top six canine skin ailments-from Family Dog
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The Top Six Canine Skin Ailments
By Jeff Grognet, DVM
Canine skin disease is the most common health problem presented to veterinarians. It can be frustrating to diagnose, because many diseases look the same yet require different treatments. But because just a few diseases account for the majority of dermatologic cases, the odds are good that the veterinarian will make the correct diagnosis and create an appropriate treatment plan.
The most common skin ailment — and the one that generates the most itch for dogs and pity from their owners — is allergies. Three types of allergies plague dogs, and each is treated in a different way.
The first is flea allergies — a reaction to flea saliva left behind when the flea takes a blood meal. Once fleas have ingested enough blood, they lay eggs — a tremendous number of eggs. These minute white spheres are so smooth they are sometimes called ‘Teflon balls.’ They fall off the dog and into cracks in the couch, deep into the carpet, underneath the skirting boards, or wherever your dog spends time, including outdoors. Flea eggs hatch when it’s warm and humid. Vibrations and exhaled carbon dioxide generated by a suitable host are the triggers for fleas to explode from their shells. Once they find their next victim, they consume blood, lay eggs, and start the cycle all over again. Obviously, flea allergies occur only if the insects are around to cause them. Look for evidence of fleas, such as flea dirt in the dog’s hair, especially on the back above the tail. Controlling the fleas will control the allergy.
The second common allergy is a reaction to specific proteins in food. Though food allergies get a lot of attention, they are actually quite rare, only comprising about five percent of allergies. Feeding a hypoallergenic food is the solution.
The third allergic reaction, atopy, accounts for more than 80 percent of allergies in dogs. This is a reaction to allergens in the air, such as house dust, molds, fungi, and pollens, that are either inhaled into the lungs or absorbed through the skin. Dogs shouldn’t produce antibodies against these allergens, but for some unknown reason their immune systems go out of control. The combination of antibody and allergen cause the release of histamine, generating intense irritation. It’s been likened to being bitten by hundreds of mosquitoes.
Most atopic dogs itch only in one particular season. It could be spring or summer, when certain pollens appear. It may be winter, if the reaction is to house dust or molds. But some dogs have yearlong allergies, reacting to pollen in the summer and house dust in the winter.
Prednisone has been used for decades to treat atopy. It’s usually effective, but is fraught with side effects—excessive drinking, weight gain, skin infections, and lack of energy. The drug Atopica, introduced recently, is a canine-specific form of cyclosporine that controls the itch associated with atopy yet has no side effects.
Number Two: Fleas Again
Skin parasites — fleas and ticks — are the second most common skin ailment. Even when a dog does not have an allergic reaction to them, fleas are extremely irritating. They scoot around on the skin surface and take their blood meals by biting the poor dog, causing physical trauma to the skin. If your dog is suffering from fleas, use a product that kills them before they bite. Many topical products are available for this purpose, and some control ticks as well. Ask your veterinarian for advice.
Number Three: Bacterial and Yeast Infections
The third most prevalent canine skin problem is recurrent bacterial and yeast infections. Healthy skin normally resists infection, so we see these problems only when other diseases, such as chronic allergies, thyroid imbalance, or Cushing’s disease, impair the dog’s immunity. In fact, if you see a skin infection in an older dog that does not usually have skin problems, look for an underlying disease.
There is also a serious problem looming on the horizon: methicillin-resistant Staphylococcus aureus (MRSA). MRSA is the number-one infectious cause of human emergency-room admissions. This “super-bacterium” possesses a gene that makes it resistant to methicillin and other common antibiotics: It is very hard to kill. Veterinary dermatologists believe the same pattern of resistance in Staph bacteria will erupt in dogs. The key is to control allergies and other diseases so that immunity is not compromised.
Number Four: ’Ear! ’Ear!
The ear is just a specialized type of skin, and otitis—ear problems—rank fourth on the list of common skin problems. Ear ailments can be in the outer ear (otitis externa) or the middle ear (otitis media). Usually categorized as inflammatory or infectious, they are often both. Many are secondary to allergies.
The problem with otitis is that it’s self-perpetuating. The glands that line the ear canal respond to inflammation by stepping up wax production. The wax keeps the ear moist, promoting bacterial and yeast growth. As these organisms grow and produce more inflammation, they perpetuate the cycle.
There is no point putting ointment in a dirty ear, because the medication will never reach the skin surface. Therefore, the first step in treating otitis is to clean the ear. Then, a steroid medication is used to quiet down the glands, reduce wax production, and break the cycle.
Ear problems require early detection and treatment. This means checking the ears on a regular basis —perhaps weekly — and if wax is present, cleaning it out. A mixture of 50:50 water and vinegar can help clean the ear and kill infectious organisms.
Number Five: Mighty Mites
The number-five skin ailment is mites, both on the skin and in the ears. Ear mites—tiny bugs that feed on ear debris—defecate in the ear canal. This induces inflammation, which leads to itching and secondary infections. There are many effective treatments for mites, but all dogs that come in contact with an affected canine must be treated to eliminate carriers.
Skin mites (Demodex and Sarcoptes) cause mange. Sarcoptes (scabies) creates a persistent itch that can trigger skin damage, especially on the ear flaps and elbows. It is easy to treat with one dose of Revolution or ivermectin. (Some breeds are sensitive to Ivermectin; your vet can prescribe the appropriate treatment for your dog.) In contrast, Demodex mites live deep in the hair follicles. They tend to concentrate on the face and legs and create infections that only later become itchy. Demodectic mange is very hard to treat and sometimes requires lifetime therapy.
Sixth and Last
The last of the common skin issues is keratinization disorders. These tend to occur in particular breeds, such as Cocker and Springer Spaniels, Doberman Pinschers, West Highland White Terriers, and Irish Setters. Commonly called seborrhea, it is due to a fault in the proliferation and maturation of surface skin cells. The result is dry or greasy accumulations of scale on the skin surface. Dogs with this type of dermatologic problem have a rancid odor, can be very itchy, and lose their hair. A related syndrome is sebaceous adenitis, a hereditary disease in standard Poodles, Akitas, and Samoyeds.
The only treatment available for sebaceous adenitis and the keratinization disorders is supplementation with certain forms of vitamin A, controlling infections with antibiotics, and copious bathing and moisturizing. Treatment is lifelong.
Though each of these skin diseases requires a different treatment, there are some things you can do at home to help your dog. If he has fleas, get them under control. If there is excessive scale on the skin surface, use a shampoo to clean it off. (This often helps reduce the itch.) If his ears are filled with wax, clean them out. But if the problem continues, it’s time for help. Your best resource is your veterinarian: You can rely on his or her expertise to determine the exact problem and how to control it.
This article originally appeared in the March/April 2008 issue of the AKC Family Dog and is reprinted with permission. Jeff Grognet, DVM, is a regular contributor to AKC publications.