Irritated belly :( allergy help?

Hello! This is Hank, he’s about 1 1/2 years old. We live in Arizona, allergy season is definitely here as well as the heat. Hank started itching a lot about a couple weeks ago, especially under his armpits. I treated the current irritation with medicated wipes and started him on a daily 24-hour allergy medication (Costco brand AllerClear). The wipes seemed to soothe him, and cleared up his armpits and the allergy med seemed to help! But even with all that, he is now back to persistant itchiness and an irriated belly 🙁 any tips? I have Googled a lot of things that lead back to allergy shots, would like to only use that as an absolute last resort. He’s our first and only basset, always learning new things with how to help him live his best life!