Archie’s Itchy

I need some help. I recently brought Archie home from the Capital Area Humane Society.  Unfortunately my cats, no doubt out of revenge, then shared their fleas with Archie, who happens to be allergic to fleas and apparently has some inhaled allergies as well.  The poor little guy scratches constantly.  We have done the whole flea irradication program, all the animals have been treated and Arch got another allergy shot yesterday, but he's still itching.  Does anyone have a home remedy or a suggestion for how I can make him more comfortable?  He's such a good dog I hate to see him so itchy.  Please feel free to contact me via email or facebook and let me know if you have any suggestions.  Thanks.