Any ideas what this is?

[theheartofthematter]

This rash has come up in my DD. She was sent home from school as she has been having bad headaches for the last 24 hours or so and they are making her feel sick and she had a stomach ache. She has had a hot water bottle but that was at about 4pm so I have ruled out a mark from that (and it has a good cover on anyway so I don't think it is connected. The first pic was taken at 6 pm. The second at 7 after an antihistamine. It does seem to be going down but I just don't know what could have caused it and it seemed to go down to that level relatively quickly and has stopped improving.

Honestly it looks like the hot water bottle to me. (Not a medic, but an over-enthusiastic user of boiling hot HWBs).

Have you done the 'glass test' to make sure it fades when pressed?

No clue but if it’s reacting positively to an antihistamine it’s likely an allergic reaction to something. Eaten anything different?

That's the exact rash I get from my hot water bottle (it has a cover) so I'd put money on it being from that

I used to get that rash on the tops of my thighs from putting the laptop on my lap. It would start very red then fade like the second picture over a few hours. If it doesn't go under a glass though, call your gp as it is much better to be sure

That'll be erythema ab fine, caused by the application of direct heat. Also know as chilblains

*Ab Igne (excuse the autocorrect)

I get a very similar mark from resting a hot mug on my stomach

It is the hot water bottle.