Inherited skin disorders

Lymphedema

roblib — Mon, 22 Mar 2010 17:27:59 +0000

What is ... ?:

Lymph is a clear watery fluid that is collected from tissues throughout the body and returned to the blood by way of the lymphatic vessels, as part of normal circulation. In lymphedema there is abnormal lymph flow, so that lymph fluids accumulate and cause swelling in the affected tissue.

Primary or inherited lymphedema is caused by abnormal development of the lymph vessels or nodes and has been reported in the breeds listed below. Secondary lymphedema can occur in any breed if there is obstruction of lymph vessels due to tumours, inflammation, surgery, etc.

How is ... inherited?:

In some breeds, the mode of inheritance has been shown to be autosomal dominant with variable expressivity.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

The hind legs are most commonly affected, although front legs, abdomen, tail and ears can be affected too. The skin looks normal but has a thickened spongy feel, and if you press it, your fingers will leave dents.

Skin that is swollen due to lymphedema is susceptible to bacterial infection and delayed healing after injury, but otherwise your dog will be generally healthy.

How is ... diagnosed?:

Diagnosis is made based on physical examination and tests to rule out other causes of edema.

How is ... treated?:

Mild cases of lymphedema may come and go, or persist without any adverse consequences for your dog's health. Soft compressive bandages may be required to reduce the swelling due to fluid (lymph) build-up, and antibiotics will be required in the case of infection.

For the veterinarian:

Primary lymphedema is most commonly seen in puppies or young dogs as pitting, non-painful edema in the pelvic limbs. Pain usually indicates secondary infection.
Rule out other causes of obstructive, inflammatory, and hypoproteinemic edema.

Breeding advice:

Affected animals and their close relatives should not be bred.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Bonagura J. Lymphedema. In: Côté E, ed. Clinical Veterinary Advisor Dogs and Cats. Missouri: Mosby Elsevier, 2007:648-650.

Growth hormone-responsive dermatosis; adrenal sex hormone responsive dermatosis

roblib — Wed, 31 Mar 2010 18:21:19 +0000

What is ... ?:

With this condition there are skin changes due to a lack of growth hormone (somatotropin). This hormone is secreted by the pituitary gland and is necessary for hair growth and the maintenance of normal elasticity of the skin. Affected dogs have varying degrees of hair loss and darkening of the skin, but are otherwise healthy.

Adrenal sex-hormone dermatosis is a clinically similar syndrome that appears to be due to abnormal sex hormone production by the adrenal glands, causing secondary changes in growth hormone levels.

How is ... inherited?:

A mode of inheritance has not been established; however the disorder is mostly seen in the breeds listed below.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

This condition is more common in male dogs between 1 and 5 years of age, with hair loss usually starting at puberty. Adrenal sex-hormone dermatosis is seen in males and females, either neutered or intact.

Hair loss (called alopecia) is symmetrical over the trunk of the dog and the skin is markedly darker in color due to increased pigmentation. Without treatment, hairlessness and hyperpigmentation will eventually spread over your dog's body except for head and feet. The condition does not affect the health of your dog, only his/her appearance.

How is ... diagnosed?:

There are several possible hormonal causes of hair loss in dogs. Your veterinarian will do tests to determine the cause in your pet.

How is ... treated?:

As mentioned, this condition does not affect the health of your dog, only his/her appearance. It can be treated with growth hormone (GH), but this is expensive and can be difficult to obtain. Treated dogs must be monitored for the development of diabetes mellitus which is a potential side effect of GH therapy. Castration may resolve the condition in male dogs.

Similarly, neutering of affected male or female dogs may help to treat adrenal sex-hormone imbalance. If ineffective, there are medical treatments that may be beneficial (opDDD or mitotane, and ketoconazole).

For the veterinarian:

Other endocrinologic causes of alopecia (hypothyroidism, hyperadrenocorticism) should be ruled out. Assessment of growth hormone or serum insulin-like growth factor (IGF) in response to a growth hormone stimulant such as xylazine or medetomidine is available in some laboratories [check with your diagnostic laboratory].

In adrenal sex-hormone dermatosis, elevations in sex hormone levels are seen post- ACTH stimulation.
Histopathologic changes are non-specific - normal to decreased skin thickness with atrophy of follicles, with or without a loss of elastin fibers.

Breeding advice:

Although little is known about the inheritance of this disorder, it is prudent to avoid breeding affected animals or their close relatives.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Schmeitzel, L., Lothrop, C.D., Rosencrantz, . 1995. Congenital adrenal hyperplasia-like syndrome. In J.D. Bonaguara and R.W. Kirk (eds.) Kirk's Current Veterinary Therapy XII Small Animal Practice. p. 600-604. W.B. Saunders Co., Toronto.

Perianal fistula

roblib — Fri, 16 Apr 2010 17:33:15 +0000

What is ... ?:

Perianal fistula is a painful, chronic condition in which single or multiple ulcerated tracts develop in the tissue around the anus. No one clear cause has been established, although many have been considered. Some of the factors involved appear to be a broad tail base and low tail carriage, and an increased density of sweat glands in the anal region. It is these sweat glands that become inflamed and infected, leading to the draining sinus tracts typical of this condition.

How is ... inherited?:

unknown, but there is a strong breed predisposition for the breeds mentioned below.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

This condition is painful for your dog. The types of signs you will see include straining or pain with defecation, bleeding, constipation, fecal incontinence, licking of the area, and malodorous anorectal discharge. These signs worsen as more tissue in the area around the anus becomes affected.

How is ... diagnosed?:

Diagnosis is usually straightforward, based on your description of what you observe in your dog, and on physical examination in which your veterinarian will find single or multiple areas of ulceration and draining tracts, with pus and blood. Your veterinarian may also take a skin biopsy if s/he suspects a tumour in the area (which usually has a more raised appearance, but can also be associated with extensive ulceration).

How is ... treated?:

This is a difficult condition to treat. Medical treatment (combination of antibiotics, antiseptics, and anti-inflammatory drugs) only provides temporary relief, and is usually not successful in clearing up the condition. Generally surgery is required, and there are several methods used including surgical removal of the tracts, freezing or cautery of the tissue, and tail amputation. Possible post-operative complications include significant bleeding, fecal incontinence, and recurrence of the tracts.

In mild cases, surgery often results in complete resolution of the problem, without recurrence. Where the problem is more severe (more tissue destruction), there is a lower rate of success and a higher occurrence of complications. Your veterinarian will discuss all this with you when considering what is best for your dog.

Breeding advice:

Although the inheritance (or even the cause of the condition) is not understood, it is preferable not to breed affected animals.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Atopy

roblib — Fri, 16 Apr 2010 18:37:23 +0000

What is ... ?:

Atopy can be considered the canine equivalent of hay fever. It is quite common, affecting around 10 per cent of dogs. Animals with this condition become sensitized to substances (allergens) in the environment, that are inhaled or absorbed through the skin (and which cause no problems for non-atopic animals). The resultant allergic reaction is primarily seen as extreme itchiness (pruritis).

The main allergens involved are house dust mites, house dust, human dander, feathers, molds, and pollens from trees, weeds, and grasses. Atopic dogs are also prone to seborrhea, secondary bacterial skin infections (pyoderma) and probably yeast (Malassezia) infections as well

How is ... inherited?:

The exact mode of inheritance is unknown. There is a strong breed predilection for this condition, and marked familial involvement (ie. if both parents are allergic, there is a very strong likelihood the offspring will be as well).

What does ... mean to your dog & you?:

The condition is usually first seen between 1 and 3 years of age, although it may develop as late as 6 or 7. Initially atopy may be seasonal (eg. from spring to fall) but most affected dogs eventually have signs all year round.

Dogs with atopy are very itchy. The areas most affected are the face, paws, lower legs, groin, and, less often, the ears and eyes. In addition to scratching themselves with their hind feet, they often lick or chew the affected areas, or rub along the carpet to scratch the face or ears. The intense itching can make them irritable and less tolerant of being handled.
Initially, there are no apparent skin abnormalities, except possibly slight reddening, even though the dog is clearly itchy. (This is important because in other conditions there is often a rash or some visible lesion.) Over time, lesions develop as a result of the scratching and self-trauma, bacterial or yeast infections, and seborrhea, all of which can contribute to the objectionable odor of these dogs. The skin becomes reddened and eventually darkened (hyperpigmentation), abraded, thickened, and wrinkled, with loss of hair and bronze staining from saliva.
The concept of "allergen load" is important in understanding and treating this disorder. Atopic dogs are generally allergic to more than 1 agent. A small amount of allergens may be tolerated without developing a reaction, but an increase in any one of those (ie. an increase in allergen load such as occurs during pollen season) may push your dog over the edge to an allergic reaction of extreme discomfort.

How is ... diagnosed?:

There are many skin diseases that cause itching, and they can all look rather similar on physical examination. Your veterinarian will ask you questions about your dog's diet, environment, any kind of skin care you are already providing, whether any other pets or people in the house are itchy, where and how quickly did the skin lesions start, and is there any seasonal pattern to the itching. The answers, as well as the age and breed of your dog, will provide diagnostic clues. For example, itching that begins suddenly and rapidly gets worse, is more typical of a flea allergy, scabies, or a drug hypersensitivity. Itching that begins insidiously and gradually worsens, is seen more often with atopy, food allergy, bacterial or yeast skin infection, and seborrhea. Skin infections and seborrhea commonly develop secondary to atopy and may have to be cleared up before your veterinarian can diagnose atopy.

Diagnostic tests may include multiple skin scrapings and smears (for mites or yeast infection), fecal examination (for parasites), skin biopsy, skin testing (for allergies to different substances), elimination diets or change in environment (if food or contact allergy is suspected),

How is ... treated?:

Atopy can be satisfactorily controlled in at least 90 percent of affected dogs. There are 3 components to successful treatment, which will be life-long and will likely require modification from time to time. A combination approach is generally most effective.

1 reduction in exposure to allergens. This requires identification of the substances to which your dog is sensitive (ie. allergy testing). You may be able to avoid some allergens altogether (if your dog is allergic to feathers or tobacco smoke for example), and reduce exposure to others (by keeping your pet out of carpeted areas to reduce house dust mite exposure for example). Your veterinarian will discuss this with you, in conjunction with the results of your dog's allergy testing.
2 hyposensitization (immunotherapy or "allergy shots"). This is recommended when the allergens involved can't be avoided, and your dog has clinical signs more than 4 to 6 months of the year which can not be kept under control with medical therapy. Immunotherapy is carried out after your dog's allergens have been identified by allergy testing. Injections of low doses of the appropriate allergens are given at short intervals at first, and then boosters given as needed when clinical signs begin to reappear.
3 medical treatment. Long term management may include gentle moisturizing anti-pruritic (control itching) shampoos, fatty acids, antihistamines (more likely effective when given as preventative), and short-acting corticosteroids on alternate days (given for short periods at times when there are flare-ups, to mimimize the potentially serious side-effects).

For the veterinarian:

A tentative diagnosis can be made based on history, physical exam, and laboratory tests to rule out other possibilities. Intradermal testing (and to a lesser extent, serologic allergy testing) is necessary for definitive diagnosis and identification of allergens involved. Diagnosis should not be made based solely on intradermal (because of low specificity) or serologic testing (very common false-positive reactions).

Intradermal testing is the preferred method of diagnosing canine atopy and determining appropriate immunotherapy. However to get good results requires experience, practice, and close attention to detail. Many factors can lead to false-positive and false-negative reactions. Where possible, it is desirable to refer cases to specialists in this area.

Breeding advice:

Although the specific mode of inheritance is unknown, it is best not to breed affected dogs, their parents, and preferably their siblings as well, given the strong familial predisposition to this condition.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Immunologic Skin Diseases. In Muller and Kirk's Small Animal Dermatology. p. 500-518. W.B. Saunders Co., Toronto. This reference contains detailed information on allergy testing and on hyposensitization. Page 515 has practical suggestions for environmental management in atopic dogs.

Ihrke, P.J. 1995. Pruritis. In E.J. Ettinger and E.C. Feldman (eds.). Textbook of Veterinary Internal Medicine, pp. 214-219. W.B. Saunders Co., Toronto.

Bullous pemphigoid

roblib — Fri, 16 Apr 2010 18:52:33 +0000

What is ... ?:

This rare condition is an autoimmune disorder, meaning an abnormal immune response to a normal component of the body - in this case a protein in the skin. This results in blisters and ulcers in the skin and/or mouth. The disease is often severe, depending on how widespread are the affected areas.

This condition is very similar to bullous pemphigoid in people.

How is ... inherited?:

Inheritance is unknown.

What breeds are affected by ... ?:

Collie (rough and smooth)

What does ... mean to your dog & you?:

The blisters that occur with this condition are very short-lived, so you and your veterinarian are more likely to see ulcers. These lesions are found in the mouth and skin, particularly in the underarm and groin area. There may also be ulcerated areas around the nails or footpads. Your dog's skin may be itchy or painful, and it is common to develop a secondary bacterial infection (pyoderma). Dogs that are severely affected may lose their appetites, run a fever, or become depressed.

How is ... diagnosed?:

Your veterinarian will diagnose this condition based on physical examination of your dog, the history you provide, a skin biopsy, and immune testing. Other autoimmune or ulcerative skin disorders must be ruled out.

How is ... treated?:

Mild cases can be treated with steroid creams or relatively low doses of glucocorticoids by mouth. More severe cases usually require a combination of medications, including high doses of glucocorticoids, to suppress the inappropriate immune response. These drugs usually must be given for prolonged periods, possibly for life. Your veterinarian will discuss with you potentially serious side effects of which you should be aware.

Because exposure to ultraviolet light can make the condition worse, it is wise to keep your dog out of direct sunlight from 10:00 to 3:00.

For the veterinarian:

Cases with severe, widespread lesions are clinically indistinguishable from pemphigus vulgaris. Intact vesicles or bullae are suggestive of bullous pemphigoid.

Breeding advice:

Although the inheritance of this condition is unknown, it is preferable not to breed affected dogs.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Immunologic Skin Diseases. In Muller and Kirk's Small Animal Dermatology. pp. 500-518. W.B. Saunders Co., Toronto.

German shepherd pyoderma

roblib — Mon, 19 Apr 2010 18:03:28 +0000

What is ... ?:

Bacterial skin infection (pyoderma) is very common in dogs, and is usually easily treated with antibiotics. Infection is almost invariably caused by Staphylococcus intermedius, which does not produce any problems in people.

Chronic, recurring, or deep infections can also occur, generally due to an underlying cause, and these are more difficult to treat. In German shepherds, a deep pyoderma is seen (meaning the infection extends beyond and beneath superficial structures in the skin) which causes severe chronic draining lesions in the area of the lower back and hind legs. Sometimes an underlying cause can be identified.

How is ... inherited?:

The predisposition to this condition is thought to be autosomal recessive; however as with all pyodermas, there are frequently other factors involved.

What breeds are affected by ... ?:

German shepherd

What does ... mean to your dog & you?:

The condition most often develops in middle-aged, otherwise healthy dogs. You may first notice that your dog bites at the lower back region, indicating itchiness. Early lesions such as pustules, erosions and crusting may be hidden by the haircoat but gradually there will be hair loss, deeper ulcerations and draining sinuses. The areas affected (lower back, outer thighs) may be quite painful.

How is ... diagnosed?:

The condition is diagnosed based on the clinical signs, response to antibiotics, and recurring nature.

How is ... treated?:

Predisposing factors such as fleas, flea-bite hypersensitivity, food allergies, and hypothyroidism must be identified and treated. Appropriate antibiotics must be given for a sufficient length of time, which may be as long as 6 to 10 weeks. Your veterinarian will likely also recommend antibacterial shampoos to remove infectious debris (discharge, crusts, etc).

This recurrent condition usually requires life-long management. Your veterinarian will work with you to devise a control programme that works for your dog, which may include immunomodulatory bacterins, long term antibiotic use, and/or regular antibacterial shampoos.

Breeding advice:

Avoid breeding affected dogs and their close relatives.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

DeBoer, D.J. 1995. Management of chronic and recurrent pyoderma in the dog. In J.D. Bonagura and R.W. Kirk (eds.) Kirk's Current Veterinary Therapy XII Small Animal Practice. p. 611-617. W.B. Saunders Co., Toronto.

Lupus erythematosus (systemic, cutaneous/discoid)

roblib — Mon, 19 Apr 2010 18:57:39 +0000

What is ... ?:

There are several forms of lupus erythematosus that are recognized in people, two of which have been identified in dogs. Lupus is an autoimmune disorder, meaning that the body mounts an inappropriate immune response to some part of itself.

Systemic lupus erythematosus (SLE) is an uncommon but severe disorder in which the inappropriate immune response is widespread in the body, and can cause arthritis, kidney disease, anemia, and skin disease. Cutaneous lupus erythematosus (CLE) is thought to be a milder variant of SLE, and the problems are confined to the skin. CLE is also called discoid lupus erythematosus

How is ... inherited?:

unknown, but the condition runs in families.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

SLE most commonly affects joints, muscle, skin, blood, and/or kidneys. The condition tends to wax and wane, so your dog will have periods of remission and of flare-up. The kinds of problems you may notice include shifting lameness (ie varies depending on which joint is affected at any time), weakness and pale gums (due to anemia), and/or increased drinking and urination (kidney disease). The face and the feet are the areas of the skin most often affected, with ulcers and loss of pigment on the nose, and ulceration and thickening of the footpads.

With CLE, you are most likely to see red, scaling areas of inflammation on your dog's face, and loss of pigment from the nose. There may also be lesions on the ears and thickening of the footpads. Affected dogs are otherwise healthy.
Nasal scarring is common with both SLE and CLE. Exposure to ultraviolet light is a factor (especially in CLE), and so the condition is seen more often and is more severe in the summer and in sunny parts of the world.

How is ... diagnosed?:

Because SLE can affect many different body systems, diagnosis is challenging. (In fact it is sometimes called, "the great imitator"). Once suspected, diagnosis is confirmed by specific blood tests and biopsy for examination by a veterinary pathologist.

CLE is diagnosed through examination of biopsy samples.

How is ... treated?:

Treatment for SLE generally requires relatively high doses of steroids in combination with chemotherapy. In general, dogs with joint, muscle, or skin disease seem to respond better to medication, and have longer periods of remission, than those with severe blood or kidney problems. Unfortunately, many dogs with SLE die or are euthanized within a year of diagnosis, either due to the disease itself, the inability to control it, and/or unacceptable drug reactions. In other dogs, the disease can be well-controlled with medication for several years.

CLE is treated with relatively lower doses of steroids plus vitamin E and fatty acid supplements. Treatment generally needs to be lifelong, and dogs usually do well on it.
Exposure to ultraviolet radiation worsens the skin lesions in both conditions, so sunscreen is adviseable and dogs should be sheltered from peak sunlight (approximately 10:00 to 3:00).
For the veterinarian: Treatment for SLE must be individualized for each dog, generally starting with large doses of systemic glucocorticoids, and going to other immunomodulating or chemotherapeutic drugs if necessary. There is a good discussion of treatments for both forms of lupus erythematosus in the reference below.

For the veterinarian:

The list of rule-outs with SLE is extensive, due to the varied and changeable cutaneous and systemic manifestations of this disorder. Diagnosis is based on signs of multisystem involvement (most commonly anemia, thrombocytopenia, glomerulonephritis, polyarthritis, nasal and footpad dermatitis, fever of undetermined origin), a positive antinuclear antibody test, and histopathologic and immunopathologic evaluation.

Diagnosis of CLE is by histopathologic and immunopathologic evaluation.

Breeding advice:

Although the mode of inheritance is not known for either cutaneous or systemic lupus erythematosus, these conditions run in families. Affected animals should not be bred and it is prudent to avoid breeding their close relatives as well.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Immunologic Skin Diseases. In Muller and Kirk's Small Animal Dermatology. p. 578-588. W.B. Saunders Co., Toronto.

Pemphigus

roblib — Tue, 20 Apr 2010 17:20:23 +0000

What is ... ?:

Pemphigus covers a group of uncommon disorders that occur in dogs. With these conditions, there is an abnormal immune response to normal components of the skin, resulting in separation of cells. This leads to blisters, pustules, and crusting erosions in the skin. There are some similarities to pemphigus in humans, but many significant differences as well.

Breed predispositions are recognized for 2 forms - pemphigus foliaceus and the milder pemphigus erythematosus. (There are no breed predispositions recognized for the other 2 forms - p. vulgaris and p. vegetans).

How is ... inherited?:

unknown

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

Pemphigus foliaceus and erythematosus develop around 4 years of age. P. erythematosus is thought to be a milder form of p. foliaceus. Both conditions begin with pustular, crusty lesions on the face and ears. However with p. foliaceus, the lesions spread to the feet, the groin and other areas; there may be itching and pain; and severely affected dogs may lose their appetite and become depressed.

Loss of pigment in the nose is common with both forms of pemphigus, and this results in photodermatitis - increased sensitivity to the sun's rays so that the condition is worse in sunny weather.

How is ... diagnosed?:

P. foliaceus is the most commonly seen form of pemphigus; however it is still uncommon. Your veterinarian will base the diagnosis on your history of how the condition developed, physical examination of your dog, and tests such as skin scrapings and smears, skin biopsy, and immune testing to rule out other causes of similar skin lesions such as a bacterial or fungal skin infection, mites, seborrhea, dermatomyositis, and lupus erythematosus.

How is ... treated?:

Treatment is based on suppressing the inappropriate immune response. For pemphigus foliaceus, steroids (as a cream, or orally as a tablet - prednisone) are used to accomplish this. Once the condition is under control, your veterinarian will reduce the dosage to every second day to avoid the side effects which can occur with these drugs. Long term treatment is generally necessary. Where prednisone is not effective (as is sometimes the case), your veterinarian will try other immunomodulating drugs or chrysotherapy (gold salts).

For dogs that have lost pigment in the nose, protection against the sun is important to prevent flare-ups of the condition. Keep your dog out of the sun between 10:00 and 3:00 and/or use suncreens on the nose with SPF of 15 or higher.
The milder form, pemphigus erythematosus, may be successfully treated with sun avoidance and glucocorticoids applied to the skin. If this is ineffective, oral glucocorticoids or other drugs may be required.
For the veterinarian: A combination of tetracycline and niacinamide has been used with some success in dogs with p. erythematosus (Scott, 1995 below).

For the veterinarian:

Multiple skin biopsies will increase the chances of finding diagnostic histologic changes. Direct immunofluorescence or immunohistochemical testing may or may not be helpful. These tests have relatively low sensitivity and specificity.

Breeding advice:

It is advisable not to use affected dogs in breeding programmes, even though inheritance for these conditions has not been worked out.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Immunologic Skin Diseases. In Muller and Kirk's Small Animal Dermatology. p. 500-518. W.B. Saunders Co., Toronto.

Renal cystadenocarcinoma and nodular dermatofibrosis

roblib — Sun, 02 May 2010 02:49:14 +0000

What is ... ?:

This is a condition in German shepherd dogs in which lumps (nodules) form on the skin, generally on the head and legs. In most affected dogs, the condition is associated with cancer of the kidneys (renal cystadenocarcinoma), or of the uterus in females that have not been spayed.

How is ... inherited?:

The mode of inheritance is autosomal dominant with complete penetrance.

What breeds are affected by ... ?:

German shepherd

What does ... mean to your dog & you?:

Skin lesions are generally first seen in dogs over 5 years of age. You will notice small, firm, usually painless bumps or nodules on your dog's limbs and/or head. Over time these will increase in size and number. The lesions themselves cause few problems, although they may become ulcerated and painful as they grow larger. Most important however, is the fact that they are usually associated with cancer of the kidneys (or of the uterus in unspayed females). The signs that you may see if your dog has kidney disease include increased drinking and urination, loss of appetite and weight loss, a swollen abdomen (due to fluid retention or tumour size), depression, and vomiting.

How is ... diagnosed?:

Your veterinarian will surgically remove one of the skin nodules (a simple procedure done with local anesthetic) for examination by a veterinary pathologist. The biopsy will show changes characteristic of this condition. Your veterinarian will also look for signs of kidney disease. S/he may be able to feel that the kidneys are enlarged or you may have already noticed some of the typical clinical signs listed above. Your veterinarian will also take blood and urine samples to look for indications of kidney disease, and likely also recommend radiography or an ultrasound.

How is ... treated?:

There is no specific treatment for this condition. The nodules can be surgically removed if they are large or painful, and generally do not grow back if excised fully (although new ones will continue to appear). Unspayed females should be spayed, to remove the potential of cancer in the uterus and also because these dogs definitely should not be bred. Your veterinarian will carefully monitor your dog's kidney function - both kidneys are usually affected. Your veterinarian will discuss with you supportive care for your dog as kidney disease progresses, such as a special diet and fluid therapy when needed.

Breeding advice:

Affected animals should not be bred, and siblings and parents should be carefully examined for nodules. Because nodular dermatofibrosis has an autosomal dominant mode of inheritance, all dogs with the defective gene will develop the condition. Theoretically it should be possible to eradicate this problem. However because signs do not appear until the dogs are over 5 years of age, it is quite possible that they have already been used for breeding. The best course is to discontinue breeding lines in which there are affected dogs. Although there are no screening tests, computed tomography (a radiographic technique) is the best way to detect early cases.

FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Moe L, Lium B. Hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis in 51 German shepherd dogs. Journal of Small Animal Practice. 1997 38:498-505.

Pressler B. Cancer and the kidney. In: Bonagura JD, Twedt DC, eds. Kirk's Current Veterinary Therapy XIV. Missouri: Saunders Elsevier, 2009:928.

Sargan DR. Renal cystadenocarcinoma and.... In IDID - Inherited diseases in dogs:web-based information for canine inherited disease genetics.

acanthosis nigricans

roblib — Mon, 03 May 2010 17:02:30 +0000

What is ... ?:

This is a disorder of hyperpigmentation (an increase of the dark pigment melanin) in the skin. This condition can occur in any breed secondary to other skin disorders, but the inherited primary form is seen almost exclusively in the dachshund.

How is ... inherited?:

The mode of inheritance has not been established, although autosomal recessive or polygenic inheritance has been proposed.

What breeds are affected by ... ?:

Dachshund

What does ... mean to your dog & you?:

The disorder first appears at 3 to 12 months of age. It starts in the underarm region as darkening of the skin, which gradually becomes thickened, leathery, and hairless. Often the groin region is affected, and sometimes the condition spreads to other parts of the body as well.
Commonly there is seborrhea (the skin becomes greasy with a rancid odour) and this sets up a favorable environment for a yeast or bacterial infection to develop. These conditions usually cause itchiness, and your dog's scratching can cause trauma to the skin and a worsening of the problem.

How is ... diagnosed?:

Diagnosis is based on the typical appearance of this condition in a young dachshund.

How is ... treated?:

Primary acanthosis nigricans can not be cured, but it can be successfully managed. Your veterinarian will advise you on ways to achieve this, through such measures as regular bathing with anti-seborrheic shampoos, and through appropriate treatment of any secondary conditions that develop.
For the veterinarian: Topical therapy, oral vitamin E, corticosteroids, and injectable melatonin have all been used with some success.

For the veterinarian:

Malassezia dermatitis and staphylococcal pyoderma are common secondary invaders with acanthosis nigricans.

Breeding advice:

Preferably, affected dachshunds should not be used for breeding.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Muller and Kirk's Small Animal Dermatology. pp. 782-4. W.B. Saunders Co., Toronto.

acral lick dermatitis (lick granuloma)

roblib — Mon, 03 May 2010 17:04:45 +0000

What is ... ?:

This is a complex disorder in which dogs lick continuously at an area on their leg , which becomes raw, weeping, and ulcerated. The cause is unknown but inheritance may play a role, since certain breeds are affected more commonly. Boredom or frustration are considered contributing factors. Other possibilities include a disorder of the sensory nerves, or an obsessive-compulsive disorder.

How is ... inherited?:

No mode of inheritance has been established.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

Owners are generally amazed by the amount of damage a dog can do to his/her limb simply by continuous licking. Frequently the affected area becomes secondarily infected (pyoderma).
Boredom and frustration are thought to play a role in this condition, which is often seen in highly intelligent dogs who spend much of their day alone.

How is ... diagnosed?:

It is important to rule out any underlying cause of the condition. Your veterinarian will likely do a skin biopsy for this purpose. This is a simple procedure, done with local anesthetic, in which your veterinarian removes a small sample of your dog's skin for examination by a veterinary pathologist.

How is ... treated?:

Lick granulomas can be difficult for veterinarians to treat, and frustrating for the owner. Because boredom and frustration are thought to play a role in this condition, your veterinarian will likely discuss with you environmental enrichment and behaviour modification for your dog. S/he may prescribe certain drugs with anti-depressant or anti-anxiety properties for short periods, relying on your help in assessing the effects. Topical corticosteroids may help as well.
As the area is frequently secondarily affected, anti-bacterial therapy may be necessary.

For the veterinarian:

Rule-outs include neoplasia, pressure point granulomas,various infectious agents, underlying sensitivities, allergies, histiocytomas, mastocytomas.

Breeding advice:

Because inheritance appears to play a role in this complex condition, it is preferable not to breed dogs in whom acral lick dermatitis is a problem.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

acral mutilation syndrome

roblib — Mon, 03 May 2010 17:08:02 +0000

What is ... ?:

This is a bizarre syndrome in which dogs lose pain sensation in their toes. This is due to abnormal development and slowly progressive degeneration after birth of the sensory neurons in the spinal cord and in peripheral nerves.
Affected dogs initially chew at their feet but eventually will do extensive damage.

How is ... inherited?:

This condition is believed to be autosomal recessive.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

Affected pups usually begin to bite and lick their feet at 3 to 5 months of age, and have no temperature or pain sensation in the toes and sometimes up the legs. The hind legs are most severely affected.
Your dog's toes and feet will become swollen and ulcerated. S/he will continue to walk without any apparent discomfort on the mutilated feet.
Unfortunately attempts to prevent further mutilation are generally unsuccessful.

How is ... diagnosed?:

The diagnosis can usually be made based on distinctive clinical signs in a young dog of a typical breed. More than one pup in a litter may be affected. Electromyography will give a definitive diagnosis by revealing an absence of normal nerve potentials in your dog.
Diagnosis can also be made at necropsy, based on the characteristic changes in the nervous system.

How is ... treated?:

Unfortunately there is no treatment. Attempts to prevent mutilation through the use of bandages, collars or sedation are unsuccessful and, as the mutilation worsens, owners generally request euthanasia.

For the veterinarian:

These dogs have paronychia and may have autoamputation of the toes. Proprioception is normal, other reflexes are intact. EMG shows no denervation potentials.

Breeding advice:

There is no test for carriers of this disorder. Parents and siblings of affected dogs should not be used for breeding.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Muller and Kirk's Small Animal Dermatology. p 799. W.B. Saunders Co., Toronto.

canine acne

roblib — Mon, 03 May 2010 17:22:54 +0000

What is ... ?:

Dogs with canine acne develop multiple comedones on their chin, lips, and muzzle. These plugs of keratin and sebum block the hair follicles, and are commonly called "blackheads."

How is ... inherited?:

The mode of inheritance is unknown.

What does ... mean to your dog & you?:

Animals with this syndrome have bumps, scabs and blackheads on their lips, chin and muzzle. These usually do not bother the dog unless a secondary bacterial skin infection develops. This can cause pain and itching and your dog may paw at his/her face or rub it along the carpet.
The dog's general health is not affected by canine acne.

How is ... diagnosed?:

The diagnosis is made based on finding comedones or blackheads. Your veterinarian may take a skin biopsy to confirm the diagnosis. This is a simple procedure done with local anesthetic, in which your veterinarian removes a small sample of your dog's skin for examination by a veterinary pathologist.

How is ... treated?:

This condition can not be cured but it can be controlled. Mild cases need no treatment. In other cases or where there are repeated infections, regular cleaning with acne cleaning products or mild anti-seborrheic shampoos will be required. Your veterinarian will work with you to find a regime suitable for your dog.
If a secondary bacterial infection develops, your dog will need to take antibiotics for 3 or 4 weeks.
For the veterinarian: Refractory cases may respond to retinoid therapy.

Breeding advice:

It is preferable not to breed affected dogs.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Campbell, K.L. 1997. Diagnosis and management of keratinization disorders in dogs. ACVIM- Proceedings of the 15th Annual Veterinary Medical Forum. p 220-222.

colour dilution alopecia

roblib — Mon, 03 May 2010 18:35:31 +0000

What is ... ?:

This condition develops in some, but not all dogs that have been bred for unusual coat colour, especially "fawn" (a dilution of a normally red or brown coat) or "blue" ( a dilution of the normal black and tan coat colour). Alopecia means hairlessness - affected dogs have a poor, patchy haircoat progressing to widespread permanent hair loss. At the cellular level, there are abnormalities of the hair follicles and uneven clumping of pigment (melanin) granules in the hair shafts in affected areas

How is ... inherited?:

The inheritance is unclear. The condition is thought to be due to the interaction of different factors at the gene position for colour. It is not simply determined by the genes at that locus, because not all dogs with colour dilution develop coat problems.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

Dogs with this condition are born with a normal haircoat. Those with lighter blue or fawn hair coats usually start to show changes by 6 months while in dogs with darker steel blue coats, the changes may not be evident until 2 or 3 years of age. Your dog will experience hair loss and dry skin. Sometimes the earliest sign is a recurring bacterial infection (folliculitis), generally on the back, where you will see small bumps which are infected hair follicles. This clears up temporarily with antibiotics, but the affected area is very slow to regrow hair, or remains hairless.
Hair loss is usually first apparent on the back and by 2 or 3 years has spread over all the light coloured areas of the body. The exposed skin is often scaly and is susceptible to sunburn or extreme cold. Your dog's health is not otherwise affected by this condition.

How is ... diagnosed?:

Your veterinarian may suspect this disorder if your dog has typical haircoat changes and is an unusual colour for the breed. The diagnosis is confirmed through microscopic examination of plucked hairs or a skin biopsy. The latter is a simple procedure, done with local anesthetic, in which your veterinarian removes a small sample of your dog's skin for examination by a veterinary pathologist. The biopsy will show changes characteristic of this condition.

How is ... treated?:

Your dog can lead a normal healthy life with periodic symptomatic treatment as needed - moisturizing rinses for dry scaly skin or antibiotics for bacterial infections.
Since early hair loss occurs due to breakage, you may be able to slow the rate of loss by avoiding harsh shampoos and vigorous grooming.
For the veterinarian: There have been some early reports of hair regrowth using etretinate treatment . (See resource below.)

For the veterinarian:

Careful microscopic examination of plucked hairs will show large clumps of melanin distributed unevenly along the hair shaft.
In young dogs, demodicosis or other inherited hair defects should be considered while in dogs with a later onset (2 to 3 years of age), endocrine disorders (particularly hypothyroidism) should be ruled out.

Breeding advice:

Affected dogs, their parents and siblings should not be used for breeding. The condition can be entirely avoided by the use of non-colour-diluted dogs in breeding programmes.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Muller and Kirk's Small Animal Dermatology. p. 777. W.B. Saunders Co., Toronto.

Power, H.T., Ihrke, P.J. 1995. The use of synthetic retinoids in veterinary medicine. In S.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary Internal Medicine. p 585-590. W.B. Saunders Co., Toronto

congenital hypotrichosis

roblib — Mon, 03 May 2010 18:38:16 +0000

What is ... ?:

Dogs with this condition have hair loss at birth or by a few months of age, due to faulty development or a complete absence of some or all of the hair follicles from which the hairs normally grow. In some dogs other structures such as the sweat glands or the teeth are affected as well. The hair loss is not linked to coat colour as with colour dilution alopecia.
See also ectodermal defect.

How is ... inherited?:

The mode of inheritance has not been established and probably varies, as does the condition itself, between breeds. Most cases have been seen in male dogs, suggesting a sex-linked inheritance. Some breeds have been intentionally bred to produce hairlessness, including the Mexican hairless dog and the Chinese crested dog.

What breeds are affected by ... ?:

What does ... mean to your dog & you?:

The hairless (or alopecic) areas are commonly the head, ears and abdomen. Where hair loss is more general, there is usually only minimal hair remaining on the very top of the head, and at the end of the tail and legs. This is similar to the pattern of hair growth in dogs that are bred to be hairless.
This condition does not affect your dog's general health. Over time, the skin often becomes darkened and seborrheic (greasy, scaly and malodorous). Dogs with pale skin will be more susceptible to environmental damage, particularly frostbite or sunburn.

How is ... diagnosed?:

Congenital hypotrichosis is suspected when a dog has areas of hair loss (that do not worsen) from birth or shortly thereafter. The diagnosis is confirmed through a skin biopsy, a simple procedure done with local anesthetic in which your veterinarian removes a small sample of your dog's skin for examination by a veterinary pathologist. The biopsy will show the absence or severe underdevelopment of hair follicles characteristic of this condition.

How is ... treated?:

The hair loss is permanent. If seborrhea develops it can be managed with anti-seborrheic shampoos.

Breeding advice:

Do not breed affected dogs or their parents. Where the condition appears to be sex-linked (occurring only in males), the mothers are carriers of the trait and should not be used for breeding.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Resources:

Scott, D.W., Miller, W.H., Griffin, C.E. 1995. Muller and Kirk's Small Animal Dermatology. p. 771. W.B. Saunders Co., Toronto.