What Causes Rashes In The Joints And Itchiness All Over The Body?

hello.im 26 yrs old female.i have been getting some rashes mostly over the joints and itching all over the body for last 2-3 days and also my hands and foot were swollen for a day ,is it an allergy to something ar a disease symptom.also i havenat got my menstruational period this month and im trying to concieve .so please if you could help me.