Dermatological Disorders

Skin disorders are one of the most common reasons pets visit their veterinarians. Problems can develop wherever there is skin, including the ears, around the lips, the bottom of paws, and around the anus. Whatever the symptoms, problems with your pet’s skin are hard to ignore. Although the causes are varied, most skin problems make themselves known with one or more of the following signs: itchiness (scratching, licking, chewing, rubbing, scooting-dragging the bottom across the floor, shaking the head), sores, rashes, hair loss or a thinning coat, bumps, seeing fleas or ticks, or noticing a bad smell, even after bathing.


Common Disorders
Common causes of skin problems include parasites (fleas, ticks, mites and lice), atopy (an allergy to things breathed in or absorbed through the skin), food allergy, anal gland disorders (infection, impaction), infection/inflammation (abscesses, hotspots, scabs, ear hematomas, lick granulomas), and tumors (papillomas or warts). Underlying illnesses can also manifest as problems in the skin (i.e. endocrine diseases, cancer).
Parasites such as fleas and ticks can be seen directly on the skin. Fleas are tiny (about 1mm) and dark, and usually seen moving quickly on the skin when you part the fur. There is usually flea “dirt” (which is digested pet blood, the flea’s source of nutrition) seen on the skin and throughout the fur. Anytime flea dirt is found, there are fleas on your pet. Anytime there are fleas on your pet, there are or will soon be 1000’s of fleas in your house! Both fleas and flea dirt can be found easily by combing your pet with a flea comb (a comb with lots of closely spaced teeth). Ticks are variable in size, ranging from less than a millimeter to over a centimeter just after feeding.
Mites (Demodex, Sarcoptes) and most lice are too small to see and are diagnosed by your veterinarian using a microscope. Fleas, ticks and mites can transmit other diseases that can be zoonotic (diseases that affect people as well as animals) such as Plague, Lymes Disease, and Scabies. Most lice are species specific and usually do not transmit zoonotic diseases. They are gross, but do not usually cause medical problems for humans.
Another skin condition that can be seen in dogs, but is more often found on cats is ringworm, or dermatophytosis. Ringworm is not a “worm”at all, but a fungal infection. This is a highly contagious infection of the skin that is zoonotic (can be transmitted to people from animals) and causes a very itchy, scabby rash and hair loss, or sometimes no symptoms at all. One of the biggest problems with ringworm is that carrier animals (animals that have the fungal organisms in their fur but not the disease so there are no clinical signs) can transmit the infection.
Allergies to pollens, molds, organic fibers (wool) and other tiny particles found in our environment are extremely common in our pets. Dogs and cats can develop allergies to the same things which we are allergic. Instead of responding as we do with red, runny, itchy eyes, sneezing and sinus problems, our pets usually get itchy skin. They often lick their paws, chew at their skin or start to have problems with their ears (waxy buildup, redness, odor or just shaking their head a lot). Sometimes the only sign you may notice is the fur starts to turn colors, usually a rusty brown. This is due to your pet licking and chewing their fur or increased tearing from the eyes, both of which can indicate that your pet has developed an allergy.
Food Allergy
Food allergies can manifest similar to atopy, but often have added gastrointestinal signs such as vomiting, diarrhea or excessive gas. These pets may have chronic (long term, recurrent) ear infections and waxy buildup as the only sign.
Ear Problems
Because the ears are an extension of the skin, disorders commonly seen in the skin (allergies, infections) often affect the ears as well. Infections with bacteria and yeast can lead to odor, redness, discharge, pain and inflammation. Excessive shaking of the head and scratching at the ears can lead to an aural hematoma, a swollen external ear flap (pinna). Certain breeds (Cocker Spaniels) are prone to chronic ear problems due to excessive wax production and an exaggerated response to inflammation.
Anal Glands
Anal glands are normal scent glands located in the tissue around the anus. They contain a foul smelling material used by animals to mark their territory. Normally, the material is released when pets have a bowel movement. If stools are too soft, or your pet has been constipated, the anal gland material does not empty properly and can buildup inside the gland. This leads to itchiness, causing your pet to lick excessively, scoot across the floor (usually when you have company!), or sit down often with the tail tucked between the legs. Other problems seen when the anal glands do not empty regularly is that the material inside can become too thick. This can lead to a blockage and formation of an impaction or an infection. Signs that this has occurred include a bulge on either side of the anus at about 8:00 and 4:00 position, or you may actually see a small hole with bleeding or drainage, indicating that the gland has ruptured.
Skin infections can be secondary to many primary problems such as parasites, allergies, trauma (bites and scratches from fighting), and tumors. Signs include a rash that is moist and very red, and many small red bumps all over or in little patches. Sometimes you will notice multiple crusts and flakes with the loss of clumps of fur, or you may find a painful swelling or discharge. Usually, there is a bad odor associated with these lesions, a sign that there is an infection with either bacteria or yeast.
Inflammation is the response of tissues to trauma, and inflammatory lesions can be caused by parasites, allergies, or anything that leads to excessive licking, scratching, and self-trauma. Acral Lick Granuloma, or “lick sore” is a common skin disorder in dogs. A large firm, hairless, lump will arise, often on the feet or legs, in pets that constantly lick at the area. Eventually, the spot will become darkened (hyperpigmentation), and the skin becomes rough and thickened (lichenification). Sometimes boredom and anxiety are the causes.
In other dogs, the type of fur they have makes them at risk for developing inflammatory lesions between the toes or on the paws. Folliculitis (inflamed hair follicles), also called interdigital cysts by some, are seen commonly in Labrador Retrievers. They look like small red boils and are often quite painful, and can become infected due to excessive licking.
A tumor is a mass of tissue that grows independently from the tissue around it. It can be benign (does not spread to other areas, is stable) or malignant (spreads to other areas). Tumors of the skin are seen more commonly in dogs than cats. Some of the more common tumors seen include papillomas and adenomas which are benign skin growths and mast cell tumors which tend to be malignant (although Boxers tend to get benign mast cell tumors). It is difficult to identify a dermal tumor and determine if it is benign or malignant just by looking at it, this is often why your veterinarian may recommend surgical biopsy to help identify a tumor.
Autoimmune Disease
The immune system, that part of the body responsible for fighting off infections and keeping your pet healthy, can sometimes turn against itself. Autoimmune diseases (diseases where the body attacks itself) specific to the skin include a group of disorders known as Pemphigus. This disorder is characterized by bullous (bubble or bladder like), blisters and crusty pustules on the skin of the nose, paw pads, ears and lips. Another disorder is called Lupus. This disease causes the formation of ulcers, loss of color around the lips and eyes, and hyperkeratosis (over production of the top layers of the skin into a thick, horny growth) of the nose and paw pads.
Diagnosing the cause of skin diseases involves getting an accurate and thorough history. Your veterinarian must know your pet’s diet, including all treats given, medications, especially those OTC (over the counter) medicines and supplements you give, grooming products used, and travel history. It is very important to let your doctor know if your pet has been ill recently, and you should be prepared to give as much detail about the symptoms you are seeing as possible. If necessary, bring in labels of medication, supplements and different food or treats so that, together, you will both have as much information as possible to figure out what is going on. If more information is needed beyond the history and physical examination, your veterinarian may recommend blood tests to get information about the overall health and internal condition of your pet, skin scrapes, needle aspirate cytology (looking at cells under the microscope), biopsies, or cultures (growing bacteria in the lab and testing for sensitivity to antibiotics). In some cases, biopsies, special food trials or even a referral to a dermatologist for allergy skin testing may be recommended.


Treatment and Prognosis
The treatment of skin disease will vary, but will depend on treating the underlying cause at the same time as treating the secondary symptoms. Some simple treatments may involve using bandages or Buster/Elizabethan collars to prevent self-trauma. Most treatments will be based on test results, but often include parasite control (monthly flea/heartworm preventatives), antibiotics, or medicated shampoos and conditioners. Other useful treatments include anti-inflammatory drugs (drugs to decrease the redness/heat/pain/swelling response), antihistamines, topical ear cleaners and medicated drops, immune suppressive drugs (for autoimmune diseases and atopy), hypoallergenic diets (usually prescription pet foods with a limited number of ingredients) or dietary supplements (omega-3,6 fatty acids), or possibly surgery (to drain abscesses, hematomas, or remove tumors). Some newer treatments involving phototherapy (light therapy) and acupuncture have also shown success in controlling some of the more chronic disorders. In most cases, the prognosis is excellent for providing your pet with relief and restoring comfort, however most skin disorders involve control rather than cure. Because the causes are often chronic in nature, diligence, commitment and constant open communication with your veterinarian are critical to long-term success.