re: Dog overnight health issue...suggestions welcomed. Updated

Benadryl is safe for your dog. Google dosage for his weight. Easy to find dosage recommendations online. If it seems to help, then as others stated it’s likely food. Change his protein and perhaps feed a limited ingredient diet (plenty of dog food available). Just make sure it’s not grain free or filled with legume fillers as that can cause heart issues.

If Benadryl doesn’t help then unlikely it’s allergies. Check in between his toes or under his paws. Is it red and inflamed? If so, could be yeast.

If so try probiotics (eating plain unsweetened yogurt can help). Make sure it’s unflavored and unsweetened as certain sweeteners can be toxic (xylitol is highly toxic). Antifungal shampoo and diluted vinegar spray can help. Vet can also write an RX