urticaria
"In my 40s I started getting contact hives when lifting heavy object on my arms. As I got older it started getting worse and I often would also get rashes. After multiple visits to various doctors one finally took a biopsy or one of the rashes. It turns out I was allergic to the sun, a form of Lupus. I basically lived out doors in shorts and a t-shirts and the hives and rashes did not correspond to where the sun hit my body.  I take one to two cetirizine pills per day (day/night) and also one Ranitidine 150 mg (another histamine inhibitor) and stay out of the sun. I cover up at all times and the hives are mostly gone. Before this I would get thick large hives from any pressure, even sitting. "