Skin Allergies

Here are a few of the common reasons dogs lick and chew:

Your dog doesn’t have to be “loaded” with fleas to develop this condition. In fact, a dog that is hypersensitive to flea saliva will experience immediate itching and redness from only one bite. As the dog continues to bite and chew, it causes hair loss, skin abrasions and eventually develops a skin infection. This in turn makes the dogs itch even more. A common term for this is called a “hot spot.” If you suspect that your dog has a sensitivity to fleas the best thing you can do is prevent your pet from getting bitten in the first place. Have your veterinarian design a flea plan for your pet and stick to it year round. This should include eliminating the fleas from the environment as well as your pet. All animals in the house must be treated. There are good cost effective products like Advantage Interceptor, Sentinel and Frontline that are available from your vet. The key to choosing products for dogs with fleabite hypersensitivity is to choose products that will kill fleas on contact before they have a chance to bite. Depending on the severity of the symptoms, your vet may prescribe steroids, antihistamines, antibiotics, fatty acid supplements and medicated shampoos or topical treatment.

Inhalant allergies or hay fever in dogs is called atopy and is another common reason dogs will itch and lick themselves. Inhalant allergies, like in people, tend to be seasonal but unlike humans, dogs itch and lick instead of sneezing and watery eyes. There are tests available to help determine your pet’s allergies. Most general practitioners and all board certified dermatologists are capable of running the tests. Once the allergies are determined, you can then have allergy shots created for your pets. These are custom made vaccinations against the particular antigens that your pet is allergic to. The drawback is that only about 25 percent of all dogs treated get relief from the shots. An alternative is to treat with oatmeal shampoos and antihistamines to alleviate the licking. Long-term steroid use can have side effects and are usually avoided unless the condition is severe and alternative therapies are not effective.

Scabies is a, highly contagious, zoonotic skin condition of dogs and cats that is caused by the sarcoptic mite. This scabies mite is very small and can be transmitted either directly from the pet or by contact with objects or surfaces that an infected animal has come in contact with. This parasite can live for several days in bedding or on clothing.

The mite burrows under the skin, and causes severe itching, scabs and hair loss. The signs are generally seen on the elbows, hocks, abdomen chest and ears. In extreme cases, the pet may even have a generalized illness.

Diagnosis can sometimes be difficult as skin scrapings are often negative. Therefore, sarcoptic mange is diagnosed primarily upon history of exposure to other animals (generally two to six weeks before the skin problems develop) and by physical exam. Your veterinarian will want to differentiate sarcoptic mange from other conditions with similar signs, such as food or flea allergies.

Since it is difficult to find the mange mites, treatment for sarcoptic mange is based on your vet’s suspicion. If the pets signs resolve following treatment then the diagnosis is made based on response to treatment.

Treatment includes multiple dips to kill the mites, and medication for itching and any secondary bacterial infection. Ivermectin is given as injections, except to collies, and is repeated every 10 to 14 days until the mites are gone. When animals are dipped, the entire pet must be dipped including the pets face and ears and the pet cannot be allowed to get wet between treatments. Your veterinarian will choose the appropriate treatment for each case.

The scabies mite is not a natural parasite of people and because of this, they will only survive about three weeks on humans. This is because the mite cannot reproduce on the human host. People who come in contact with an affected animal may develop an itchy rash with small raised red bumps on their arms, chest, or abdomen. Most people end up at the doctors for treatment because this can be an extremely itchy problem.

Ringworm is not a worm at all, but a fungal infection of the skin. Its name comes from the sometimes ring-like shape of the ringworm lesion. This too can be difficult to diagnose in animals, as the lesions do not look the same from case to case. People can get ringworm from direct contact with an infected pet. They can also develop the disease after contact with surfaces that have been exposed to the infected person or pet.

Immunocompromising diseases or immunosuppressive medications pre-dispose an animal to ringworm and increase the potential for a more clinically severe infection. A high population density, poor nutrition, and poor management practices increase the risks of infection.

Signs may range from an unapparent carrier state to hair loss, which may be patchy or circular. The classic sign of circular hair loss is more common in cats but often misinterpreted in dogs. Scabs, crusting and mild itchiness are usually seen. Lesions usually develop four to 10 days after contact with the fungus.

Ringworm is diagnosed by a good medical history and an examination of the skin. Some strains will glow or fluoresce under a special black light called a Wood’s ultraviolet lamp. However, the absence of fluorescence does not rule out “ringworm.” It is diagnosed, definitively, using a fungal culture. A small number of hairs are plucked from the edge of a hairless area and placed into a container with special fungal growth media. This is then monitored daily for characteristic changes associated with growth of “ringworm” fungi.

Treatment involves the use of systemic or topical antifungal medications for several weeks. The affected animals should be quarantined in the household to prevent spread of infection. Other animals that have been exposed may be treated with antifungal medications as a precautionary measure. Rechecks, repeated fungal cultures and exams might be needed to assess the response to treatment.

Since ringworm is a zoonotic disease it can be spread from animals to humans. The disease in humans is often mild and self- limiting. Skin lesions are usually red and may be circular. Treatment consists of topical medication until all lesions have resolved.

Food allergies are a common cause of itching and account for about 15 percent of all allergic skin disease in dogs. In contrast to inhalant allergies, which cause dogs to itch during certain seasons, food allergies can cause itching all year round. Typically, pets don’t respond to antihistamines and other medications for skin allergies. Of course, some pets have food allergies along with fleabite sensitivity or inhalant allergies. These pets usually have severe symptoms if they are not treated.

The most common clinical sign of food allergy is intense itching, as previously mentioned, can last all year long and doesn’t respond to medication, even steroids. These dogs will constantly lick their feet, unlike humans, dogs itch when they have allergies. Sometimes skin lesions will occur but they vary in severity and location. Dogs with food allergy issues often get ear infections.

Dogs with food allergies are allergic to certain proteins or carbohydrates in pet foods. They can be allergic to more than one food substance. The best way to diagnose food allergy is called a food elimination diet and should only be done through the guidance of a veterinarian.

This diet consists of only one single source of protein and carbohydrate to which the pet has not been previously exposed. This diet must be followed exclusively for a minimum of 13 weeks. Dogs with food allergy will show improved signs as early as four weeks with resolution of all signs by three months. The key here is that the only things the pet can eat are these single sources of protein and carbohydrate. One piece of chicken will throw everything off. Once the clinical signs have resolved, introducing the original diet will bring about the allergic reaction usually within 10 days of restarting that diet.

To diagnose which ingredient is the culprit, you restart the elimination diet and once clinical signs have resolved start adding in single food ingredients and monitor for allergic reactions. The most common allergens include beef, chicken, fish, pork, lamb, egg, dairy, corn, wheat, soybeans, rice and potatoes.

Once the antigen is identified it must be removed from the animal’s diet. If present, any secondary skin infections should be treated using antibiotics. Concurrent flea allergies must also be treated.

Yeast infections are another common cause of itching in dogs. These pets usually have red itchy skin that has a distinct odor. There are many predisposing factors that contribute to the development of yeast infections. Pets with folds in their skin, hypothyroidism, compromised immune systems and chronic steroid use may all predispose an animal to developing yeast infections. Diagnosing yeast infections can be difficult because yeast is a common resident of normal skin in dogs and infection only occurs when there is an increase in population. Excessive scratching, increased moisture and excessive seborrhea can also cause an animal to develop a yeast infection. Your veterinarian can detect yeast infections using slides and a microscope and sometimes even a skin biopsy. There are several ways to treat yeast infections including topical and oral medication. Most pets will stop itching within one to two weeks after starting treatment. However, recurrence is common so your vet should monitor your pet closely.

So don’t let your itchy dog suffer any longer. If they are scratching excessively, take them to the vet right away. Try and find out what allergies they have and start treatment. Your pets will love you for it!
Please note, articles in the Animal Resource Library are for reference only, and are not meant to diagnose or treat any medical or behavioral issues your pet may be experiencing.