Itch is the national pastime of the dog. The self-mutilation that can occur as a result, and in a short period of time, is often quite amazing.
Although there are many causes of itch, fleas are often either the immediate cause or amplify itching due to other causes. Among numerous other causes of itch are allergy, many times caused by inhaled allergens; self-directed immune responses (rheumatoid); liver problems; hormonal problems; and nervous reaction. Shedding is also a common and legitimate cause of itching which occurs particularly at the onset of warm weather, just at the beginning of flea season. Often external parasites other than fleas, and also intestinal worms, can increase the itch reaction.
The reaction that occurs to cause itch is complicated and not well understood. Many times there is an immunologic reaction that causes an accumulation of immunoglobins in the skin and an exudation of serum. This allows growth of skin bacteria which can stimulate further formation of immunoglobins at the site. A great interruption of the morphologic integrity of the skin results. Antibodies combine with antigen to cause many other reactions as well. Among them is the accumulation of mast cells and their production of other substances which cause itch. Further morphologic destruction ensues.
The immune system is very active in the protection of the body from invasion by many organisms and especially by whole animals (mites, lice, fleas, worms) on the outside or inside of the body. However, once the immune, morphologic and inflammatory changes occur, these changes, especially those of inflammation, stay in the area for long periods of time. At a site of inflammation, neutrophils (pus-cells) and lympohocytes (which produce antibody) accumulate and a good number remain, sometimes for years, to be ready for a similar invasion in the future.
What follows is an outline describing ways to deal with some of the more common problems which cause or intensify itch.
As stated above, shedding is a legitimate cause of itch. To ease an animal's discomfort and hasten the shedding process, a dermatolytic shampoo such as Selsen Blue or Seleen (the latter available at the hospital) can be helpful. Vaseline should be applied to the animal's eyes, anus, and scrotum or vulva, and cotton put in the ears. The animal should be thoroughly wetted and the shampoo lathered into the coat and, if possible, left there for ten minutes. The shampoo then must be carefully rinsed out. Once the animal is dry you will be able to brush out a surprising amount of hair.
It is also important twice a week to feed your dog or cat a dab of Vaseline to help carry hair through the digestive tract. This is particularly true when the animal is shedding. Cooking oils will not be effective because they will be digested. The feeding of Vaseline, however, should be separated from meals in order to minimize the loss of fat soluble vitamins. Most animals, if gently initiated, will consider this ritual a treat.
Worms can usually be detected by a simple stool sample analysis. To check for tapeworms, however, you must see the worm segments in the stool of your animal. Dogs acquire tapeworms primarily by eating fleas. Cats acquire tapeworms also by eating other animals. Whip worms are often difficult to find in the stool, making repeated analyses necessary. Heart worms are detected by a blood test.
Parasite eradication is necessary for the general well-being of your animal. In the context of this hand-out, it is necessary because parasites activate the immune system, making it more responsive to other stimuli which might cause itch. Internal parasites can be eliminated by worming and, in the case of hookworms, also by treatment of the premises. Because the premises cannot be treated for whipworms, an animal with whipworms must not be allowed in the area in which it had been defecating. In the case of tapeworms, the animal's housing must be rid of fleas. Fleas stimulate the immune system both by carrying tapeworms and more directly by biting an animal. It is easy to speak of eliminating fleas, and difficult to do it.
Use frontline spray or top spot liquid. This compound can provide lasting protection from fleas for up to 3 months after one application. A pictorial description of the application technique will be provided when you purchses this product at the hospital.
Fleas and their larvae live in small nooks and crannies. They live under pile in deep pile rugs, in crevices, under mattresses, on boxsprings, between the boxsprings and bed, and under the cushions on the couch and chairs. They live under the edges of rugs and outdoors under the porch, in dog houses, in crevices in the cement in the cellar, in the garage, and in places you wouldn't dream of living. In a 6 - 8 week life span one female flea can lay one thousand to several thousand eggs, which will hatch 2 - 14 months after being laid. The chances of a mutant developing in the resulting crowd of offspring is very good. Such a mutant offspring may then metabolize an insecticide being used on a dog or cat in its immediate environment. Fleas seem to congregate where animals sleep. When an animal sleeps it's immune system is more active. At this time the allergy or other immune response caused by the flea is more marked. Fleas want the animals to react. Reactive animals are the ideal host for the flea. Therefore, these areas are the most important when you spraying the house.
In the outdoor, cellar, or garage situations the area can be sprayed every 2 weeks with a 2% solution of Malathion. This substance can be bought in hardware and garden stores as a 50% solution and, by mixing 1 tablespoon Malathion with 1 pint of water, can be made into approximately a 2% solution to be sprayed about with an inexpensive hand sprayer.
In the house the odor of such a Malathion solution and the complexity of the sheltered environment call for different measures.
Spray Siphotrol Plus II
Frontline, which occupies a neurotransmitter receptor only in invertebrates, can be spray or the gel applied every 3 months on dogs and every month on cats. A brochure will supplied to you with this product when purchased at a veterinary hospital.
This product can be used prophylactically to keep fleas off your animals as well.
Flea shampoos kill fleas present on an animal when it is bathed, but do not prevent further infestation. Flea shampoos, however, are the best product to use on very young animals (up to 12 weeks of age). Vaseline and cotton should be used as described above, and the shampoo thoroughly rinsed out of the coat.
It is useless to treat your animal for fleas while neglecting to treat your animal's environment.
Itch is a difficult process to control. Corticosteroids are used to do this. Since these are man-made analogs of normal body adrenal hormones, the manipulation of their concentration in the body must be very well directed by a veterinarian. Once the acute problem has been controlled, a future "short course" of steroid administration can be used as soon as your dog shows signs of itching in the future. Cats have few itchy problems, but are subject to some other skin problems which need to be counteracted. The skin, as stated above, is often poised to begin reaction, including itch. It is frequently good policy to use a short corticosteroid regimen to control these potentially bad outbreaks at their beginning.
In addition to stopping various types of itch, it is often necessary to control infection that can accompany itch, either by administration of antibiotics or by clipping the hair in the area, and by soaking the area with hot clean water. If scabs exist it is best to keep them moist with Vaseline Intensive Care or hand creme so that the hot soaking will more easily lift the red or yellow (serum) scab. The itch of a loosening scab will not be controlled well with corticosteroids, but will be eased with hot soaks and cremes.
Allergies often can be "ridden out" because the time of the summer rapidly changes and the allergens dissipate. Anti-itch medication administered for a short period of time can help an animal ride out the storm. Some cases, however, demand an attempt at hyposensitization to the allergens.
To treat for itch with corticosteroids when there are fleas in the environment for any length of time is a ridiculous endeavor and, though the reasons are not clearly understood, can only become problematic for the animal's immune, inflammatory, and pituitary-adrenal systems. Look for flea feces (little black specks) in your pet's coat. These are the tell-tale signs of the rarely seen creatures that drive your animal wild.
This information is meant to help you with the problems you may be up against. There are many manifestations of these problems. Call and speak to a D.V.M. if things are not under control. Prevention and diligence are most important.
The skin is made up of 2 different layers of tissue. The outer layer, the epidermis, is derived from the ectoderm in the embryonic state and is devoid of blood vessels. It is dependent for blood supply and, therefore, nourishment, on the underlying tissue, the dermis, which is derived from mesenchyme, the same group of cells that produce connective tissue in the embryo. The epidermis is continually producing new cells from the basal cells along it's border with the underlying dermis. These new cells rise and later die, forming the keratin layer on the outside of the skin. However, the epidermal cells produced by the basal cell layer do not inherently know whether to grow downward toward the second layer, the dermis or outward toward the surface of the skin. The dermis takes care of this by not allowing downward growth of the epidermis. When conditions exist that cause an abnormal physiological state in the epidermis, as when antibody accumulates and infection occurs, the unmyelinated nerves at the junction of the underlying dermis and the epidermis are stimulated. The itch response tears off outer layers of epidermis and, it is hypothesized, further encourages growth of the epidermis from the basal cells. This increased growth outward implies also increased activity at the dermal-epidermal junction where the dermis must prevent downward growth of the basal cells. In other words there is always an underlying war between the dermis and epithelial cells.
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