Cortisone Shots and Dog Allergies
Veterinarians provide dogs with cortisone injections, most often, when the pet is in a constant state of itching and scratching. The cause of this discomfort is most often an allergic reaction. Cortisone injections are also a common treatment for relieving pain in arthritic dogs.
- The allergic reaction that is causing the dog to scratch is a malfunction of the body's defenses. The cortisone suppresses the defenses, causing the itching to go away. Cortisone also reduces inflammation, making it helpful for with arthritis.
- Cortisone creates an anti-inflammatory effect similar to that of cortisol, which is a hormone produce by the body. The anti-inflammatory property is helpful in reducing inflammation and is the main reason it is given to arthritic pets.
- Cortisone will remain in the dog's system from 8 to 12 weeks after the injection. However, the dog may begin itching again--or experiencing pain associated with arthritis--as the levels of cortisone decrease, but are still present in her system.
- Cortisone causes increased thirst and increased urination in most dogs. It may also cause increased appetite, depression, hyperactivity, panting and diarrhea in many dogs.
- Cortisone affects the dog's liver, pancreas and adrenal glands. It also suppresses the dog's immune system.
By Bethney Foster
Treatment and Relief for the Itch
Cold water will usually reduce itching and produce temporary relief. It doesn't really matter how the water is applied, but it must be at least cool. This effect doesn't last long, usually less than one-half hour. Adding Episoothe Oatmeal Shampoo, Episoothe Oatmeal Creme Rinse, Aveeno Colloidal Oatmeal, Relief Shampoo or Domeboro's solution helps to prolong the effect. All of these products are available over-the-counter. If you use Aveeno, one to two tablespoons per gallon of water, applied as a rinse, works best. Follow the directions on the Domeboro packet and also apply as a rinse.
Shampooing will sometimes help to control itching. Some shampoos such as Pyoben and Oxydex, act to reduce the bacteria level on the skin, one cause of itching. Seba Lyt and other sulfer/salicyclic acid shampoos reduce scaling. Lytar, Clear Tar and other tar containing shampoos reduce itching and oiliness. An emollient or moisturizer used after shampooing will restore some moisture to the skin and this also reduces itching. Expar Creme Rinse can be used to kill fleas after itching and moisturize the skin.
Antihistamines are useful in the treatment of itching in some dogs and cats. Used alone, about 15 to 25% of dogs will respond to antihistamines. Used in combination with fatty acid inhibitors, such as DermCaps, EFA-Z and Omega EFA capsules, about 25 to 40% of dogs will respond, reducing scratching behavior to acceptable levels. Antihistamines available over-the-counter are Benedryl (diphenhydramine, 25mg capsules) and Chlortrimeton (chlorpheniramine maleate, 4mg tablets). There are prescription antihistamines, notably Atarax (hydroxyzine) that work better in some cases. It is necessary to get a dosage for your particular dog or cat from your vet.
Dogs and cats have individual reactions to antihistamines. Since some dogs will respond better to one than another, it is best to try more than one antihistamine before giving up on them to control itching. Some pets will become drowsy when taking antihistamines. If this is unacceptable, they can not be used, or might be best to use at bedtime. Occasionally a pet will get excited when given antihistamines. These pets should not be given these products.
Fatty acid derivatives compete with aracadonic acid, the trigger for itching in the body. By replacing this compound with an inactive competitor, itching can be reduced. It is important that the fatty acid derivative chosen have gamma-linoleic acid, eicosapentanoic acid, or both. These products work best at high dosage levels and when given with a low-fat canned food such as W/D, which is available through veterinarians. Although they can be fairly expensive, their use is preferable to cortisones if they are effective. It is necessary to use these products for at least 6 to 8 weeks to judge their full effect. EFA-Z and DermCaps are examples of these medications.
Antibiotics are used to control skin infections associated with scratching. The itching leads to scratching, which damages the skin. The damaged skin is easier for bacteria to grow in. The bacteria then contribute to the itching, leading to more skin damage. As this cycle progresses, deeper and deeper layers of the skin are affected, sometimes leading to systemic bacterial infections that can even be fatal. Control of skin infections with antibiotics takes time. The usual defense mechanisms of the body, fever, white blood cells and antibodies do not work as well on the skin surface. Antibiotics must do more of the work alone. For this reason, 3 weeks is the minimum recommended time that antibiotics should be given for skin infections. Often, antibiotics must be continued for up to 8 weeks to consistently control skin disease. Several antibiotics seem to work consistently in skin disease. When these antibiotics fail, it is necessary to culture the skin lesions to identify which antibiotic might be appropriate in an individual case. Occasionally it is necessary to continue antibiotic therapy indefinitely to control severe bacterial skin disease.
Some dogs appear to be unable to prevent penetration of staph (staphylococcus) bacteria into the skin. These dogs can be benefited by the use of a product to promote immune responses. Similar to vaccinations (but short acting), these products help the body learn to fight off staph bacteria. They are Staph Lysate and Immunoregulin. Although somewhat expensive and necessitating weekly injections, these products can cost less to use than frequent or continuous antibiotic therapy. We have better success with Staph Lysate.
Hyposensitization, or allergy "shots", are used in dogs. Their use in cats is very limited due to difficulties testing cats accurately for individual allergens. Similar to their use in people, these injections help many pets, but not all. To be used properly, it is necessary to identify the allergy agents affecting a dog and then treat accordingly. This can be done by skin testing, where small quantities of allergens (allergy causing agents such as pollens), are injected into the skin and the response to this monitored. Often, it is necessary for a general veterinary practitioner to refer a pet to a veterinary dermatologist for this testing. Recently, blood tests have been developed to allow allergy testing without injections into the skin. These have become better understood recently and are correlating with the skin testing fairly well, although it is generally agreed that skin testing is still more accurate. Allergy injections require a consistent effort from the pet owner. They are the preferred treatment for inhalant allergies if that is the only condition affecting dog, when effective. Currently, about 70% of dogs are thought to benefit from this therapy.
Fleas cause most the allergic reactions in pets. Flea control is essential to our success in treating itchy dogs. Please ask for flea control information if you have any problem at all with fleas on your pet!
When itching can not be adequately controlled by one of the above methods, we usually use a corticosteroid, such as prednisone. Cortisones are the most consistently effective anti-itch medications that we have. They do have several drawbacks, however. Cortisone's increase the amount of water your pet drinks, making it urinate more, too. Sometimes this becomes a problem. These drugs increase appetite and weight control can be difficult while using them. If proper dosage schedules are not followed there can be long-term side effects such as decrease in bone density or an increased chance of pancreatitis. Cortisone's depress lymphocytes, a type of white blood cell, making it easier for bacterial infections to occur. Accidental over dosage with these medications or inappropriate long-term use can lead to medication induced Cushing's disease, a cause of hair loss, muscle weakness and other problems. For these reasons, most vets insist on monitoring a pet on cortisone's through follow-up office visits. You may be required to allow examination of your pet prior to refilling prescriptions for these drugs.
In spite of these side effects, cortisone's can be the best drugs to make an extremely itchy pet comfortable. If they are the only effective drugs for your pet they are worth the small risk to an individual pet of side effects. These drugs are reasonably safe for long term use if given according to directions. Allowing your pet a good quality of life, by controlling the itching, is worth the small risk of using prednisone and related compounds.
These are the methods we use to treat pruritis, the itchiness that causes your dog or cat to scratch. It may take several tries to work out the proper drug and dosage schedule for your pet, but is worth the effort.
Mike Richards, DVM