I am sorry to hear tuffy is scratching. There are many causes for itching but the main categories are parasites (notably fleas), allergies and infection.
In order to check for fleas take a fine tooth comb through his coat and if there are any little black specks of dirt of the combed hair try putting them on wet white paper., If they are flea dirt they will turn the paper a rusty red color. I am afraid flea baths in my opinion are a waste of time, they just don't last long enough, aren't nice chemicals to use and don't kill enough fleas. When I am using flea control I want something that has at least a 99% kill rate, 60% isn't good enough. You will be much better using something like advantage or frontline which are spot on products that last a month and a very safe and easy to use. If you do find a flea problem make sure you treat for at least 3 months as the eggs can live in the house for approx 3 months and hatch out at a later date.
In terms of other itching issues, if you are not finding any fleas then it would be worth taking him to your vet who can give him something to help. How does his skin look under his coat? and redness or spots? any odor? any discharge or crusting? If there is skin infection too he may need antibiotics and possibly antiinflammatories to help him feel better.
I hope he feels better soon, Dr Spar