What Causes Itching Red Bumps And Rashes Allover The Body?

Hello. My family dosent have health insurance so me and my siblings cant go to the doctors. Well my little sister (14 years old, 220 lbs, 5'9") has had a persisting rash (about two months) that has gotten worse. Her symptoms are: Red bumps everywhere, (neck, hands, legs, bottom, stomach, arms, legs, back), no fever or nausea, the bumps itch, they are sprinled everywhere and red, theres no white around them or amy rings, she has scratched them open and some have broken open and looked like a rough patch of pink skin. Her hands are becoming rough and are swollen, calloused over on the top, and covered with the bumps. She is always itching. Help please.