- By Emily Gurnon
When my daughter was two, I took her and her older brother blueberry picking near our hometown of Arcata, Calif. The farm owners weren’t too concerned about children “sampling” the goods. So my kids scarfed plenty of fruit before we got out of there with a full bucket.
The next day, a red rash blanketed my daughter’s torso. She was allergic.
Now that she’s a teenager, the allergy has disappeared. Allergies are funny that way. We often grow out of the ones we had as children.
But — as many of us know all too well — we can also grow into allergies as adults.
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Why Allergies Pop Up In Adulthood
The reasons are not altogether clear, said Dr. Calman Prussin, of the National Institute of Allergy and Infectious Disease’s Laboratory of Allergic Diseases.
In some cases, the level of exposure is not high enough until adulthood. “Essentially, you have to become exposed to the allergen to become allergic,” Prussin said.
That seemed to be what happened to my mother when she was in her 40s.
I received a kitten for my 10th birthday. We had never before had a pet, other than turtles and goldfish. Within a year, my mom developed a severe allergy to Puffy, and we had to give her away (the cat, not my mom). From then on, even a small exposure to cat dander would make her sneeze and wheeze.
Medication can also prompt allergies in adults who didn’t have them previously, Prussin said. Penicillin and other drugs in its class are prime culprits. Another (though technically not an allergy) is reaction to iodine-containing X-ray dyes, which are also used in CT scans. As we age, “you have a lot more chance to be exposed to that,” he said.
Allergies are essentially “a mistake by your immune system,” Prussin said. When faced with allergens, the body should say, “I should not bother with them — they’re not going to hurt me,” he said.
Instead, the immune system goes into fighter mode. “It’s very similar to the immune response we make to worm parasites,” Prussin said.
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Cat allergies, hay fever and some food allergies — especially shellfish — commonly arise in adulthood, he noted.
Shellfish may be one of those things that we get more exposure to as adults. In America, shrimp, clams and oysters are not typical kiddie fare.
We were lucky that our daughter’s reaction to the blueberries was merely a bad rash. Food allergies are potentially deadly, for children and adults.
“For people that have allergies, and specifically food allergies, 25 percent of them will have a near-fatal anaphylaxis at some point in their lives,” said Dr. Kari Nadeau, an immunology researcher at Lucile Packard Children’s Hospital Stanford and the School of Medicine in Palo Alto, Calif. Nadeau will lead a new allergy research center at Stanford that's being funded by a $24 million grant from Sean Parker. The co-founder of the music file-sharing service Napster and founding president of Facebook, Parker has struggled with life-threatening food allergies and asthma since childhood.
Signs of Anaphylaxis
Two or more of the following symptoms, within minutes or hours of exposure to an allergen, are a likely indication of anaphylaxis — a medical emergency, according to the National Institute of Allergy and Infectious Diseases:
- Hives, itching or redness throughout the body
- Swelling of the lips, tongue or back of the throat
- Trouble breathing
- Dizziness or fainting (signs of decline in blood pressure)
- Severe gastrointestinal symptoms, such as cramps, diarrhea or vomiting
If you or another person has these symptoms, use an epinephrine auto-injector, such as the EpiPen, and call 911.
4 Things to Do If You Have Allergies Now
1. Try over-the-counter drugs. Nasal corticosteroids used to be available only with a prescription, but that changed in 2014. They are safe and effective for nasal allergies, Prussin said.
2. Keep your doctor apprised of your allergies. Ask about prescription medications, such as injectable epinephrine, if you have food or bee sting allergies.
3. Pay attention if you have a mild reaction to a food or other allergen. Further exposure down the road could cause a more severe response.
4. Try to stay away from whatever causes your allergies. Ask your doctor about allergy shots (immunotherapy) if you are allergic to a pet and can’t give him or her up.
The Good News: Your Allergies Should Get Better
As we enter our later years, our immune systems aren’t quite as “brisk,” Prussin said. The downside to that is that we are more susceptible to things like shingles, the flu and pneumonia. But that also means that “mistaken” immune response to allergens also quiets down.