Red bumps on arms, legs for ~3 yrs. Had biopsy, can't id, mybe allrgy, dr not sure. Scratch = open sore over time. Got in afghanistan. Bumps last for months. Very itchy! Allrgy meds & creams don't help.

See a dermatologist. When you go , bring, all current and previous agents which you have used. Claratin will not help this. No antihistamine will help.
Itchy bumps. You may have a parasite or itch mite infection. Have you seen a dermatologist? Keep searching for the cause.