Rash - Little red bumps all over my body

Does anyone have any advice for the following:

3 days ago i notices a rash developing on my lower legs, lots of little red bumps. At first i thought that perhaps my skin did not like a new razor I had used to shave my legs (it had a moiusture strip in it), but then noticed the next day it had spead to my forearms... since then is has spread to all of my arms and legs, a few spots on my shoulders and chest, a fe dots on my hand and only a couple on my face. They are extremely itchy. I have been taking an intihistomine tablet and calomine lotion.

i saw a Dr on tuesday but he had no idea what it was and said it might be a virus or it might be an alergic reaction but basically said there was nothing he could do.. as it has been getting worse.. not better i was consiering going back to see my normal GP... any suggestions b4 I go?