Animalia Life

The Breed History
In Ancient times, it has been reported that the African hairless dog was taken to China where further breeding reduced the emerging breed to a toy size. Others place hairless South American dogs as distant relatives. First breed records date to the late 1800s. The Chinese crested dogs were left at ports of call around the world when sailors, who used the dogs onboard to control vermin, traded them with local merchants. In Mexico, they may have contributed to the development of the Chihuahua. First AKC registry occurred in 1991.

Breeding for Function
Historically, they were ratters, mousers, and companion dogs.

Physical Characteristics
Height at Withers: 11-13" (28-33 cm)
Weight: 5-12 lb (2-5.5 kg)
Coat: Two coat types exist: Hairless and Powderpuff. Hairless have no body hair. It is present only on the extremities and the head hair is called the crest. From the metacarpals and going distally, and from the tarsus distally they have socks of hair. The tail has a plume of hair as well. In all dogs the hair is silky, but the Powderpuff has a double coat. Any color is accepted, as is any color combination. Powderpuff is a full-coated variety. Mixed haircoat litters are born to Powderpuff X hairless and hairless X hairless crosses. These two varieties are generally crossed because the hairless dogs are not as vigorous (breeding, integument, missing teeth). The hairless type is AD, and homozygotes are not viable, so hairless dogs are heterozygotes.
Longevity: 12-13 years.
Points of Conformation: A fine-boned toy dog with almost square proportions. Eyes are wide set and nose and eyes are colored to match the coat, and almond shaped. Erect ears are large, the skull is wedge shaped, the stop distinct, and the muzzle tapers. In the hairless variety, missing teeth are not faulted but in Powderpuff they are. The slightly arched neck provides for high head carriage. The topline is level though the croup slopes down slightly. The thorax is moderately shallow and there is a moderate abdominal tuck. The tapered tail reaches the tarsus at rest, and is slender with a curve at the tip. In action the tail is held high or even over the back. Dewclaws may be removed. The finely boned limbs are straight, the feet are elongated with a "hare" conformation. The gait is quick and agile, but smooth. Skin may have a mottled pigmentation.

Recognized Behavior Issues and Traits
Reported attributes of the breed include: Playful, good for city and apartment living, low grooming needs but high bathing needs, lively, affectionate, does not tolerate temperature extremes well, especially cold. These dogs are very prone to sunburn and papules. They are low shedders, have a low barking tendency, and need close human companionship.

Normal Physiologic Variations
Hairlessness is caused by a dominant gene that is lethal in utero in the homozygous state. This gene also produces variably expressed missing premolars in the heterozygous state. Because of the lethal homozygous state, breeding two heterozygous hairless dogs together produces a 2:1 ratio of hairless to (homozygous normal) powderpuff dogs. Breeding hairless to powderpuff dogs, produces a 1:1 ratio of hairless to powderpuff offspring. Chinese crested dogs are very sensitive to heat and cold. The skin is thin, and prone to lacerations and dryness. They sweat through their skin so they do not pant as much as other breeds.

Drug Sensitivities
None reported

Inherited Diseases
Incomplete Dentition: It is common to have variable expression of missing premolars with the autosomal dominant hairless phenotype.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. OFA reports 4.5% affected.
Primary Lens Luxation (PLL) and Secondary Glaucoma: An autosomal recessive gene causes primary lens luxation. Homozygous affected dogs usually develop lens luxation between 4-8 years of age. Rarely, heterozygous carriers can develop lens luxation, but at a later age. Lens luxation can lead to secondary glaucoma and blindness. A genetic mutation has been identified, and a genetic test is available. OFA testing shows 27% carrier, and 2% affected.
Progressive Retinal Atrophy (PRA): More than one form of PRA occurs in the breed. The autosomal recessive prcd form (age of onset between 3-8 years) occurs, and a genetic test exists but prcd-PRA does NOT appear to be the predominant PRA disease type. 0.56% of Chinese Crested Dogs CERF examined by veterinary ophthalmologists between 2000-2005 are identified as affected, and 1.55% as suspicious for PRA. CERF does not recommend breeding Chinese Crested Dogs affected with PRA.
Hip Dysplasia and Legg-Calve Perthes Disease: Polygenically inherited traits causing degenerative hip joint disease and arthritis. Too few Chinese Crested Dogs have been screened by OFA to determine an accurate frequency.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. Too few Chinese Crested Dogs have been screened by OFA to determine an accurate frequency.
Canine Multiple System Degeneration (CMSD): This rare, autosomal recessive disorder causes progressive cerebellar ataxia, with its onset between nine and sixteen weeks of age. Histopathology shows loss of Purkinje's cells, then bilateral symmetric degeneration of the olivary nuclei, followed by degeneration of the substantia nigra and caudate nucleus. Affected dogs do not survive beyond 5-6 months of age.

Disease Predispositions
Vitreous Degeneration: Liquefaction of the vitreous gel which may predispose to retinal detachment and blindness. Vitreous Degeneration is reported in 7.69% of Chinese crested dogs CERF-examined by veterinary ophthalmologists between 2000-2005.
Hypothyroidism: Inherited autoimmune thyroiditis. 7.4% positive for thyroid auto-antibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Sunburn: Chinese crested dogs are very sensitive to sunlight (ultraviolet radiation). Sun block should be used when exposed to direct sunlight.
Cataracts: Anterior and posterior cortex intermediate cataracts predominate in the breed, although nuclear and capsular cataracts also occur. Reported in 5.92% of Chinese Cresteds presented to veterinary teaching hospitals. Identified in 2.02% of Chinese Crested Dogs CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Chinese Crested Dogs with a cataract.
Persistent Pupillary Membranes: Strands of fetal remnant connecting; iris to iris, cornea, lens, or involving sheets of tissue. The later three forms can impair vision, and dogs affected with these forms should not be bred. Identified in 1.85% of Chinese Crested Dogs CERF examined by veterinary ophthalmologists between 2000-2005.
Comedomes (Blackheads): The skin of Chinese crested dogs are prone to spontaneous comedome formation throughout the dorsal skin, on the limbs and prepuce. Plugged follicles containing abundant sebum and keratic substances resembles human acne.
Deafness: Unilateral or bilateral congenital deafness is reported by Strain. Diagnosed by BAER testing.
Brachygnathism and Prognathism are reported.

Isolated Case Studies
None reported

Genetic Tests
Tests of Genotype: Direct test for prcd-PRA test is available from Optigen. Direct test for PLL is available from the OFA and the Animal Health Trust.
Tests of Phenotype: CHIC Certification: Required testing includes CERF eye examination (annually), patella evaluation (at a minimum of 1 year of age), and a congenital cardiac evaluation. Optional testing includes genetic tests for PLL and prcd-PRA, BAER hearing test, and hip radiographs. Recommend elbow radiographs and thyroid profile including autoantibodies.

Miscellaneous
- Breed name synonyms: Crested, Crestie, Powderpuff, Chinese Edible dog (historical), Chinese Hairless, Chinese Royal Hairless, Chinese Ship Dog (historical), South African Hairless (historical in Africa), Pyramid or Giza Hairless (historical name in Egypt)
- Registries: AKC, UKC, CKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club)
- AKC rank (year 2008): 54 (2,098 dogs registered)
- Internet resources: American Chinese Crested Club Inc.: www.accc.chinesecrestedclub.info/
Chinese Crested Club of Great Britain: www.thechinesecrestedclubofgb.co.uk
Chinese Crested Club of Canada: www.chinesecrestedclubcanada.com