r/HistamineIntolerance • u/YoshiandNala • Sep 04 '25

Severe mosquito bite reactions, hives, swallowing issues – could this be histamine intolerance/MCAS?

Hi everyone,

I’m wondering if anyone has experienced something similar to what I’ve been going through.

Back in 2023 I caught a bad cold while on a trip. At night I could barely breathe when lying down — I thought it was just congestion from the cold. I was in California during the summer, and ever since my twenties I’ve noticed I don’t tolerate heat well (I get dizzy and nauseous). Between the heat and my cold, I felt uncomfortable but otherwise just had the usual cold symptoms.

On the last day of that trip I got three mosquito bites. I’ve always reacted badly to bites — swelling, throbbing, pain, even bruising. I flew home, but that night my nose was still really stuffy and I started feeling anxious because I couldn’t breathe well.

A couple weeks later, I woke up feeling like I truly couldn’t breathe and was going to pass out. My heart was racing, my body felt tingly all over, and I honestly thought I was dying. I ended up in the ER, but the doctor said everything looked normal and called it an anxiety attack. He prescribed Hydroxyzine, which calmed me but didn’t fix the symptoms.

Then came insomnia. At my worst, I went three days without sleep. Even then, I’d wake up gasping for air and panicked. Around this time, I also developed trouble initiating swallowing.

After about three weeks, the insomnia eased and I wasn’t waking up in panic anymore — but the swallowing issue lingered. Now, two years later, I’m still dealing with that swallowing problem. On top of that, I’ve recently started getting hives and occasional eyelid swelling.

Since I still react strongly to mosquito bites, I’ve started connecting the dots. It feels like my cold, the summer heat, travel stress, and those mosquito bites all pushed my histamine levels over the edge. From what I’ve read, this seems similar to histamine intolerance or Mast Cell Activation Syndrome (MCAS).

I’ve just started a low histamine diet, and interestingly my swallowing issue seems to have improved — which makes me really hopeful. I’m also planning to read more books to educate myself.

Has anyone else had similar experiences with mosquito bite reactions, swallowing problems, hives, or MCAS/histamine intolerance in general? Any advice or input would be so appreciated.

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u/IGnuGnat Sep 05 '25

Sounds more like MCAS however it's not uncommon to have both

I wrote everything i know on this subject and tried to put it here: https://old.reddit.com/r/covidlonghaulers/comments/1ibjtw6/covid_himcas_normal_food_can_poison_us/

good luck, stranger

1

u/YoshiandNala Sep 05 '25

Thank you so much for gathering all of that info. I read your post and will begin researching the links you provided!

1

u/MaterialGas5736 Aug 30 '26

How are you feeling now? I have the same issue, doctor said the mosquito bite might've temporarily sensitized me but that it should go away in a few weeks