I Have Random Areas On My Body; My Neck, My

I have random areas on my body; my neck, my fingers at the joint, and also on my elbow and wrist, that began as small reddened areas that itched. They began to get larger and swollen, hot to touch when I scratch them...typically they will resolve in a few days, but this time they haven't...I use hydrocortisone and Benadryl for comfort but I'd like to know why they occur....I haven't had any new colognes, perfumes, soaps, or anything else.. The area looks like lyme disease but it doesn't hurt and the area is more red than the bulls eye