severe allergies during childhood. And adults might not suffer from the same allergies they had as kids.
• Weak immune system. Exposure to allergens during a time when your immune system is weak, such as when you’re sick.
• Exposure to new allergens after moving to a new city, home or workplace; exposure to a new pet; or exposure to high levels of an allergen for the first time as an adult.

What are the different types of allergies?

About 10% of U.S. adults have food allergies — and half of those are adult-onset allergies.

Common food allergies

Fish

Shellfish

Nuts

Milk

The most common food allergies in adults include seafood allergies (including fish and shellfish), peanuts and tree nuts (almonds, walnuts, cashews, pecans), and milk.

Is it a coincidence?

Some food allergies can be related to other allergies you’re already aware of. Example: shrimp allergies sometimes go hand in hand with a dust mite allergy. Is it “cross-reactivity” or coincidence? Researchers don’t know.

The same is true for people with allergies to airborne allergens like pollen. A ragweed allergy sufferer, for example, can also experience oral allergies to bananas, watermelon and cantaloupe. And allergies to birch tree pollen can go along with oral reactions to stone fruits like peaches, plums and cherries.

That’s because there are molecular similarities in the substances found in these pairings. Your body sees them as similar allergens and launches a defense against them.

Other factors

Adult-onset food allergies also may be a matter of long-term exposure. Say you’ve never noticed a reaction to a food, and now you find your lips swell after eating it. Maybe you were genetically predisposed to the allergy all along, but it took years of exposure to trigger that response in your immune system.

Another factor can be how food is prepared. Some people with a pollen-fruit syndrome may find that they can eat baked apples, but get an oral rash or mouth itching after eating a raw apple, especially if it isn’t peeled.

If you notice new symptoms of a food allergy, like swelling or itching of your lips, tongue or throat, talk with your doctor.

Pollen, ragweed and grass are some of the most common allergens. New allergic reactions to these and other outdoor allergens can happen after moving to a new region, where you’re exposed to a new ecosystem.

They can also occur if you’ve had a change in medications — more specifically, if you stop taking a certain medication. For example, antihistamines can be prescribed for things like anxiety and insomnia. If you stop taking them, you might begin to feel the effects of seasonal allergies you didn’t know you had.

Pet allergies can develop in adults for several reasons. Maybe the dog you have now sheds more than the dogs you grew up with. Or the cat you adopted is male and you had female cats growing up (researchers say you’re more likely to be allergic to male cats than females). And they might be hopping in bed with you at night.

All these lead to you being exposed to more allergens now (pet dander — skin flakes — and chemicals in the pet’s urine or saliva) than you were in the past.

Wasps, honey bees, yellow jackets and hornets are the most common stinging insects found in the U.S. The first time you’re stung by a bee, wasp or other stinging insect, although it hurts like heck, you probably won’t have much of a reaction allergy-wise. Even though your body may begin its defense against the sting, you probably won’t feel any symptoms of an allergic reaction.

Over multiple stings, however, your body could simply reach its threshold to an allergic reaction. The allergy may have been there all along but you didn’t know it.

Certain medications (most commonly penicillin antibiotics) can cause allergy symptoms in some people. Symptoms can include hives, itching, swelling, wheezing and anaphylaxis (a potentially life-threatening allergic reaction that involves multiple body systems).

Do allergies ever go away?

Most allergies can’t be cured (although some can fade over time). But effective treatments can help provide relief and control the symptoms.

If you notice a potentially new allergy, see your doctor to find out for sure, and to discuss treatment options.