To tell MIL allergic to something in her house?

[Sunsetred]

Whenever I stay over night at my MIL's house I end up with hives. I'm allergic to something in her house, most probably something in the bedroom. It's very strange as I don't normally have any allergies, and I have never had hives or an allergic reaction before.

I am convinced she has mould under the wallpaper and carpets and this is what is causing my hives. She never opens windows and it feels like there's a lot of moisture in the air. The bedding feels damp even. I really want to tell her that I'm getting hives when staying at her house and that she needs to open her bathroom window occasionally and investigate for mould. However, I'm not sure if this would come across as rude? I am worried about my children staying here if it is something like black mould and about my MIL's health and well-being too.

YABU - Don't tell her it's rude to say anything.

YANBU - Tell her about the hives and what might be causing it.

It could be anything, her laundry detergent, softener, fabric sprays, her perfume or plug in air fresheners, if she has pets...etc. Unlikely to be caused by mould, although if she is having issues with damp it would be wise to mention it, purely from the perspective of stopping it getting any worse and affecting her health. If you can afford it, book a private allergy test, if not, maybe start taking a low dose of antihistamines, for example loratadine or cetirizine 10mg when you visit and see your GP, although I'd recommend not visiting at all if you suffer so badly and be honest about why.

Maybe it MIL?

Jokes - yes ask her what washing powder she uses perhaps?

Can you ask her to air the room before you arrive? Also take an antihistamine if you don't already

I would check the laundry detergent first. My MIL used Biological when we only use non-bio and it caused issues with my skin.
Easy fix.

I think it would be rude. Much as I'd be tempted. How often are your children staying there? Probably not enough to do harm even if there is black mould?

@Coucous haha! I had wondered that but she's not actually here on this occasion we're here!

I've just checked laundry detergent and it's a common one which I've used before so unlikely to be that. She has no pets and no plug in air fresheners. Lots of perfume in the room so it could be that but I've never had an issue with perfumes in the past.

The hives are really bad and she saw them when we here before and said they were insect bites because I opened the window in the bedroom. The GP confirmed they were hives when we got home but I haven't told her that. They took ages to disappear.

I've taken an antihistamine!

@MaggieFS we don't stay over night that often but my DD2 does stay here for a few hours a couple of times a week.

I'd take my own sheets (or wash those there) to rule out the bedding (including the possibility she sprays perfumes around). I'd wipe down surfaces too to remove furniture polishes.

Does she have plants in the house. I know someone who is allergic to a plant that flowers open at night.

Does she have any pets you could be allergic to?

For me it was dust mites in a family member's home and I had to tell them as I react terribly and we stay there regularly. It was very awkward, but things are much better there now.

Really you have no idea what could be causing it so accusing her of having a mould ridden home does seem quite rude, yes!