Started approx. 3 yrs. ago with quarter sized itchy rash with blisters at bottom of spine. It reocurrs approx. once a month--with pain going to hip and down the leg, with numbness and tingling in foot. One dr. took blood test & advised it was zoster; a dermatologist took a skin sample (after rash had dried up) and said it was simplex. I'm now having a endoscopy to test for celiac disease. The celiac panelI had for that showed elevation, but not conclusive. The recurring rash, with accompanying severe pain to hip/leg and exhaustion for days before, is wearing me down. Advised to take two 250 mg. Famvir every day now--it makes me nauseas. The last rash moved from the lower spine area (the quarter sized) to a larger rash in the periformus area--moving closer to the hip. Rash starts as a lump, then breaks out into the blisters. How can I find out for sure if it's zoster, simplex, herpetiformis--do I go to a dermatologist to do a test with the tissue sample, or is there a definitive blood test? I am 58, also diagnosed with chronic fatigue/fibromyalgia/extreme hypothyroidism. This "rash" and the pain keep me from exercising, the exhaustion and pain is so great, thus weight gain and little exercise to help with the fibro. Help please.. Thank you.