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Causes of Adult-Onset Allergies

Why Sudden Allergies in Adulthood?

Many people live through childhood sleeping with their pet kitties on their pillows, rolling around on dust filled carpets, and collecting flowers and weeds to give to their moms. They do this without a sneeze or sniffle. Those same carefree kids grow up and when they hit their 20s, they suddenly develop allergies to all those things. What gives?

Allergies can develop at any age, and its prevalence in adults is rising. It's known as Adult-Onset Allergies and there are many theories as to why this happens. The most accepted reason is that nowadays babies' developing immune systems are not exposed to as many viruses, bacterium, and allergens as in the past due to wide use of antibiotics, vaccinations, cleaner food and water supply, better living conditions, and germ-a-phobe parents who don't let their kids roll around in dirt. When immune systems aren't faced with dust, pollen, and mold, they don't fully develop the ability to combat those allergens in the future. So in a way, being too careful and being protected against such allergens can actually cause children's immune systems to develop in an unbalanced way, which can make them hypersensitive to seemingly harmless substances in the future.

Allergies can also develop if you are exposed to allergens when your immune system is weakened. That's why pregnant women often develop allergies after they give birth.

Could your family history be to blame for allergies too? To find out


Genetics can definitely play a role in developing allergies as an adult as well. Allergies to specific allergens are not necessarily inherited, but the general tendency to develop allergies can be traced back to your family. If one of your parents has allergies, then you have a one in three chance of developing allergies too.

Your age also has something to do with developing allergies. Since repeated exposure to certain allergens can cause an allergic reaction, it makes sense to develop allergies when you're older, as you've had more time to be in contact with dust, dander, mold, and pollen.

I guess I should be grateful that I lived without allergies for most of my life, but I get the sniffles now when all the flowers start to bloom. What about you? Are you all of a sudden allergic to your pet or do you get a runny nose as soon as the pollen count climbs?


ksn117 ksn117 4 years
Since 24, I've now lactose intolerant, allergic to hazelnuts, almonds, walnuts, cashews, kiwi, pineapple and Secret deodorant. 'Tis awesome. I was a rough n' tumble kid so I don't agree with that theory of why they developed though.
bluegirl232 bluegirl232 4 years
In my late teens I was severely lactose intolerant. I also became allergic to long hair cats & dogs. When I was 22 I developed a severe case of chronic hives. The hives were so bad that I had to take steroids every day for 2 years to avoid being hospitalized. My allergist was not able to pinpoint what caused the onset or what continued to cause it, only that I had a peanut allergy. I never really ate any peanuts anyway. Those 2 years of my life were miserable & it was so bad and painful. Finally I was able to ween myself off of the steroids & control the hives with a daily dose of antihistamines. Trust me I've tried tons & tons of antihistamines, and I still have daily issues with my sinuses. About a year ago I also developed an allergy to eggs. I can't tolerate anything with eggs period without being ill, even processed foods. It is very frustrating & although it sucks I'm so grateful that I don't have the severe hives anymore. I still get a few every now and then but they are tolerable. I just wish they could figure out what is going on with me.
jazmcfresh jazmcfresh 5 years
I used to always eat apples, drink apple juice and have nuts in my food (peanuts, walnuts etc.) but now when i have those foods i have a minor reaction to them.
Scott2532413 Scott2532413 5 years
I wonder if working in a cleanroom for 20+ years would have anything to do with it??  I have developed allergies to sunflower seeds, almonds and some other foods. I am now having to get surgery for polyps in my sinuses....
rebelrebel1 rebelrebel1 5 years
I think Im allergic to my dog all the sudden- developed breathing problems mostly when I sleep and she's next to me on the bed.....and Ive had her for 10 years now with no problems! 36 years old.
Marilyn03 Marilyn03 8 years
I am 45 and am suddenly very allergic to grass, tree and weed pollen. Full on terribly itchy eyes, runny nose, stuffed up nose, itchy nose, itchy roof of mouth and couphing sometimes. Not a cold, that is how I react to pollens as of Feb 09. Its awful.
emma- emma- 9 years
i think i'm becoming allergic to dairy products. i hate it because i truly love everything dairy. Luckily I'm finding some good soy alternatives. I've also been recommended goat milk...we'll see how that goes.
freegracefrom freegracefrom 9 years
This happened to me too. Once I hit my twenties, I started having major sinus problems (probably due to allergies)... just out of nowhere. So frustrating.
kristyrk kristyrk 9 years
This is so funny that you posted this! I grew up having allergies ALL THE TIME when I was a kid. I moved to Seattle for 3 years and it was like a vacation - not a single seasonal allergy! But here I am back in California and went to my aunts house for Easter and BAM, I had an allergy attack like no other. So weird.
ASpoonfulofSugar ASpoonfulofSugar 9 years
Dude, where's my comment? Basically said that I have allergies all year and am miserable. Boo, allergies.
ASpoonfulofSugar ASpoonfulofSugar 9 years
<-- has allergies and is miserable all year. They definitely got worse in my 20s. Plus, I moved to a warmed climate last fall, and with the milder weather and plant growth later into winter and earlier in the spring, I can barely sleep. My sympathies with you all.
AutumnLove AutumnLove 9 years
I'm so glad it's not only me. I developed an allergy to citrus at 20 and I loved OJ so much. I also developed allergies to pollen and most antibiotics.
burgundyy burgundyy 9 years
im 20 and i think i just developed allergies this year...not fun!
Melo-D Melo-D 9 years
This happened to me but I know that it's genetic for me. My oldest brother is the one to have all the allergies from the beginning. I developed allergies to tree pollen two years ago. Also, the biggest thing is people don't understand that pollen levels have gotten higher over the last 2 years. This is something I truly believe the pharmaceutical companies have trended for a long time since multiple prescription allergy medicines have hit the shelves as OTC meds over the last few years. But that's just me :). If this has happened to you, I would suggest tracking when your allergies hit. If it's seasonal, note what season and use It is wonderful at tracking the levels. If you want to pin point the exact allergen, you might want to get tested. I highly suggest that if you have extreme reactions. Spring allergies like me? It's most likely tree pollen.
designergirl designergirl 9 years
It's funny that there's a post today because this year I have become pretty allergic to oak pollen. It's gotten so bad that I'm going to see an allergist. Francoisehardy, I'm pretty allergic to dairy, but I can still eat Fage yogurt everyday because it's low in lactose.
Spectra Spectra 9 years
Working in a lab, I developed an allergy to latex from the gloves I always have to wear. I have sensitive skin anyways, so I kind of knew I was a candidate for it. Luckily, I got my boss to order me nitrile gloves to wear instead and they don't give me a rash.
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