Two surprising causes of skin problems in dogs

If they result from diet, low-cost generic food or home-prepared meals could be to blame


[From Tufts October 2010 Issue]

When your dog has a lackluster coat, flaky skin and hair loss, the cause could be an underlying medical problem. If, however, the condition resulted from his diet, the reason may come as a surprise.

“Most problems are associated with feeding low-cost generic diets or home-prepared foods in which balance may be an issue, says dermatologist Lowell Ackerman, DVM, a Your Dog advisory board member. “If a well balanced diet is fed, it is rare to see diet-related hair coat problems.”

There are genetic situations in which dogs have higher requirements for some nutrients, Dr. Ackerman says. “Then supplementation is needed only to achieve specific goals. For instance, many atopic (allergic) dogs benefit from supplementation with fish oils rich in specific fatty acids, such as eicosapentaenoic acid (EPA).”

Common ingredients
Allergies can also play a role in skin and coat problems. “They usually affect a dog’s skin and ears, causing itching, scratching and infection,” says nutritionist Sally Perea, DVM, MS, also a Your Dog board member. “Common ingredients like beef, chicken and dairy are often reported as causes of allergies.”

Fortunately, adverse food reactions are estimated to account for only 10 percent of allergic patients, and allergic patients represent 10 and 15 percent of the purebred dog population, so adverse food reactions are seen in only a relatively small percentage of dogs, Dr. Ackerman says.

Some commercial pet foods contain ingredients like corn, wheat or soy. In addition to common meat ingredients, these ingredients can also be a cause of food allergies. Determining the problem ingredient requires diligence, says Dr. Perea, senior nutritionist at Natura Pet Food.

When veterinarians suspect a dog has a food allergy, they often will conduct an elimination diet trial, which is the gold standard for testing, Dr. Perea says. “It involves removing specific foods from a dog’s diet that are thought to be causing allergy symptoms.”

In some cases, a dog will experience relief from itchy, dry skin within a few days, although it can take up to three months before a noticeable improvement is seen.

Important fatty acids
In addition to a proper diet, omega-3 and omega-6 fatty acids are important in maintaining skin and coat health. These fatty acids support the cardiovascular, reproductive, immune and nervous systems. They manufacture and repair cell membranes, enabling the cells to obtain optimum nutrition and expel waste products.

The body doesn’t manufacture essential fatty acids, so they must be obtained from food. Most high-quality commercial pet foods contain sufficient amounts of EFAs. In some cases, however, supplementing a dog’s diet with specific fatty acids will help soothe and calm itchy skin. Other fatty acids can actually worsen the situation. Be sure to check with your veterinarian before supplementing a diet.

A caution about fatty acids, especially omega-6: they have a high fat content, which can lead to weight gain if not closely monitored. “Foods that contain higher quantities of essential fatty acids tend to have 400 to 500 calories per cup versus 300 calories per cup for a lower-fat food,” says Dr. Perea. “If your dog is gaining weight on the new diet, you may need to cut down the amount of food you’re feeding him.”

Along with nutrition, a variety of underlying conditions can cause skin and coat-related problems, including hormonal disorders and environmental and flea allergies, Dr. Ackerman says. “Each requires medical detective work to properly diagnose the problem and then to direct treatment at the specific underlying cause.”

Hypothyroidism and hyperadrenocorticism are two examples. Hypothyroidism, which is a lack of thyroid hormone in the body, can also cause sensitivity to cold, weight gain and fatigue. Hyperadrenocorticism, known as Cushing’s disease, is an endocrine disorder characterized by overproduction of a class of steroids called glucocorticoids. The disease may also cause increased appetite, thirst, urination, panting, high blood pressure and an enlarged abdomen.

A dog suspected of having either disease should have a thorough veterinary examination, including a complete blood count, blood chemistry panel and urinalysis. Both diseases usually respond well to medication.

Sarcoptic mange and dermatophytosis (commonly known as ringworm) can cause a dog’s hair to fall out in patches and the skin to be red and irritated. Demodex mites, which live in hair follicles, can cause hair loss but are typically not contagious.

Unless controlled, fleas, ticks, mites and lice can cause intense itching. Some dogs will itch and scratch until their skin becomes raw and the hair falls out. Check a dog’s stomach and the base of the tail for signs of fleas and their waste — it looks like tiny black specks — and ask your veterinarian about an effective method of flea control.

Loss of hair
Alopecia is complete or partial hair loss. It affects dogs with hypothyroidism and other hormonal imbalances or dogs who suffer a disruption in the growth of the hair follicle from infection, allergic reaction or trauma from excessive scratching.

Boxers, bulldogs, and Airedale terriers are at increased risk of recurrent seasonal flank alopecia in which hair loss and skin infection occur each year in late fall or early spring. The condition usually improves within six months, although the hair re-growth may be different in color or texture.

A condition called alopecia X or “black skin disease” is thought to be the result of a hormonal imbalance, although the cause of the hair loss isn’t entirely clear. In some cases, patients with alopecia are treated with melatonin, a human supplement intended as a sleep aid, to relieve symptoms.

It’s normal for a dog to shed and experience occasional hair loss, especially during the warm spring and summer months when the body rids itself of excess fur.

However, continual itching, scratching and biting as well as bald patches and noticeable hair loss aren’t normal and require veterinary care, Dr. Ackerman says. “The most important thing that owners can do to maintain a healthy coat for their dogs is to feed a good diet, perform regular grooming, do thorough home examinations of the skin to detect early problems and have regular veterinary visits to ensure that any medical problems are quickly addressed.”


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