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What makes my pet itchy and how do I control the itch?

Canine Addict

Jan 23, 2002, 10:52 PM

Post #1 of 2 (2095 views)
What makes my pet itchy and how do I control the itch? Can't Post

What makes my pet itchy and how do I control the itch?

Pruritis is the name for itchiness that causes pets to scratch. Several chemical reactions occur in the skin that stimulate the nerves, causing the brain to feel the itch. We treat a scratching pet by attempting to eliminate these reactions at the source and controlling the body's response to them as well. Some of the chemicals involved in itching are prostaglandins, arachodonic acid (a specialized fatty acid) and leukotreines. By using treatments that inhibit the action of these factors at the skin level, such as antihistamines and fatty acid competitors, we can sometimes control the itching without using corticosteroids such as prednisone. If we work to control other irritating factors such as fleas, dry skin and secondary bacterial infections we can also further reduce itching. Each of these steps is very important because pets have an "itch threshold". This is the point where all of the sources of itching finally add up to enough irritation to cause the irresistible urge to scratch. Just like pain thresholds, these levels vary from pet to pet. Control of every possible factor is important to your dog's health and comfort.

Pruritis is a complication of many diseases. Only by careful examination, diagnostic tests and sometimes even trial and error can we come to understand what causes the itching in a particular pet and how we can best control it.

Stopping 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 arachadonic 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 8 weeks or longer to 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 in 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. Cortisones 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. Cortisones depress lymphocytes, a type of white blood cell, making it easier for bacterial infections to occur. Accidental overdosage 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, we insist on monitoring a pet on cortisones through follow-up office visits. We may ask that you allow us to examine your pet prior to refilling prescriptions for these drugs. In spite of these side effects, cortisones 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 medications and dosage schedule for your pet, but is worth the effort.

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Old Hand

Jan 31, 2002, 11:18 PM

Post #2 of 2 (2077 views)
Re: [Rainbow] What makes my pet itchy and how do I control the itch? [In reply to] Can't Post

Further information on the "itchy issue." Happy reading Smile


Most dogs at some stage of their lives will suffer from itchy skin. Dogs can show problems at any age, even as young as 3 months old. Allergies in dogs usually become worse with age and successive seasons.

So, it is important to try and get things under control as early as possible. Solutions are not always straight-forward and it can take time, as well as money and patience to see your pet better, but better they can get with a little dedication and perseverance. The most common hypersensitivities in dogs are fleabite hypersensitivity, atopy, contact allergy and food allergy.

Afflicted sites in patients with atopy or food allergy include feet, wrists, hocks, armpits, face, ears (may be the only sign) and tummy. Flea Allergy Dermatitis (FAD) is typically characterised by signs at the base of the tail, groin, tummy and thighs. Contact allergy affects the sparsely haired areas - tummy, groin, armpits, chin, skin between the toes (depending on the breed).

If the signs are worse in summer FAD and atopy are more likely. Itchiness limited to winter or spring is more likely due to atopy (dust mites in winter, pollens in spring). If the animal is itchy all year round, atopy and FAD are however, by no means ruled out.
Food and contact allergies are non-seasonal provided that the environment or diet does not change on a regular basis.

Flea allergy dermatitis
flea bite hypersensitivity The most common cause of skin disease in dogs (up to 80% of skin problems) but the easiest to solve is FAD. The dog's body reacts to the flea saliva which creates a strong itch. One flea bite can be enough for the poor dog to develop a strong itch for 2 weeks! You won't necessarily see the fleas when you look for them. You may see the flea dirt - tiny little black dots if you part the hair. Signs of FAD include hair loss, red bumps, crusts and occasionally bleeding but can be as mild as dandruff, and start at the base of the tail and lower back with the dog being very itchy.

Treatment involves treating both the dog (and any other pets you may have) as well as the environment. An appropriate monthly flea treatment and weekly shampooing as well as flea-bombs to treat the environment are essential. And remember prevention is better than cure!

- This is the second most common hypersensitivity in dogs. It is related to human eczema, asthma and hay fever. Atopy is an allergy caused by airborne irritants such as house dust mites, pollens, grass and mould spores, and cigarette smoke. Atopic dogs lick or bite their feet and lower legs, scratch their armpits, get ear infections and rub/scratch their tummies. Face rubbing and puffy eyes may be seen.
Dogs often lose their hair and get red, crusty skin that may bleed. After eliminating other causes, atopy can be diagnosed by way of an intra-dermal skin test carried out by a skin specialist. A tailor-made vaccine can then be used to slowly desensitise the dog. This is not a permanent cure but helps reduce the symptoms considerably. Vacuuming and keeping grass short in the garden can also help.

Contact allergy
- Direct contact is needed to initiate a contact allergy. Wandering jew (the most common culprit), grevillea, dandelion, wool, cement and sprinkled carpet deodorants can all cause clinical signs. A classic patch test carried out by your vet/skin specialist can help diagnose the problem.

The best treatment is avoiding whatever is found to cause your dog's contact allergy, although this is not always so simple. Wearing a cotton or lycra body suit and use of appropriate medication can also help avoid the problem. It is also well worthwhile to get rid of all wandering jew in your garden.
Food allergies are not seen as often as the previous 3 allergies. Food allergic dogs look very much like atopic dogs. An elimination diet (see your vet) can help diagnose the problem.

Demodectic mites can often cause dermatitis in puppies and old or debilitated dogs. This is not a contagious disease. Symptoms usually start with small, localised patches of non-itchy hairless skin around the eyes and face. In severe cases a dog can be affected all over (generalised demodicosis) with generalised hair loss and the skin suffering from secondary bacterial infection, redness and itchiness. Generalised demodicosis may be seen in animals whose immune system is compromised (eg suffering from another illness).

Demodectic mange can be diagnosed with a simple skin scraping test. Although needing persistent and at times intensive treatment which can take anywhere from several weeks to months, this condition can be effectively treated and the dog can completely recover.


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