Genetic welfare problems of companion animals

 

Skin Fold Dermatitis

 

Breed: Pekingese

 

Condition:  Skin Fold Dermatitis

Related terms: Intertrigo, localised pyoderma, skin fold pyoderma, frictional dermatitis

Outline: Pekinese commonly get skin infections because of their facial skin folds and wrinkles, which are prone to recurring bouts of skin irritation and soreness.

 


 

Summary of Information

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1.           Brief description

Pekingeses have a large amount of wrinkled skin on the head. This is because of the breed’s brachycephalic head confirmation (Nuttall et al 2009) and is the result of the discrepancy between the size of the much foreshortened muzzle and the skin which covers it. The skin is not proportionately reduced in size in relation to the muzzle (see also “Brachycephalic eye syndrome in Pekingese”).

 

Skin fold dermatitis occurs when the skin in these folds is irritated directly by hairs and skin rubbing together, combined with the accumulation of skin secretions. Skin infections commonly occur in these situations and contribute to the inflammation and irritation.

 

Pekingeses are also prone to disease in the skin folds around their abnormally shaped tails (Nuttall et al 2009).

 

 

2.           Intensity of welfare impact             

Skin fold dermatitis is a moderately severe welfare problem. It is common in puppies and in many adults. It can cause lifelong irritation with episodes of pain.

 

 

3.           Duration of welfare impact

Skin fold dermatitis is most common in puppies but adult dogs are also frequently affected. Constant low-grade skin irritation with more severe episodes of infection and pain may be expected throughout the lives of affected dogs.

 

 

4.           Number of animals affected

Although dermatologists are in agreement that Pekingeses are predisposed to this condition (Scott et al 1995, Guaguere et al 2008), and that those with more wrinkled skin have a high likelihood of suffering the condition, we are not aware of any data published on the prevalence of the condition in this breed.

 

5.           Diagnosis

The disease is diagnosed by examination of the affected skin. Diagnostic tests to rule out significant concurrent diseases that require specific treatment are sometimes needed.

 

6.           Genetics

The Pekingese has long been known to be predisposed to skin fold dermatitis compared with most other dog breeds (Scott et al 1995; Guaguere et al 2008).

 

The presence of facial skin folds is due to the brachycephalic head shape of Pekinese and this head shape is the result of an inherited defect (Stockard 1941). Recently the region of the canine genome associated with brachycephaly has been identified and two particular genes have been implicated but their identity is not known precisely (Bannasch et al 2010).

 

7.           How do you know if an animal is a carrier or likely to become affected?

Wrinkled skin and deep skin folds predispose affected animals to this condition. Any dog with skin folds because of a mismatch (as a result of selective breeding) between the size of the skin and the size of the underlying structures is at risk. Dogs with such skin are very likely to pass a predisposition to the disease on to their offspring.

 

8.          Methods and prospects for elimination of the problem

 

Breeding from dogs with excessive folds of skin will perpetuate the problem, but breeding from those with normal skin and with no history of skin fold dermatitis should help prevent the disease being perpetuated. However, skin folds are likely to be present in Pekingeses because of their abnormal, brachycephalic, head shape and their abnormal, curled, tails. Whilst these abnormalities remain part of the breed standard it may be hard to avoid skin folds and the diseases associated with them. The eradication of skin fold dermatitis may only be achievable by selecting for a normal head conformation and to achieve this, out-crossing may be required. Dogs that have shown any signs of skin fold dermatitis or that have had corrective surgery should not be used for breeding.

 

 


 

For further details about this condition, please click on the following:

 

 

 

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1.           Clinical and pathological effects

Pekingeses have large amounts of wrinkled skin on the head. This is due to the excessive size of skin compared to the structures that underlie it, eg the muzzle, etc. This discrepancy occurs because of the breed’s brachycephalic head confirmation (Nuttall et al 2009).

 

The brachycephalic head shape is due to an inherited defect in development of the bones of the skull (Stockard 1941). The head of the Pekinese is a normal width for the size of the animal but its length is markedly shorter. However, the soft tissues of the head do not show a similar and proportionate reduction in size and have to fit over the much reduced surface area of the skull. Externally this can be seen as wrinkles of the skin on the forehead and on the bridge of the nose (nasal folds).

 

These nasal folds also cause trichiasis – in which the hairs of the nasal skin fold come in constant direct contact with the surface of the eyes leading to eye irritation and damage (see “Brachycephalic eye syndrome in Pekingese”) (Gelatt and Peterson Gelatt 2001).

 

The disproportionately excessive or “redundant” skin forms into folds and the surfaces of this folded skin can rub together and lead to irritation. The folds also create pockets of inadequately ventilated, moist, warm skin, which favour the abnormal proliferation of the bacteria and yeasts that are normally present on the surface of the skin in small numbers (Scott et al 1995). These organisms feed on the skin secretions trapped in the fold and multiply and produce substances that cause further irritation to the skin. There may also be growth of bacteria of species that do not normally occur on the skin and some of these can cause more severe infections. Local infections in skin folds are sometimes called skin fold pyoderma. This causes irritation and pain and, especially when the skin becomes ulcerated, there can be an unpleasant smelling discharge (Scott et al 1995). Fluids such as tears, saliva and urine can catch in the folds adding to these problems.

 

An unpleasant odour is often the first sign of skin fold dermatitis that is noticed by an owner as the sore skin is hidden away from casual view in the fold. There may also be a discharge of pus, leading to matting of the coat and the skin may be inflamed and reddened. Sometimes ulcerated, raw areas of skin are readily apparent. Affected areas may be itchy (pruritic) and scratching may cause further damage to the skin. In chronic long term cases, the skin may become thickened, which may further worsen the extent of the skin folds, and it may darken in colour (Guaguere et al 2008).

 

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2.               Intensity of welfare impact

Skin fold dermatitis has a significant impact on the welfare of many Pekingeses because of the level of discomfort it causes, the duration of the disease, and the high proportion of animals that are affected. In moderately affected individuals, the disease is likely to cause recurring bouts of skin irritation and soreness. In those that are more severely affected, there may be constant discomfort due to skin ulceration and soreness and this may be debilitating enough to cause depression of the affected animal’s normal mental state and severe distress. Severely affected individuals may need constant or recurrent medicinal treatments to control the condition and surgery might be necessary in some cases to remove unwanted folds of skin.

 

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3.           Duration of welfare impact

The condition may persist throughout the life of many Pekingeses if their skin folds remain (Scott et al 1995). Long term medication to control the problem will often be necessary but even with treatment it may not be possible to prevent some degree of skin irritation.

 

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4.           Number of animals affected

 

Although dermatologists agree that Pekingeses are predisposed to this condition (Scott et al 1995, Guaguere et al 2008) and that those with more wrinkled skin have a high likelihood of suffering from the condition, we are not aware of any data on the exact number of Pekinese that suffer from it.


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5.           Diagnosis

Skin fold dermatitis is diagnosed by examining the skin and ruling out other causes of skin irritation and itchiness such as mange or fleas.

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6.           Genetics

Pekingeses have long been known to be predisposed to the disease compared with most other breeds of dog (Scott et al 1995, Guaguere et al 2008).

 

The facial skin folds are due to the brachycephalic head shape of Pekinese and this head shape is the result of an inherited defect (Stockard 1941). Recently, the region of the canine genome associated with brachycephaly has been identified and two particular genes have been implicated but their identity is not known precisely (Bannasch et al 2010).

 

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7.           How do you know if an animal is a carrier or likely to become affected?

Having nasal skin folds (wrinkles) is part of the Pekingese breed standard. The UK Kennel Club breed description, updated in October 2008; states, “A slight wrinkle, preferably broken, may extend from the cheeks to the bridge of the nose in a wide inverted ‘v’. This must never adversely affect or obscure eyes or nose” (Kennel Club 2011).

 

Finding a Pekingese with no skin folds on the head or around the tail therefore may be difficult. When choosing a puppy, examination of the mother and father of the puppy is advised. It is also sensible to ask the breeder if either has had any skin complaints in the past and not to buy a puppy where either it or one of its parents. Additional skin problems of any kind can increase the likelihood of skin fold dermatitis . If further, expert advice is needed in making a decision, photographs of the puppy and parents could be shown to your veterinary surgeon.

 

Ideally, only animals with normal, unwrinkled skin should be used for breeding.

 

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8.          Methods and prospects for elimination of the problem

Breeding from dogs with excessive folds of skin will perpetuate the problem, but breeding from those with normal skin and with no history of skin fold dermatitis should help prevent the disease being perpetuated. However, skin folds are likely to be present in Pekingeses because of their abnormal, brachycephalic, head shape and their abnormal, curled, tails. Whilst these abnormalities remain part of the breed standard it may be hard to avoid skin folds and the diseases associated with them. The eradication of skin fold dermatitis may only be achievable by selecting for a normal head conformation and to achieve this, out-crossing may be required. Dogs that have shown any signs of skin fold dermatitis or that have had corrective surgery should not be used for breeding.

 

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9.          Acknowledgements

UFAW is grateful to Rosie Godfrey BVetMed MRCVS and David Godfrey BVetMed FRCVS for their work in compiling this section.

 

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10.          References

Bannasch D, Young A, Myers J, Truvé K, Dickinson P et al (2010) Localization of Canine Brachycephaly Using an Across Breed Mapping Approach. PLoS ONE 5(3): e9632. doi:10.1371/journal.pone.0009632

 

Gelatt K and Peterson Gelatt J (2001) Small animal ophthalmic surgery: practical techniques for the veterinarian. Elsevier Science Ltd; Edinburgh

 

Guaguere E, Prelaud P and Craig M (2008) A practical guide to Canine Dermatology. Kalianxis: Italy

 

Kennel Club (2011) http://www.thekennelclub.org.uk/item/196 accessed 7.10.2011

 

Nuttall T, Harvey R and McKeever P (2009) A colour handbook of skin disease of the dog and cat. 2nd ED. London: Manson Publishing Ltd

 

Scott D, Miller W and Griffin C (1995) Muller and Kirk’s Small Animal Dermatology. 5th Ed. Philadelphia: WB Saunders Company

 

Stockard (1941) Wistar Institute Monograph. The genetic and endocrine basis for differences in form and behaviour as elucidated by studies of contrasted pure line dog breeds and their hybrids. Animal Anatomical Memoirs No 19, The Wistar Institute

 

© UFAW 2011

 

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