I have itchy rashes on both my hands and arms due to caffeine allergy. Please help.

Hello doctor,

I have been experiencing very itchy rashes on both my hands and a little bit on my arms for one week. I suspect that the cause of it was an allergic reaction from cold brew coffee. Before the rashes occurred, I was already experiencing some sort of dyshidrotic eczema on both hands. It was already healing. But, on July 29th, I drank a cold brew. It was my first time to drink cold brew that I made with ground coffee (dark medium roast) steeped for about 10 hours. I was aware that cold brew has higher caffeine content. So, I suspected it might be that my body cannot handle that amount since I never had problems drinking instant coffee. I use Bepanthen itch relief cream for itchiness.