Red streaky marks on skin

[AJ2009]

My DC came down last night saying there was a warm feeling down the middle of his back. I had a look and this is what was there.

It was very warm to touch and cool on the other side which wasn't affected.
I thought maybe an allergic reaction but no other symptoms. Maybe a heat rash? No sunburn or burnt with anything.

But I just don't know for certain what it was.
It wasn't raised skin, the redness followed over his shoulder and armpit. After an hour it had faded quite a lot.

He had just had a shower but used all the same stuff he uses every shower and water it never hot.

He felt completely fine in himself too.

Anyone else had similar streaky reactions?

Bump

Hmm. looks like a direct reaction with something that touched the skin like the shampoo or soap/shower gel getting washed off. It is possible to develop allergies or types of dermatitis out of nowhere

meant to add - this happened to me with herbal essenses brand out of nowhere

Could be a possible form of urticaria.

Otherwise, looks like water too hot, or cleaned against a radiator.

*leaned against

I thought maybe a reaction to the stuff he uses but been using it for so long. I guess who can react at any time can't you.

PP my son won't step foot into shower unless it's luke warm/ warm water, hates any kind of heat he can't handle and no heating on last night for him to lean against.

Thanks all

That looks like a contact reaction. Possibly something didn’t get rinsed off well so hot more exposure than normal?

You can react to something you have been using for years. It’s not always a new product.

It's possible a formulation has changed. Supply issues have forced manufacturers to substitute ingredients in some products.