I was allergic to cats but now I'm not. Why not?

December 7, 2010 6:39 AM

Once upon a time I was very allergic to cats, but this appears to have gone away. My dog allergy has stuck around though. What mechanism is likely at work for an allergy to simply disappear? Will it come back?
posted by deeper red to Health & Fitness (9 answers total)

I had god awful horrible wannakillyourself allergies to dust/pollen/everythingintheair from about age 18 until my mid 30s. One day they were there, and then one day I noticed they were gone. They haven't come back in any big way since. When I realized they had cleared up I read about how allergies can come and go as you get older.
posted by Blake at 6:57 AM on December 7, 2010

My allergy to cats went away while I was pregnant, and never returned. Doc attributed it to "hormones."
posted by SuperSquirrel at 7:27 AM on December 7, 2010

i used to have reactions to my sister's cats when i would stay at her apartment for any length of time. however, i eventually got my own cat and ended up with both of hers at one point. i'm not sure if my body just built up an immunity, but that's what it seemed like when i first got my cat. if the living space isn't cleaned properly, sometimes i still react a little to other people's cats, but my own have not been a problem.
posted by itsacover at 7:37 AM on December 7, 2010

I developed some rather severe food allergies 4 years ago- after a pretty intense couple of days of testing, I was told that adults (with prior allergies) should be retested for the whole panel of allergens every 7-10 years as allergies evolve as your body matures. Additionally, those tests do create false positives, but at least they can give you an idea of what else could be triggering reactions. Keep in mind that in many cases, each subsequent exposure to the allergen may be more severe. (rash this time... hives the next... then bam you're in the hospital gasping for breath)

Personally I'm hoping that the "OMG YOU WILL DIE if you touch/eat this" allergies I developed will be less DEATH and more just an annoyance in another 5 years, but that's unlikely- I was also told that it is very hard to "grow out of" allergies developed after age 20.

The Mayo clinic (reputable) has a pretty solid set of pages on allergies. Additionally, Late Onset Allergies (or Adult Onset Allergies) are on the rise as a whole in developed countries so there's a bunch of scare mongering news articles about it. (avoid those).
posted by larthegreat at 8:01 AM on December 7, 2010

Is it at all possible this is a cleanliness issue? I had zero problems with my cat growing up, because my mom vacuumed / made me vacuum very regularly. When I visit one particular friend's house, I generally have a reaction because she cleans much less frequently.

Otherwise, everyone else is right, your immune system develops and allergies can change.
posted by momus_window at 10:09 AM on December 7, 2010

Is it possible that you are still allergic to cats, but not allergic to one or two cats that you have recently come into contact with? Sometimes allergies can be triggered less by specific animals, so you can be allergic to cats in general but not your friend Kelly's cat in specific.
posted by rosethorn at 3:36 PM on December 7, 2010

I was coming in to say what rosethorn said. Most cats bother me, but not my best friend's cat. She can (and does!) stick her tail right under my nose and I'm fine.

Conversely, most dogs do not bother my allergies. But my neighbor's dog... within 15 minutes of petting her, I'm sneezing and my eyes are swollen and watering like crazy. We've gone through all the products they use (dog shampoo, flea cream, etc) and other friends use it and I'm not allergic to their dogs.
posted by IndigoRain at 11:40 PM on December 7, 2010

@rosethorn, I've done some testing. We borrowed a cat from a friend for a week and I had no issues. Additionally, we went to the house of a friend with a long-haired cat and again, no issues.

Just 5-10 years ago entering the house of somebody who has a cat would have caused me to start sneezing and get itchy eyes. I could sense in my nose when I was in such a house even if I didn't start sneezing.
posted by deeper red at 12:48 AM on December 9, 2010

My allergies completely vanished one year. Turned out I had prolonged infectious mononucleosis problem ( I thought it was just grad school stress). When that was over my allergies were back in full force. Ever since then I have noticed that my allergies are bad when I have no other health issues. So maybe get a check up and see if your immune system is busy dealing with something else.
posted by srboisvert at 6:43 AM on February 3, 2011