Red, raised, itchy rash

I did have that once, about 20 or so years ago. I don't know what it was, never found out. I have a feeling it may have been some sort of inflammatory response as I later discovered I had an undiagnosed auto-immune condition I'd probably had all my life. I had quite a bit of stress at the time.

Sounds like hives (or urticaria, medical term).
I have been dealing with this menace for 5 years, it began a day after the Pfeiser covid booster. Not saying that's what caused yours but just for context I know what it feels like.
Aloe Vera gel (kept in the fridge) helps a bit. And Cetrazine seems to be the best anti histamine, recommended by G.P.

There are multiple things it could be, as well as multiple things that can have set it off.
I think you will need to contact a GP.

Try asking your pharmacist.

Could it be caused by something you have handled in the garden? I get a similar rash when cutting down ivy if it touches a part of skin not covered by clothing.

I had a rash like that when I was in my 30's ,it started on my back then spread to my chest , elbows to wrist and thighs to knees, it looked as if I had been stung by nettles, it was extremely itchy, GP sent me to see a skin specialist,but as usual by the time a got to see the specialist it was almost gone...3 months it lasted.
He told me it was PITYRIASIS ROSEA and once I'd had it , it wouldn't come back...and it hasn't .

I had a similar rash a few years ago on my face and upper body. Very itchy and tingly.
The culprit was a new shampoo I was trying. It had tea tree oil as part of the ingredients. I stopped using it and the rash went.
Have you changed to a different shampoo recently?

No, I haven’t changed any toiletries. I only use soap in the shower (not on the rash) and a mild shampoo once a week. I don’t wear perfume and very rarely use make up. Thank you for your comment though because it may help someone else.

It maybe quicker to see your local Pharmacist.

GrandmaT2010 do you take Cetirizine hydrochloride for your antihistamine? If you take it regularly and have a break, you can get a rash as described. Starting cetirizine again relieves the rash and itch.

This could be caused by such a multitude of things you are allergic to, that if it worries you, you need to see a doctor.

Not even the physicians amongst gransnetters can possible answer your query without seeing the rash.

pably15

I had a rash like that when I was in my 30's ,it started on my back then spread to my chest , elbows to wrist and thighs to knees, it looked as if I had been stung by nettles, it was extremely itchy, GP sent me to see a skin specialist,but as usual by the time a got to see the specialist it was almost gone...3 months it lasted.
He told me it was PITYRIASIS ROSEA and once I'd had it , it wouldn't come back...and it hasn't .

I had that earlier in the year - started immediately after I tripped and fell on the patio. It was diagnosed as pityriasis rosea.(The nurse said it was usually something that younger people got - at least that was some consolation that my body thinks it’s younger 😂). She said it will just go eventually as quickly as it came. And it did. It’s very odd. Just took anti histamines but nothing much improved it.

My daughter has a very itchy skin including small blister like spots. She is being tested for coeliac disease.

Try AI to get the answer. It should ask you lots of questions and then list the salient points to ask a pharmacist or Dr. I've found it very helpful.

Dermatitis Herpetiformis is a type of rash caused by gluten (coeliac disease). I had this on hands and feet in my 60's and no diagnosis for few years.

Had this really recently- my skin on arms and shoulders went itchy and felt ‘scaly’ with lots of tiny bumps. I briefly took antihistamines and used antihistamine cream. I had ducked under a bush in the garden to retrieve some litter - so I blamed something that came off the leaves - but what?

A photo would help, as quite a few rashes are red, raised & itchy but look different.

Try a pharmacist.

I get this side effect from Proton pump inhibitors such as omeprazole…

Try to see your GP.