allergy symptoms ?

Hi all. I don't know if this is the right place for this, but I've had a weird thing going on for since about January now. When I take a shower, I break out in spotty places on my arms and shoulder and it seems to be in the same places on both arms. I also get itching on my upper back and the upper part of my buttocks. It seems to appear about 3 to 4 minutes while in the shower and lingers for about 30 to 45 minutes before it goes away. I've tried to reduce the temperature, switch from body was to regular bar soap like Ivory or Dove. It seemed to help for awhile but it's coming back now. I also bought some Lubriderm for sensitive itchy skin to help with my dry skin.

I do have Rheumatoid arthritis and take medication for that, as well as high blood pressure. Current meds I'm taking are Plaquenil 200 mg twice a day (this I stopped in Jan along with the sulfa but started back on it 3 weeks ago for RA) and Carvedilol 6.25 mg twice a day. I've been taking a Benadryl every day for a few days now for allergies, and generic Prilosec about every other day for about a week and a half.

Medicines I used to be on were Sulfasalazine (stopped in January) and HCTZ (stopped about 3 weeks ago).

I just wonder if maybe I've had an allergic reaction to these and they're still in my system. I think we have hard water where I live as well. Any ideas? Thanks in advance..