Sudden angry red rash with raised white patches (like nettle rash) and hot to touch

[Ripeberry]

Went to visit our mother in law when DD2 came up in an angry red rash on odd areas of her body, 3 patches on her back, one big one on her knee, foot, one hand, one cheek and one her her tummy.
They are hot to the touch and she says they only hurt or itch when water is put on them.
She has NEVER had this before and in the space of 10 minutes they came up.
The only thing that he had been doing was rolling around the sofa, but how would it affect the parts covered by clothing?
Within 2 hours the patch on her cheek has totally gone and the others are fadding, but the knee one is still angry looking.
Is it an allergy or some virus?
She is very well in herself otherwise.

Sounds like an allergic reaction to something.

Not a leather sofa is it?

No, not leather, fabric. She's been on it before. I'll keep an eye on it. If its still there tomorrow then off to the GP!

Sounds like "Hives".Did she eat or drink anything? Or touch anything in the garden maybe?

See here

Piriton Syrup is handy to keep for things like this,also handy for Chicken Pox etc.

Thanks Sawyer64, that is what it looks like 'Hives', more likely the 'Physical Hives'as she was rubbing up and down the sofa just before.
They have totally gone now, but it was quite alarming last night.
Don't know what i'd do without MN