Rash red smallish bumps, itchy spread over months from nape of neck down back to thighs/. doesn't look like ringworm but could be other fungal?

Rash on Back: Without seeing the rash it is difficult to make a diagnosis. However this could be tinea versicolor. Tinea versicolor is fairly common. It is caused by a type of yeast fungus called pityrosporum ovale. This fungus is normally found on human skin. It only causes a problem in certain settings.

Best to have it : Looked at.Hard to say without additional information.May just be heat bumps and dry skin.In the meantime, you can take some antihistamines like benadryl, (diphenhydramine) Claritin , Allegra , zyrtec or any generic equivalent to stop you from itching and avoid skin infection.