What the dog really needs is a medication that doesn’t have any side effects, is easily available without prescription, and is able to control the allergic reactions effectively. One product that has all these features is Zyrtec for dogs.
Allergies in Dogs: Symptoms and Triggers - Pets WebMD
Most dogs recover from an allergic reactions to antibiotics. Life-threatening symptoms are rare, and even anaphylactic shock can be treated as long as your dog gets emergency care in time. Your dog will likely have the allergy for life, however, so this will need to be managed. Any new veterinarian should be informed of all your dog’s known allergies. Discuss side-effects and the possibility of an allergic reaction anytime a new medication is prescribed, so you know what symptoms to watch for in your dog. If your dog has had an anaphylactic reaction to medications or other triggers, ask the veterinarian about getting a dog Epipen so that you have something on hand to use in case of another crisis.
A New Treatment for Skin Allergies in Dogs - petMD
Antibiotic allergies are typically diagnosed because owners notice an unusual response when their dog begins a new medication. Rarely, dogs could also develop a new allergy to an antibiotic which previously didn’t cause a problem. There isn’t any way to test for an antibiotics allergy without actually giving the drug to your dog.
Dog Allergies: Symptoms, Causes, Testing, Treatments and 8 Tips