Hives are red, raised welts on your dog's skin that appear due to his body's natural response to allergens. Allergens such as insect bites, pollen, insecticides and shampoo can cause an allergy flare-up, which usually disappears within 24 hours after the first signs of allergies, according to "The Doctors Book of Home Remedies for Dogs and Cats." Similar to humans, pets can take over-the-counter medication such as antihistamines to reduce hives and other uncomfortable symptoms. A reaction can also occur if your dog is allergic to an ingredient in his food.
Often, the soap used to clean your dog can cause an allergic reaction. Many pet shampoos contain sodium laureth sulfate, propylene glycol, mineral oil and ethyl alcohol, which cleanse the skin but can also cause skin irritation due to stripping the skin of essential oils, according to "The Doctors Book of Home Remedies for Dogs and Cats." The result is itchy, red skin with small bumps. Reduce allergy flare-ups by switching to an organic shampoo or a mild shampoo and limit shampooing to once a month or when he starts to smell.
Hives can also develop as a result of protein in your animal's diet. According to "The Doctors Book of Home Remedies for Dogs and Cats," your veterinarian may switch your dog's diet to commercially prepared foods that have protein your dog has not consumed. She may also be put on a special diet that consists of food made from fish and potatoes. Your veterinarian may have you slowly reintroduce certain foods back into the diet to determine which one causes hives. Hives and other allergy symptoms should subside within a few days or weeks after switching her diet. If your dog continues to experience allergy symptoms after switching commercial foods, your veterinarian may tell you to prepare food.
Your dog can develop allergies due to outdoor allergens such as pollen, ragweed and mold spores. According to "The Doctors Book of Home Remedies for Dogs and Cats," ragweed is one of the common pet allergies that occur during the fall. Mold spore levels increase during the fall as well, due to dead leaves accumulating on the ground. Mold spores can attach to your dog's coat, which causes hives. Brush off your dog with a hard brush to remove mold, and bathe him once a week to remove imbedded allergens, according to "The Doctors Book of Home Remedies for Dogs and Cats." Antihistamines can also help alleviate hives and other allergy symptoms when given daily.