I have several very itchy, red, bumps spread randomly on my arms, legs, and stomach?

Hi, i was wondering if someone could help me with a skin rash/bump/bite. I have several very itchy, red, bumps spread randomly on my arms, legs, and stomach. I have yet to find anything that works for it. None of the diagnosis from the doctors have worked. I thought it could be from my father having targeted chemotherapy at home. But, that was quickly shot down by his doctor. I am not positive it is contagious. It seems to have varied, but still traveled, to all the household members. Each one different and not responsive to any treatments. Any help would be great!