Factors that may predispose your pet to develop otitis externa include ear structure (long floppy ears, heavily haired ears, long narrow ear canals), errors in treating or cleaning ears (aggressive use of Q-Tips deep in the ear canal), and diseases that obstruct the ear canal (growths, swelling of the ear canal tissue). Factors that usually cannot cause otitis externa by themselves but can be a significant problem in need of treatment are bacterial and yeast ear infections. Sometimes pets with chronic otitis externa have problems beyond the ear drum (middle ear—otitis media), and these problems also need to be aggressively treated.

Many factors may come together in development of your pet’s ear problem. Recognition and subsequent treatment of all factors are the keys to successful clinical management of the otitis externa.

What are the symptoms of atopic dermatitis?

Atopic animals usually rub, lick, chew, bite, or scratch at their feet, muzzle, ears, armpits, or groin, causing hair loss and reddening and thickening of the skin. In some cases, several offending substances can “add” together to cause an animal to itch where each individual substance alone would not be enough to cause an itching sensation. These substances include not only airborne allergens (e.g., pollens) but allergens in food and from parasites (e.g., fleas) as well. Itching can also be exaggerated by bacterial or yeast infections of the skin. Sometimes, eliminating some but not all of the problems, a pet’s itchiness may go away. Therefore it is important to treat any other problems that could be making your pet itch while dealing with allergy.

What tests are needed?

A variety of tests may need to be performed. These may include culture or microscopic examination of the discharge from your pet’s ear. In addition, blood testing or skin testing for allergy may be needed. A dietary change may be recommended to determine of a food allergy is the cause of your pet’s ear disease. X-rays of the skull can aid in diagnosing middle ear problems.

What treatment is needed?

One or more in-hospital ear cleaning procedures may need to be performed on your pet. This may be as simple as an ear cleaning requiring just a few minutes with no or minimal sedation to more involved ear cleaning requiring more time and general anesthesia.

Attaining the goal of complete resolution of your pet’s ear disease depends heavily on your ability to clean and medicate your pet’s ears, follow through with therapy based on the results of the various tests, and faithfully return your pet for serial reevaluations at your veterinarian’s clinic.

Recurrent otitis externa not managed properly can cause chronic irreversible changes in the ear canal, most notably a narrowing of the ear canal diameter. This narrowing does not allow medication or cleaning solutions into the affected area. Further narrowing will not allow the normal ear wax secretions to exit the ear canal. Even though your pet’s ear may seem to be improved (less discharge, less smell, less discomfort), the ear disease may not be completely resolved and premature discontinuation of therapy can be detrimental to the chances for final resolution of the ear problem.

Sometimes, the underlying problem cannot be found or corrected. In these cases, a maintenance cleaning and medicating protocol may need to be formulated for your pet. If this protocol is followed, many ear problems can be controlled with minimal time and effort on your part and minimal discomfort for your pet.

Appropriate cleaning is a vital part of the overall program to appropriately address ear disease. The ear canal should be thoroughly cleaned of all debris before any medication is instilled in the canal. Your pet may object to having its ears cleaned initially, but better acceptance usually occurs with time. If your pet’s ear canal is red and uncomfortable at the beginning of treatment, gentle but thorough cleaning will help. After filling the ear canal with the ear cleaning solution, massage of the canal will help loosen the debris and discharge. The debris can then be massaged up from the base of skull (where the ear meets the head) to a cotton ball that is seated firmly in the opening of the canal. This procedure should be repeated until no more debris is recovered on the cotton ball. Medication is then placed in the canal and massaged down to the base of the ear. Q-Tips should never be used to clean the ear, except on the very outer ear folds. The key to successful cleaning is being consistent and thorough.

Reevaluations at the clinic are also a vital part of successful clinical management. Your pet’s ears may appear normal to you but may need continued medication and cleaning for complete resolution of the inflammation or infection. In dogs with chronic otitis externa, a maintenance cleaning or medicating protocol may need to be formulated based on the information obtained from the reevaluation visits.

If the ear disease has progressed beyond the outer ear canals, past the eardrum into the middle ear cavity, aggressive use of topical as well as oral medication may be needed. In addition, surgery to access the middle ear area for cleaning and identification of any infection may be necessary.

What are the symptoms of food hypersensitivity?

Dogs and cats with food hypersensitivity may exhibit some or all of the following symptoms:

• Pruritic (itchy) year-round
• Gastrointestinal problems, such as vomiting and diarrhea
• Rubbing or scratching at the face
• Chewing at feet
• Recurrent skin infections
• Red, painful ears and recurrent ear infections

The onset of food hypersensitivity can be sudden and it will continue as long as the offending food source is ingested. Once a pet is allergic to a food product, it may take weeks to months for the symptoms to resolve once the allergenic food item is removed from the pet’s diet.

What testing is needed and what is the treatment?

Unfortunately, no reliable skin or blood test is currently available to diagnose food hypersensitivity. The diagnosis of food hypersensitivity requires that your pet undergo an elimination diet trial. An elimination diet trial is a challenging exercise for most owners and if it is not done correctly it will fail to provide the needed information to answer whether or not your pet has food hypersensitivity. An elimination is either homemade or a commercial prescription diet that contains a protein and a carbohydrate source that your pet has never been exposed to previously.

Alternatively, newer, hydrolyzed or low molecular weight diets contain more common ingredients that have been molecularly altered to be below the allergenic threshold. These and other diets used to diagnose food allergy are “veterinary prescription only” diets and must be used under the supervision of a veterinarian.

A home-cooked elimination diet in a ratio of one cooked pound of protein (fish, pork, tofu, pinto beans, rabbit, and venison) to 6 cups carbohydrate (potato, oatmeal, rice, tapioca grain, but not the packaged pudding mix) can be considered if owners are able to cook for their pet. Most pets can be fed daily about a cup of this diet for every 10 pounds of body weight. A home-cooked diet allows preservatives and other food additives to also be avoided during the elimination trial. A home-cooked diet is not usually nutritionally balanced for long-term use.

The elimination diet trial must be completely strict. Potential pitfalls to avoid during the diet elimination trial include the following:

• Your pet cannot have any treats of any kind, including rawhide, pigs’ ear, or other animal-product chew toys.
• Your pet cannot be given any flavored vitamin products or flavored heartworm preventative or use toothpaste or other flavored medication or products. Be sure to discuss all medications or supplements you might give to your pet with your veterinarian. Some may need to be discontinued during the elimination diet trial or your veterinarian may prescribe non-flavored alternatives to give during the elimination diet trial.
• You cannot use cheese, hot dogs, or any other food item to hide medications.
• Outdoor dogs and cats that can roam may need to be kept confined to ensure that they are getting nothing to eat except the diet chosen for the diet trial.
• If there are multiple pets in the household it is vital that you are sure that there is not an opportunity for the animal undergoing the elimination diet trial to have access to another animal’s food, treats, toys, or medication(s).

Switching to a new diet should happen gradually over several days by feeding more of the new diet and less of the old diet each day. Cats can be particularly challenging to get to accept a trial diet. It is important to not allow your cat to go more than 48 hours without eating. It may be necessary to try several different diets before your pet finally accepts a trial diet. Once your pet has transitioned onto the trial diet your pet should only be allowed to eat the prescribed diet and to drink water. NOTHING ELSE SHOULD PASS YOUR PET’S LIPS.

It is useful to keep a diary of any changes you may note during the diet trial. These changes may include changes in the following:

• Appetite
• Elimination
• Scratching
• Appearance of the skin
• Appearance of the ears
• Weight changes

In addition, record any instances when the pet may have cheated by consuming food items not permitted during the food trial. The diet trials usually continue for 8 to 12 weeks, at which point you should have your pet re-examined and discuss any observations you have made during the elimination diet trial with your veterinarian. Your pet may not have 100% resolution of clinical signs during the elimination diet trial yet still have food hypersensitivity. Animals with food hypersensitivity may continue to exhibit some degree of itchiness during an elimination diet trial if they have still had access to the offending food item, if they have concurrent secondary skin infections, or if they have concurrent other skin allergies.

To confirm the presence of food hypersensitivity, a re-challenge with the original diet is performed. You will be instructed to begin feeding your pet the original diet plus any treats or food items that were routinely fed to your pet prior to starting the elimination diet trial. If your pet is food allergic, the clinical signs, specifically itching, should worsen within hours to days of beginning the previous diet. Most animals with food hypersensitivity will experience an exacerbation of their clinical signs within 2 weeks of being fed their previous diet. Should this occur, your pet would need to be fed the elimination diet again. Once the clinical signs have again resolved (usually very rapidly), your veterinarian will instruct you as to the next step in discovering the offending allergen. The good news is that if your pet has food hypersensitivity, so long as the offending substance is eliminated from your pet’s life this will decrease or control the clinical signs.

Many pets with food hypersensitivity may have an “allergic personality.” This means that they may also be predisposed to other allergies, such as flea allergy dermatitis or atopic dermatitis (environmental allergens, i.e., pollens, molds, house dust). It is strongly recommended that all pets with suspected or confirmed food hypersensitivity be kept on strict flea control and be monitored closely for the development of secondary skin infections, increased itching or other evidence of a concurrent allergic dermatitis. However, with food hypersensitivity controlled, your pet’s itch threshold will be substantially reduced, allowing your pet a more comfortable and higher quality of life.

In the dog, the most commonly observed symptom of flea allergy include biting and scratching around the rump, tail base, and groin areas, the creation of “hot spots;” and the development of secondary skin infections. Cats may manifest flea bite allergy more subtly. You may see many areas of hair loss and scratching, but more often you will feel small scabs and bumps around their neck and down their backs (military dermatitis).

It may seem confusing to be told that your dog or cat has flea allergy dermatitis if you never see fleas. This is mainly due to the fact that your pet has a remarkable capacity to chase and subsequently eat these fleas! You may find evidence of fleas on your pet by using a fine comb and brushing out the “flea dirt” that they leave behind. This “dirt” looks like small black dots and is the excrement of the flea. When placed on wet paper, it dissolves in red streaks since it contains partially digested blood. The adult cat flea spends most of the time living on cats and dogs. Fleas will lay eggs on the animals, but these eggs will rapidly fall off the pets and be distributed in the parts of the environment where the animals spend most of their time. The eggs will hatch into larvae; larvae evolve into pupae (cocoons) that emerge later as adult fleas. For one adult flea found on your pet there are at least one hundred immature fleas in the animal’s environment.

Flea Control on Your Pet

The only long-term effective and safe therapy for flea allergy dermatitis is to keep your pet from being bitten by fleas. This may seem like an impossible task, but it is not. Successful resolution of the flea allergic animal’s discomfort requires that you do everything possible to minimize the number of fleas that can contact your pet. Flea control must involve all areas of infestation. This means killing the fleas on your pets and in your house and yard. Treating only once kills the adults and some pre-adults, but will result in reoccurrence of infestation once the resistant eggs hatch or pupae leave their cocoons. The control of fleas is an on-going process, but once initiated, it is not difficult to sustain. The flea control program you use must be tailored to your individual situation.

Dogs

The use of an adulticide product for flea-allergic pets or households with flea-allergic pets is the most important part of flea control. There are several new “spot-on” formulations available that offer more convenience of application. These products have been shown to be effective when used as instructed and are not absorbed into your pet’s bloodstream, (they stay in the skin), making them safe. Advantage (imidacloprid), Advantix (imidacloprid and permethrin), and Frontline Plus (dipronil and methoprene) are currently available. Accurate dosage is based on the pet’s weight.  These products are applied by parting the hair between the shoulder blades down the back, and applying the small amount of liquid to the skin. Application frequency varies with the product and an individual pet’s bathing needs but most are applied every 3 to 4 weeks. Advantix cannot be used on cats. Revolution (selamectin), is a “spot on” product that is absorbed into the body. Revolution also provides protection against heartworm, scabies mites, and a variety of intestinal parasites in addition to protection from fleas. Reapplication is recommended monthly. A recently available, oral flea adulticide, Capstar (nitenpyram) is a safe, short acting, oral tablet that can be given whenever fleas are seen on the pet, or when the pet will be in a high-risk area. Capstar is safe to use daily but is designed for use as a “rescue” drug to kill fleas should they be seen. The use of a pyrethrin-based daily spray or foam product such as SynerKyl or Ectofoam may be recommended for your pet. These products are used when animals are being bathed often with therapeutic shampoos or are frequent swimmers. Pyrethrin sprays and foams, although extremely effective and safe, have little residual effect. These products may also have some repellent activity. If you have several pets and only one is allergic, the pets in your household must receive flea control to help control the clinical signs of flea allergy in the affected pet.

Cats

If you own cats, they must be involved in the flea control program even if they are not exhibiting any problems, or they will carry the fleas to your house, yard, and dogs. Cats are much more sensitive to the chemicals in flea preparations, and organophosphates and high concentration permethrins cannot be used on them. For cats we recommend using Frontline Plus (fipronil and methoprene), Advantage (imidacloprid), or Revolution (selamectin) in the feline formulation. They are applied in a similar fashion as in dogs. Beginning at the base of the head, part the hair and spread the small amount of liquid down the top of the neck. Capstar (nitenpyram) is also safe for use in cats as a “quick kill” in the event fleas are seen.

Juvenile Flea Stages

Several life stages occur before a flea becomes a biting adult. These juvenile stages are an ideal area to target for flea control. Decreasing the numbers of immature (juvenile) fleas can be an excellent way to help prevent adult fleas and thus flea bites. Recent research has led to development of several products that interrupt the life cycle of the flea. Synthetic juvenile flea growth hormone imitators are found in many flea products. Methoprene is contained in many of the indoor area treatments. Also available now is photo-stabilized Methoprene for outdoor use. Knockout collars contain pyriproxifen, a similar flea growth regulator that is effective for 13 months. Unlike other flea collars, these collars can control the juvenile flea stages and are quite effective and convenient. All of these synthetic hormones are safe to use on animals and around humans. They prevent the adult female flea from laying viable eggs and prevent immature fleas from developing into adults. Lufenuron (Program) is a pill available for both dogs and cats that is given monthly with food. As the adult female flea feeds on the dog or cat, she lays eggs that cannot hatch and larvae that will not survive. This product is safe, but flea-allergic animals also need protection from the biting adults. When used properly, it may take several months for the flea problem in your environment to be eliminated unless you combine the use of a product on the animal. Another formulation available is Lufenuron in combination with a monthly heartworm pill (Sentinel).

Many other forms of flea control on your pet have been scientifically shown to be ineffective. Flea shampoos will only kill the adult fleas but have virtually no residual effect and will not prevent re-infestation once they are rinsed off. Flea collars alone are ineffective because they are not able to sustain high enough concentrations of insecticide over the animal’s entire body. Electronic flea collars, brewer’s yeast, garlic, vitamin B tablets, and extracts of eucalyptus, tea tree oil, or pennyroyal are not flea repellent and provide no protection for your pet. Lastly, flea combs, although helpful, are similar in effect to the use of flea shampoos alone; they do not prevent re-infestation.

Signs of Toxicity

All flea control products are potentially toxic or may produce unexpected side effects. Toxicity may result from accidental overdose or unexpected sensitivity. Not all products safe for dogs are safe for cats; read labels closely! Known side effects, particularly to organophosphate pesticides, are vomiting, diarrhea, drooling, sluggishness, weakness, or abnormal behavior. If you suspect that your animal is reacting adversely to a flea control product, stop using the product and consult your veterinarian immediately. If the reaction occurs immediately after application, the product should be rinsed off thoroughly and your pet should be brought to the veterinarian for evaluation. Adverse reactions may occur from minutes to days following application. Insecticides can be toxic to people; all products should be handled carefully, avoiding direct contact as much as possible. Keep all products out of the reach of children. Cats may occasionally exhibit various degrees of hypersalivation (drooling) as a result of a reaction to alcoholic components present in some flea sprays. In case of doubt, please consult your veterinarian.

Flea Control in Your House

House treatments need to be concentrated on “source points,” which are areas where your pets spend most of their time. This typically would include the bedding areas, the paths between the rooms, the feeding location, etc. You may choose to utilize a professional exterminator service for the treatment of fleas in your home. The exterminators should use a combination of an adulticide to kill the adult fleas as well as an insect growth regulator for the juvenile stages such as methoprene or pyriproxifen.

If you choose to do your own environmental control, a premise spray, which contains an adulticide and an insect growth regulator is recommended. These products need to be used in all areas of the house where the pet(s) reside. Flea bombs and foggers may be inadequate as they do not go around corners or under furniture – places where the fleas hide. The control of fleas in the house should be repeated as instructed on the product label. Other ways to lessen the flea burden in the home include thorough vacuuming of all source points in the house followed by disposal of the vacuum bag and washing all animal bedding weekly in hot water with drying at high heat for 20 minutes.

Flea Control in Your Yard

In environments that permit year-round flea survival and reproduction, if the use of products on the animal have been insufficient to control the problem it may be necessary to treat the yard. It is important to principally focus on areas where your pets spend most of their time and where immature fleas may develop. Typically, fleas survive and reproduce in shaded, moist areas that contain plant or organic debris (under the decks, bushes, etc.). Fleas do not reproduce well in sunny, open areas of lawn or patio. Either a professional exterminator or you must treat for fleas in your yard. You can treat the yard yourself by purchasing Malathion or diazinon from your local lawn and garden center. Yard treatments with these chemicals should be performed as instructed on the product label. Another product available for outdoor use is a parasitic nematode (Bioflea) that can be applied to areas of damp soil. These nonpathogenic worms will seek and destroy flea larvae. Label directions must be followed closely for these to work.

Special Considerations

Households with small children, pregnant women, or debilitated individuals should not use the organophosphate family of insecticides. The pyrethrin-based products as well as the insect growth regulators for juvenile stages and the newer spot-on treatments are appropriate in these situations. However, no matter how safe the product or situation is, all pesticides need to be used correctly. The type of chemicals used environmentally may also be modified. Strict cleanliness, such as daily vacuuming, steam cleaning of rugs, and elimination of yard debris will be helpful to reduce flea numbers. As a reasonable precaution, pregnant woman and small children should never be involved in the application of chemicals on animals. Professional exterminators, with appropriate modification of their programs, are highly recommended for all treatments in these households.