Monthly Archives: December 2010

Conjunctivitis

This is the common term used to describe the most common condition affecting a dog or cats eye. It is an inflammation &/or infection of the tissue lining the eyelids, but not the eyeball itself. It usually does NOT impair vision unless the conjunctiva is severely swollen and covers the cornea. It does NOT imply human contagious “pink eye“, which is an inflammation and infection of the white portion of the eye known as the sclera. Conjunctivitis usually is not a symptom of a more systemic problem either, but there are exceptions like jaundice, causing a yellowish tint to the conjunctiva and sclera, which is a symptom of liver disease. There are many causes of non-systemic conjunctivitis. They include foreign bodies that get into the conjunctiva, allergies from pollens, grasses, leaves, etc. and infections caused by bacteria, viruses or fungi. The most common symptoms may include some or all of the following: redness of the conjunctiva, swollen eyelids, and a clear watery or thick pus type discharge from the eye. Often there is excessive blinking and rubbing of the eye, and even a sticking together of the eyelids. When allergies are the cause, sneezing and coughing may also be a symptom. It must first be determined that the eye ball itself is not involved and that there is no injury to the cornea. This is accomplished by the veterinarian using a topical anesthetic and sterile dye to check the intactness of the cornea. Once it is determined that there is no injury to the eye ball or cornea, many times a tear production test is then performed. If all these tests are negative, and the diagnosis of conjunctivitis is made, the veterinarian decides if treatment with an ointment or drops is warranted, and if antibiotics alone or a combination of antibiotics and a steroid is the course of treatment. Also, if allergies are suspected, various oral steroid/antihistamines medications may be used to treat an underlying allergy. Of course, avoidance is the best medicine. Always keep your dogs or cats eyes clean with cotton and warm water. Make sure hair is not brushing against the eye itself, and never let your dog ride in the car with its’ head out the window. As with all medical conditions, but most importantly with the eye, get a diagnosis early rather than later. The eyes heal slowly but do heal. A general thumb rule is to treat the conjunctivitis for 3-5 days after they appear back to normal.

Atopy

This is the abbreviated term for Canine Atopic Dermatitis. Atopy is one of the most common itchy skin allergy problems in dogs caused by a disorder of the dog’s immune system. It is an allergy to substances called “allergens” that are inhaled by the dog. These allergens cause the immune system to over-react and release an abundance of histamines, which irritate the skin. Some of the more common allergens are: house-hold dust mite excrement, dander, mold spores, and pollens from trees, flowers and grasses. Atopy is the 2nd. most common disorder causing hypersensitive skin reactions, flea allergy is #1. Atopy is 3-4 times more prevalent than food allergies in dogs, yet most dogs with a proven food allergy, also have atopy. The most common symptom of atopy is “pruritis” (itching), usually around the face and paws in the beginning and then around the ears, armpits, elbows and groin as the dog gets a little older. Often the dog suffers from recurring ear infections, and also chew on their paws. Symptoms can begin as early as 5 months of age up to 3 years and may start out as seasonal, but as the dog gets older it may exist all year round. Secondary skin infection are very common and often the eyes become red and itchy too (conjunctivitis). The skin may become unsightly brown from saliva due to constant licking. Unfortunately, there is no cure for atrophy. There are treatments and desensitization by allergy shots, but no permanent cure. Avoidance of dust mites by keeping your dog off carpeting and beds, keeping the dog inside as much as possible during pollen season, washing and vacuuming the dogs bed often, and keeping the dog out of damp moldy places can be beneficial. The treatment of atopy is short term cortisone use, sometimes mixed with an antihistamine. Frequent bathing is also prescribed, but these are only temporary measures. Fatty acid supplementation also may help. One of the newest drugs is an immune system suppressing drug known as Atopica, initially used in human organ transplant patients. It is very effective but initially expensive as the dose is high. The best thing to do is try and identify the offending allergens. Allergy testing is best to do in the winter when there are no fleas, ticks or outside pollens to worry about. The testing is approximately 80% reliable, not 100%. Once the allergens are determined, a long series of desensitization injections are prescribed which gradually stimulates the immune system to build up antibodies and thus resistance to the offending allergens.

Vision & Hearing Capabilities of Dogs and Cats

We gauge our vision in a number of ways: ability to see color, detail, movement, depth of field and night vision. Like human eyes, canine eyes have rods and cones, but they have less cones than us and cones are responsible for color perception. In fact, dogs are considered red-green blind. They see more yellowish, white and various shades of blue. As far as detail is concerned, it is estimated that they have 6 times poorer detail vision than the average human. However, dogs have more rods and that gives them superior night vision, estimated 4 x better than us. A dogs sense of motion is also much better than ours. They can spot movement ½ mile away but can not see properly up-close, less than 1 foot in front of their nose, unless there is movement. In general, the longer the nose of the dog, the greater the field of vision. For example, the peripheral vision of a labrador is better than a pug. Cats are more like dogs than humans and are neither nearsighted or farsighted. But, cat pupils are unique. Their pupils can dilate to round quickly and let in a lot of light. They can see light at eight times dimmer illumination than a human. Their pupils can constrict into a slit also very quickly which allows good vision in daytime and night time, even better than a dog. But, cats eyes lose good focus and as such have detail deficiencies. They also have red-green color blindness, like dogs, and see more yellows, white and blues. The cat’s eye is more specialized to see in rapidly changing light which assists in their hunting ability, and they also depend much more on movement than up close focusing. As far as our pets hearing is concerned, both dogs and cats hear better than us, especially in the upper ranges. In fact, cats can hear almost one octave higher than dogs, and both can hear in the ultrasound level. Because of the shape of their ears and their ability to move them, cats and dogs can “funnel” sounds into their ears. In fact, depending on the breed, dogs have 18 or more muscles to control ear movement, and cats have many more than that, closer to 33 muscles, and cats can move each ear independently. Our pets basically live in a world much different than ours and fortunately with their intelligence, trainability, and astute hearing and vision, many of these wonderful attributes help mankind, especially in search and rescue missions, and helping the handicapped, for example.

Mange: 2 Types

This term is usually used to describe a skin disorder caused by microscopic mites within the skin layers and/or hair follicles. There are two types: Demodectic Mange, caused by the mite Demodex canis, and Sarcoptic Mange, caused by the mite Sarcoptes scabiei. There are very distinct differences between them: Demodectic Mange is NOT contagious to other dogs, cats, or humans, while Sarcoptic Mange IS VERY CONTAGEOUS to humans and other dogs. Both mites are microscopic but the demodex mite usually is in large numbers and easy to find, while the sarcoptic mite number is low and very hard to find. Both are diagnosed by the veterinarian doing a skin scraping and seeing the live or dead mites under the microscope. More differences: Demodectic Mange is an immune deficient dermatitis, meaning the dog has little or no immunity against it, and Sarcoptic Mange is contagious and any and all dogs and humans can get it. The skin also responds differently: with demodex there is slight hair loss in the early stages around the face and forelimbs with little discomfort or scratching. In neglected cases the dog can go bald and have open infected sores. Sarcoptes causes an intense itch, a lot of discomfort and redness of the skin. In the early stages, the edges of the ears are usually irritated and very sensitive. It also can progress to baldness and open infected wounds in neglected cases. The treatments are different also. Demodetic Mange require weeks of treatment including injections of a parasitocide, and medicated bathes and sponge baths and no isolation. Because Sarcoptic Mange is so contagious, the afflicted dog should be kept in isolation until treatment is completed. This may require only one good bath and dip and cleaning of the environment, especially the bedding. Once the live mites are killed and eggs washed away the dog can be removed from isolation. All animals in contact with this form of mange should also be treated. Reoccurrence of Sarcoptic Mange is rare but dogs with Demodex can come down with it again if the immune system is challenged; however, it rarely shows up in dogs over 3 years of age.