Several dog breeds, such as Golden Retrievers, are highly predisposed to allergies. Some allergies are seasonal, some appear at various life stages, and some skin diseases become lifelong problems requiring frequent or continuous treatment by a veterinarian.
Allergies are caused by the dog's reaction to various allergens. The most common types of allergens are flea saliva, inhaled substances (pollen, mold, dust), and food ingredients.
Flea allergies
The most common and most debilitating is flea allergy dermatitis, which is a hypersensitivity to the protein in flea saliva. It's most commonly diagnosed after age 2, is most severe from midsummer through fall, and always requires veterinary care. In warmer climates, it can be a year-round plague.
In flea-allergic dogs, it only takes one tiny flea bite to set a major allergy machine in motion. Flea allergic dogs will scratch and bite themselves raw, with most of the intense itching and biting occurring near the base of the tail.
Your veterinarian will prescribe anti-inflammatory medication, an oral or spot-on flea preventive medication, and also recommend stringent flea control, which includes the environment (house and yard) as well as the dog. Routine grooming, brushing, and thorough body inspections are also vital for flea allergy preventive maintenance.
Inhalant (atopic) allergies
Inhalant (or atopic) allergies are the second-most-common culprit, with grasses, pollen, molds, danders, and even dust making your dog completely miserable. Atopic dogs rub their faces, muzzles, and eyes, scratch their armpits and ears, bite their feet and legs, and may develop red and swollen patches. Indoor air cleaners, air conditioning, and good environmental sanitation are helpful in keeping indoor inhalants to a minimum.
Veterinarians commonly treat inhalant allergies with antihistamines, steroids, and fatty acids, and recommend topical therapy with shampoos and rinses to make the dog more comfortable. Your vet also can refer you to a veterinary dermatologist for allergy skin testing to determine the offending allergen. If your dog is treated with a steroid, you need to know all about side effects and long-term effects to make the best decisions for your dog.
Occasionally, a dog will react to some everyday element in his environment, like carpet fibers, bedding, cleaning agents, plastics, or fertilizers. He may scratch himself hairless, especially in his armpits, lower abdomen, groin and bottom of his feet. Finding the culprit can be difficult, but then at least you can make him comfortable by eliminating it from his life. Keep him off fresh applications of fertilizer (always avoid weed killers and pesticides!), wash his feet after running on freshly mowed grass, and use shampoos that contain healing agents and are free of perfumes and dyes.
Food allergies
Although food allergies are uncommon, they also are not seasonal and do not respond to corticosteroids. As with inhalant allergies, food allergies can cause itching, which makes the dog scratch, rub, chew, bite, and lick at his skin. The most common offenders are beef, pork, chicken, milk, eggs, fish, corn, soy, and preservatives. Diagnosis takes time, because your vet must remove the dog from all commercially prepared foods and replace it with a two-ingredient diet with adequate supplementation of vitamins and minerals for a period of three to five weeks, then gradually introduce a food to the dog.
Food allergy is sometimes confused with food intolerance. Food intolerance is an abnormal physiologic response (like intestinal upset) to food, while food allergy is an immunological response to an ingested substance.