ALLERGIC SKIN DISEASE
Allergic skin disease, or atopy, is one of the most common problems we see in practice and one of the most irritating for pets and owners alike. Dogs and cats can develop an allergic reaction to any number of substances in the environment or to their food, even if they’re eating the exact same food they’ve eaten their entire lives. Common indoor allergens include house dust mites, kapok (used in stuffing for cushions and soft toys), detergents, carpet cleaning products, and kitty litter. Common outdoor allergens include grasses, pollens, molds, trees, and weeds. Food allergens commonly include chicken, beef, pork, dairy products and wheat. Sadly for those of us who live where winter rarely truly sets in for more than a week at a time, fleas themselves can cause year-round allergic skin disease in some unlucky cats and dogs.
The most common age for dogs to start showing signs of allergic skin disease is between 1 and 3 years, but they will occasionally begin to suffer even younger, especially if the culprit is food, and the symptoms can also begin later in life in certain circumstances. Some of the most commonly allergic dog breeds are terriers (West Highland Whites in particular), French Bulldogs, English Bulldogs, Pugs, and Golden Retrievers, but any dog can be affected. The itching a dog suffers when he is allergic can generalize over the entire body, but most commonly starts on the feet and face. We now also know that most ear infections in dogs are associated with underlying allergy. The affected areas will be red and itchy, and this will lead the dog to lick, scratch, or chew the area, and that behavior does further damage. Areas which are licked a lot will become reddish-brown secondary to a chemical reaction between the dog’s hair and the saliva. With continued irritation and inflammation, the skin may become thickened and more pigmented, so you may notice a blackening of the skin, especially on the dog’s abdomen. Oftentimes, by the time we see the pet, there is secondary bacterial and/or yeast infection present, and these infections need to be treated as well as the underlying allergy.
Diagnosing the problem is by a mixture of examination and tests. A full examination of the dog will be needed to see if the skin disease might be part of a bigger problem such as thyroid imbalances or even auto-immune conditions. Blood tests may be needed to rule out these conditions, as even the most thorough of physical exams doesn’t always give us a clear answer. In any itchy skin condition it is important to rule out parasites such as fleas or mites, and if a fungal infection is suspected, it must be ruled out through a fungal culture.
Once infection has been treated and parasites have been ruled out or treated, if the itching persists, allergic skin disease will be a chief suspect. There is frequently more than one trigger, and allergies can develop to substances that have been in the pet’s environment for years. If the problem is seasonal, it points strongly toward environmental allergens, like pollens and grasses, as the culprit. If the itching started at a very young age and is a year round problem, we’re more likely to suspect food as the trigger.
Because allergy testing and desensitization is not always possible (for a variety of reasons), or because your pet only needs treatment for a short time every year, medical treatment is often the option chosen for our allergic patients. A combination of antihistamines. omega-3 fatty acids, and special medicated shampoos is our first line of attack, but simply due to the canine’s unique metabolism, many will not respond favorably to antihistamines and we must try a different type of drug. There are several immunomodulating drugs that can be used, and we choose carefully for each patient. Some do well on a combination of a small amount of steroid with a small amount of antihistamine. Some do well on a drug called Atopica, some do well on the newest option called Apoquel, and some seem to need steroids (cortisone). We use steroids sparingly, knowing that long term use can be unhealthy for your pet, but when they are indicated and used responsibly, they can have a dramatic positive impact on your pet’s quality of life.
At Fountain City Animal Hospital, if we choose to identify the source of the allergic reaction, we run a blood test sent to a laboratory specializing in the evaluation of canine and feline serum for antibodies against hundreds of potential allergy-causing substances (allergens). Identification of the allergens is most useful if the allergen is something which can be avoided or removed from the pet’s environment. If avoidance is not possible or if many allergens are involved, then desensitization (usually over many months to years) using a serum specifically developed for your pet’s unique allergenic profile can be initiated.
Allergic skin disease is such an unpleasant condition for both animal and loving owner, we understand well the drive for an instant and long-lasting cure. Sadly, this is a condition that can take some time to get under control initially and often needs lifelong treatment. There is no silver bullet for allergic skin disease, so it takes a patient and dedicated owner to work with us to maintain the best quality of life for your allergic pet.