Suggest Remedy For Itchy Blisters On My Arms And Legs?

I have several small very itchy pimples on my arms and legs. 1 inparticular on my right forarm and 2 on the inside of my left knee. I have suffered a silly cough for the last 3 years which seems to be baffling the doctors at the hospital.

One doctor, a chest physician, mentioned that she thought my skin spots were sarcoid and ignored them. They are very itchy. What should I do?