What Causes Itchy Rashes On Hands?

Dear Sir Im gina 47 yrs old. My skin allery started last march 19 until present. It apears all over my body but it only last for 10mins and will disappear. It looks like a cat scratch- elongated in form and a little bit warm. I also noticed that when i put pressure on my skin it becomes itchy and rashes appear i can even write words. It also provoked by heat. I tried anti allergy medicine like alerta ( loratidine ) but gives temporary relief.