Genetic Welfare Problems of Companion Animals

An information resource for prospective pet owners

Shar Pei

Shar Pei

Skin Fold Dermatitis

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

Outline: Shar Pei commonly get skin infections because of their thickened and folded skin, which causes recurring bouts of skin irritation and soreness.


Summary of Information

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1. Brief description

Shar Pei have a large volume of unusually thickened skin and thick, bristle-like hair. Folds are common on the trunks and legs of puppies and persist as folds on the heads of adults. 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 are common and contribute to the welfare concerns.

2. Intensity of welfare impact

There is a moderate-severe welfare problem. Common in puppies and in many adults, it does not directly lead to death but can cause lifelong irritation with episodes of pain.

3. Duration of welfare impact

More common in puppies, adult dogs are also frequently affected. Constant lower-grade skin irritation with episodes of infection and pain may be expected throughout the lives of affected adult dogs.

4. Number of animals affected

Published figures are not available but it is known that Shar Pei are predisposed to skin fold dermatitis as the presence of abnormally thick skin and bristle-like hairs are characteristic of the breed. An excessive volume of skin with wrinkles and folds is another common feature of many Shar Pei and reducing this has been the aim of recent changes to the UK Kennel Club’s breed standard. 

5. Diagnosis

Examination of the skin by a veterinary surgeon is usually adequate. Diagnostic tests to rule out significant concurrent diseases that require specific treatment are sometimes needed.

6. Genetics

This condition has a clear genetic basis as all Shar Pei have the skin characteristics that predispose to it. The disease appears to be a direct consequence of the skin characteristics selected for in the development of this breed. However, the specific genetics – the genes involved in this condition – have not been investigated.

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

Only by examination of the animal and its relatives and knowing whether any of these dogs have been previously treated for skin conditions.

8. Methods and prospects for elimination of the problem

This disease is associated with abnormal skin characteristics including the presence of skin folds. Breeding from dogs with these abnormal skin characteristics will perpetuate the problem, breeding from those with normal skin and with no history of skin fold dermatitis should help prevent the disease being perpetuated.


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1. Clinical and pathological effects

The Shar Pei is a breed known for its thick wrinkled skin. There are two reasons for this appearance. Partly this appearance is due to it having an excessive volume of skin. Also, Shar Pei have skin which is different in structure to the skin of other dogs. It has more of a substance called mucin (or hyaluronan) than other dogs which gives its skin increased thickness, contributing to the production of thicker skin folds (Zanna et al 2009, Akey et al 2010). 

Shar Pei have excessive skin all over their bodies, but particularly on the trunk and limbs when puppies (Nuttall et al 2009).This excessive or “redundant” skin forms into folds where skin surfaces rub together and may lead to skin irritation. It also creates pockets of moist warm skin, which favour the growth of bacteria and yeasts normally present on the surface of the skin in small numbers (Scott et al 1995). These bacteria and yeasts feed on the trapped skin secretions, multiply and produce substances that cause further irritation to the skin. Abnormal bacterial growth in the skin folds also often occurs leading to more severe infections. Local infections in skin folds may be called skin fold pyoderma. As well as causing irritation and pain – especially when the skin becomes ulcerated – there may also be an unpleasant smelling discharge (Scott et al 1995). Fluids such as tears, saliva and urine can catch in the folds adding to disease.

The characteristic hair type of Shar Pei contributes to the development of the disease. The Kennel Club breed description (2009) states that the Shar Pei has an “extremely harsh coat which is straight and standing off the body”. In a skin fold these bristle-like hairs directly irritate the facing skin.

Another contributing factor in the condition is the presence of concurrent ‘seborrhoea oleosa’ in many Shar Pei This name describes the condition in which excessive skin secretions are produced (Gross et al 1992). Shar Pei are predisposed to this (Griffin et al 1993). Where excessive secretions are combined with the presence of skin folds the environment for bacterial and yeast overgrowth and infection is enhanced and infections are more likely and more difficult to control.

Shar Pei are also predisposed to a number of other skin conditions that if occurring in conjunction to skin fold dermatitis may make it worse and lead to more severe skin disease. These include atopy (allergic skin disease), demodicosis (infestation with Demodex mites), folliculitis (inflammation of the hair follicles), food hypersensitivity (food allergy), hypothyroidism, idiopathic mucinosis and IgA deficiency (Scott et al 1995). Atopy, demodicosis, folliculitis, food hypersensitivity themselves produce pruritus (itchiness).

Skin fold dermatitis is seen most commonly in Shar Pei puppies as they tend to have more folds. Many dogs grow out of their folds in the trunk and legs but it is common for problems to remain in adult Shar Pei, particularly round the head and face (Scott et al 1995).

An unpleasant odour is often is often the first sign of the condition noticed by an owner as the sore skin is hidden from casual view. There may also be a purulent discharge leading to matting of the coat and the skin may appear red. Sometimes ulceration and raw areas are easily seen on the skin. The affected dog may well be itchy (pruritic) and scratching at the skin will damage it further. Long term (chronic) cases can lead to the skin becoming thickened which will further worsen the extent of the skin folds and darker in colour (hyperpigmented) – although hyperpigmentation, in itself, is not a welfare problem (Guaguere et al 2008).

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2. Intensity of welfare impact

This disease has a significant impact on the welfare of many Shar Pei because of the level of discomfort it causes, the duration of the condition and the high proportion of animals that are affected. For moderately affected dogs the disease is likely to cause recurring bouts of skin irritation and soreness. In more severely affected dogs it could mean constant discomfort due to skin ulceration and soreness which, if widespread around the body, could be debilitating enough to cause depression of the 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. The Shar Pei is also predisposed to a number of other skin diseases which if occurring in partnership to skin fold dermatitis increase the likelihood of individuals being severely affected.

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3. Duration of welfare impact

Despite it often being worse in puppies, the condition will persist throughout the life of many Shar Pei if their skin folds remain (Scott et al 1995, Nesbitt and Ackerman 1991). Long term medication to control the problem will often be necessary but preventing an affected animal from being constantly irritated may be impossible.

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4. Number of animals affected

Although dermatologists are in agreement that Shar Pei are predisposed to this condition (Scott et al 1995, Guaguere et al 2008) and that those with very wrinkled skin have a high likelihood of suffering the condition, we are not aware of published studies on the prevalence. Worries over how common this condition is, along with the breed’s predisposition to other skin and eye conditions, led to the UK Kennel Club updating its breed standard in October 2009 in an attempt to reduce the welfare problems arising from these diseases.

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5. Diagnosis

A diagnosis is made by a veterinary surgeon examining the dog and ruling out other causes of skin irritation and itchiness such as mange or fleas. It is important for the vet to know if more than one condition is occurring simultaneously.

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6. Genetics

Although the skin abnormalities that predispose to this disease have an obvious genetic basis, currently there is no clear understanding of which genes are involved (but see below) or how they act. The breed has long been known to be more likely to get the problem compared with other dogs (Scott et al 1995).

Ramsden et al (2000) identified a condition in a human child, with abnormally thickened skin, similar to that of Shar Pei. They found similarly increased levels of hyaluronan in the child and in the Shar Pei they studied. They concluded that a genetic defect was the cause and that this led to raised levels of hyaluronan, (also called mucin) in the skin, leading to skin thickening in the child and the appearance of “normal” Shar Pei.

Recently, a gene shown to cause wrinkled skin, at least in some Shar Pei, has been identified. It is called “HAS 2”. This gene is involved in making an enzyme that helps make mucin (or hyaluronan) (Akey et al 2010). The gene is different in wrinkled skin Shar Peis compared to smoother skin Shar Pei (Akey et al 2010). Despite there not yet being full understanding of the genes responsible, Shar Pei breeders and the Kennel Club now recognise that it is important to try to breed out the susceptibility to skin fold dermatitis.

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

In the UK Kennel Club breed description, updated in October 2009; it states “excessive skin on body when mature is highly undesirable”. It also adds that the forelegs should be free of wrinkles when the dog is mature and the hind legs should be free of “excess” wrinkling. When deciding on a puppy, selection is complicated by puppies having more wrinkles than they will when adults. Examining the mother and father of the puppy is therefore advised. It is also wise 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 has had previous skin problems of any kind. Additional skin problems of any kind in the Shar Pei can increase the likelihood of skin fold dermatitis occurring. If expect advice is needed photos of the puppy and parents could be shown to your veterinary surgeon.

Ideally, only animals free from skin conditions (that are considered to have a genetic component) should be bred from and this includes animals that had skin fold dermatitis as puppies or as adults.

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8. Methods and prospects for elimination of the problem

This disease is associated with abnormal skin characteristics including the presence of skin folds. Breeding from dogs with these abnormal skin characteristics will perpetuate the problem, breeding from those with normal skin and with no history of skin fold dermatitis should help prevent the disease being perpetuated. 

It is possible that, in the future, genetic testing will be available to help selectively choose Shar Pei for breeding so that their offspring have less wrinkled skin, but arguably, there is no need for a genetic test as the problem caused by the genes responsible – the skin abnormalities – are readily apparent.

In the meantime, the UK Kennel Club and responsible breeders are trying to decrease this problem and other conditions the breed is predisposed to, by the introduction of a new breed standard for Shar Pei. Currently, The Shar Pei Club of Great Britain’s mission statement recommends “that its’ members who breed, participate in the UK Kennel Club’s Accredited Breeders Scheme and to make use of any future health schemes and genetic tests which may become available in the future in order to eradicate known health problems.” http://www.thekennelclub.org.uk/item/173.

It is arguable that unless dogs can be bred to have no skin folds, no excess of mucin in their skin and, perhaps, without their stiff hair coat, that it will be impossible to eliminate skin fold dermatitis. Because of the extent of these features currently present in Shar Pei, this may only be achievable with radical change of the Shar Pei type and out-crossing may be required.

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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 and to Alex German BVSc PhD DipECVIM-ca CertSAM MRCVS for his comments on it.

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10. References

Books

Griffin CE, Kwotchka KW and Macdonald JM (1993) Current Veterinary Dermatology, Mosby Year Book, St Louis

Gross TL Ihrke P and Walder E (1992) Veterinary Dermatopathology. A macroscopic and microscopic evaluation of canine and feline skin disease

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

Nesbitt G and Ackerman L (Eds) (1991) Dermatology for the small animal practitioner, exotics, feline, canine. USA: Veterinary Learning Systems Co.Inc

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: W.B.Saunders Company

Journals:

Akey J, Ruhe A, Akey D, Wong A, Connelly C, Madeoy J, Nicholase T and Neff M (2010) Tracking footprints of artificial selection in the dog genome.  Proceedings of the National Academy of Sciences of the United States of America. [On-line]. Avaliable at http://www.pnas.org/content/early/2010/01/06/0909918107.abstract. Accessed on 6.7.10

Ramsden CA, Bankier A, Brown TJ, Cowen PSJ, Frost GI, McCallum DD, Studdert VP and Fraser JR (2000) A new disorder of hyaluronan metabolism associated with generalized folding and thickening of the skin. The Journal of Pediatrics. 136, (1), p62-68

Zanna G, Docampo M, Fondevila D, Bardagi M, Bassols A and Ferrer L (2009) Hereditary cutaneous mucinosis in shar pei dogs is associated with increased hyaluronan synthase-2 mRNA transcription by cultured dermal fibroblasts. Vet Dermatol. October 2009; 20,(5-6), p377-382

Websites

Kennel Club of Great Britain (Oct 2009) Shar Pei Breed Standard. [On-line] Available at http://www.thekennelclub.org.uk/item/173. Accessed 6.7.10

Shar Pei Club of Great Britain (year) Welcome page. [On-line] Available at  http://www.sharpei-clubofgb.co.uk/. Accessed 6.7.10

© UFAW 2011


Credit for main photo above:

http://depositphotos.com/2455939/stock-photo-puppy-shar-pei.html ©Depositphotos.com/cynoclub