Most OTC antihistamines can be used in dogs, however you should **never** give any medications to your dog without the advice of your veterinarian. Legally though, we cannot direct you to medicate your pet in the absence of a physical exam and a VCPR (veterinarian-client-patient-relationship).
Allergies can be frustrating to diagnose since they can have multiple causes (
environmental,
food,
flea bites, etc.). Schedule an appointment with your veterinarian. Discuss
food elimination trials and
allergy testing and if antihistamine use is indicated, he or she can give you a proper dose, The medication may provide some relief but your task is to try to determine what your dog is allergic to and decrease or eliminate it.