itching in fore arm

from so many days i hv severe itching in my forearm, reason is not known to me. I have tried so many lotions but of no use. There is no visiable mark on the skin. It appears to be normal on a normal look. Please advice

[Caryopteris]

You might want to get tested for food allergies if it doesn't clear up.  Try not to scratch.  Sometimes putting rubbing alcohol on the skin and allowing it to evaporate is an effective alternative to scratching.  The itch sensors are underneath the skin, so scratching is a distraction from the itch by overriding the feeling with pain.