Hello there,
You say you have skin allergies but without a picture it is hard to even
begin to suggest what you make have. A picture would probably get
you more responses too. Eve
May be you have contacted a poison plant or there source....something like poison ivy in the USA finds most of us "allergenic" a rare few are unaffected by contact with that plant.
The first line of defense is to identify the source and avoid it, then if contact is made washing with lots of soap and water would be good followed by any anti-itch preparation you can obtain, scratching always spreads the itch/infection.
Psoriasis can appear that way, but early rashes can look very similar to one another. It is very hard to help you without lots of history, the location, a picture, your age, other symptoms. But common causes of itchy rashes are eczema, ring worm, other fungal infections, psoriasis. You can get a rash called a Christmas tree rash that is on your torso. I'm not sure if those itch or not, but that one is a virus that goes away on its own. There is contact dermatitis, which could be from metal (nickel) or from a soap or perfume or detergent you are allergic to. Then there are food allergies and problems caused from vitamin deficiencies (which could come from an absorption problem like Celiac disease). Rashes are complicated, yet if you go to the dermatologist they will say, Well, it's this or it's that, and then give you an Rx for hydrocortisone cream product and send you on your way. Alas, it usually doesn't work, but may cause scarring after thinning your skin.
It's a common problem. If an antifungal cream like Lotrimin has no effect, you might want to see your primary care doctor.