During the summer heat and humidity... is it common for eyes to mat up more often?
Dog allergies are not like human allergies for the most part. When a dog is allergic it usually manifests itself in skin, ear or eye issues. Benedryl is good for bee stings and the such but I wouldn't use it unless there is abnormal swelling.Probably a seasonal allergy. Talk to your vet but you can give benedryl and zyrtec for allergies.