[anonymously]

What medication are you talking about? Frequent bathing at least once a week with a shampoo like Malaseb, unless your vet advises differently, might help.
My dog with environmental allergies and a sensitive stomach does well on Nutrisca Salmon and Chickpea (dry and canned) as a base. Check Chewy.com for prices and delivery.

Check the search engine here for “allergies” you may find some helpful tips.