An allergy is a reaction of the immune system. It's caused by exposure to an allergen, which is any substance — medications, insect bites or stings, grasses, pollens, molds, and foods — capable of causing an allergic reaction. Dogs can inherit allergic tendencies or acquire allergies, and it's estimated that one in seven dogs suffers from some type of allergy.
Allergic Skin Disease
Labs are among the breeds that are prone to allergic skin disease. It usually appears when a dog is young — one to three years old. Atopy, which is usually an inherited tendency, is characterized by an itch-scratch cycle that's usually triggered by pollens. Eventually, the dog may begin reacting to all kinds of allergens, from dust and feathers to molds and wool.
Dogs with atopy itch and scratch constantly, resulting in hair loss and scabbing. The skin becomes thick and flaky. It's also not unusual for dogs with atopy to develop other infections that develop as a result of the wounds caused by scratching.
It takes lots of testing to determine whether a dog is suffering from allergic skin disease or some other type of allergy. The veterinarian may order skin scrapings, bacterial and fungal cultures, intradermal skin testing (which involves injecting tiny amounts of known allergens and observing the skin reaction), and even a trial period on a special diet. A good flea-control plan is also important, because FAD can resemble atopy.
Once atopy is diagnosed, there are several ways to manage it. The first is to change the dog's environment — as much as possible — by limiting exposure to known allergens. Antihistamines, essential fatty acid (EFA) supplements, and medicated shampoos can help control itching and scratching. A Lab that suffers severe itching may need intermittent low doses of corticosteroids to relieve itching. When all else fails, allergy shots (hyposensitization) can be given. This involves skin testing (to identify specific allergens) and then desensitizing the dog to these irritants through a series of injections.
Atopy usually starts out as a seasonal condition but can become a year-round problem if the dog develops multiple allergies to common household or environmental substances, such as wool or house dust.
Flea Allergy Dermatitis (FAD)
A single bite from a single flea can trigger flea-allergy dermatitis, which is the most common allergy seen in dogs. The allergy occurs because many dogs are sensitive to a particular substance in flea saliva. Dogs with FAD itch like crazy, and their skin is inflamed, red, and bumpy. Depending on where you live, FAD can be seasonal or year-round.
The best treatment for FAD is a good flea-control program, so talk to your veterinarian about appropriate products to use. Until fleas are under control, itching can be controlled with antihistamines and — if necessary — short term doses of corticosteroids. Some dogs develop skin infections from chewing at the itchy spots. These can be cleared up with topical (on the skin) and oral (taken by mouth) antibiotics.
Signs of food allergies are severe itching and red, bumpy, or raised patches of skin. This rash is usually seen on the ears, feet, stomach, and back of the legs. Wheat and corn are common food allergens.
Feeding your Lab a hypoallergenic food won't prevent allergies from developing. These foods contain unusual proteins that most dogs haven't been exposed to, which makes it easier to figure out which ingredients are causing the problem.
When a food allergy is suspected, the veterinarian will recommend putting the dog on a hypoallergenic diet for a certain period of time — usually six to ten weeks. A hypoallergenic diet contains unusual ingredients — catfish and potatoes, for instance — that the dog has likely not encountered before. It's also free of artificial colors, flavors, and preservatives. If the food allergy goes away while the dog is on a hypoallergenic diet, it's necessary to add ingredients back to the diet until the allergenic culprit is identified. Then a homemade or commercial diet can be chosen that doesn't contain the allergy-causing ingredient(s).
This type of allergy occurs when a dog comes in contact with a substance that irritates the skin. Common items that contain such irritating substances are soaps and shampoos, plastic or rubber dishes, flea collars, wool or synthetic fibers, and topical medications containing neomycin. If your Lab develops skin irritation on the nose or lips (plastic or rubber dish allergy), irritation or hair loss around the neck (flea collar), or irritation on the feet, legs, and stomach, suspect a contact allergy. Try to identify and remove the offending substance. In the meantime, your veterinarian can prescribe medication to help relieve the itching.
What Are Hot Spots?
These warm, painful, swollen patches of skin usually develop in response to flea bites, allergies, other skin diseases, or lack of grooming (when dead hair gets trapped against the skin). If your Lab gets a hot spot, clip away the hair and clean the skin with chlorhexidine. Severe or numerous hot spots may require a trip to the veterinarian so the dog can be sedated or anesthetized during this procedure. Your veterinarian can also prescribe medication to relieve the itching until the hot spot clears up. Your Lab may need to wear a cone-shaped Elizabethan collar to prevent him from biting or scratching at the area.