Animalia Life

The Breed History
The name means "lion" in Chinese. This dog perhaps originated in the Byzantine Empire or Tibet, though they are known to have reached China in the Tang Dynasty. Earliest records go back to about the year 625. Though they were brought to North America during World War II, they did not join AKC registry until 1969. It is possible the modern breed originated from Pekingese and Pug crossed with Tibetan dogs such as Lhasa Apso. Only 14 foundation dogs are thought to have been the source of the breed outside China since the 1900s.

Breeding for Function
They were bred for companionship and as a lapdog for the Chinese and Tibetan royalty.

Physical Characteristics
Height at Withers: female 9-10.5" (23-26.5 cm), male 9-10.5" (23-26.5 cm),
Weight: females 9-16 lb (4-7 kg), males 9-16 lb (4-7 kg).
Coat: Their dense, long, straight double coat can be any color. Longevity: 13-15 years.
Points of Conformation: In these toy dogs, the tail is carried over the back, head carriage is high and the topline is straight. Though a toy breed, the Shih Tzu is built with solid stature and they are longer than high. The large dark round eyes are not prominent, eyelid and lip margins are pigmented darkly. Skull is brachycephalic and the small muzzle is about one inch long. The nose is black except for the liver and blue dogs, where they are liver and blue to match. They have large pendulous ears, a definite stop and a prognathic jaw. The abdomen has no waist, and the chest consists of a deep moderately sprung ribcage. Dewclaws may be taken off, and the legs are straight. Their gait is powerful and straight.

Recognized Behavior Issues and Traits
These dogs are reported to be intelligent, very alert, and friendly. Their docile nature is a high priority in breeding programs because they are used solely as companion dog. They are alarm barkers. Their profuse coat should be groomed daily and may require a regular bath. Hair above the eyes is either trimmed or tied up. They are moderate shedders, and some owners prefer to have them clipped once to twice annually. They do well with children in the household. They enjoy close human contact, and have low to moderate exercise needs. They tolerate heat poorly.

Normal Physiologic Variations
None reported

Drug Sensitivities
None reported

Inherited Diseases
Renal Dysplasia: Autosomal dominant disease with incomplete penetrance causing renal failure. Affected dogs can succumb to renal failure from birth to two years of age. Mildly affected dogs can live with compensated renal insufficiency. Biopsy studies suggest that a majority of the breed is affected, although only a small percentage die from the condition. Dorn reports a 12.10x odds ratio for kidney disease in Shih Tzus versus other breeds. A direct genetic test for a susceptibility gene is available. (Affected dogs all have one copy of the gene, but most dogs with the gene will not develop kidney failure.)
Hip Dysplasia and Legg-Calve-Perthes Disease: Polygenically inherited traits causing degenerative hip joint disease and arthritis. OFA reports 19.4% affected.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. OFA reports 2.4% affected.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. Too few Shih Tzus have been screened by OFA to determine an accurate frequency.

Disease Predispositions
Distichiasis: Abnormally placed eyelashes that irritate the cornea and conjunctiva. Can cause secondary corneal ulceration. Identified in 15.59% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005. Dorn reports a 3.13x odds ratio in Shih Tzus versus other breeds.
Primary (Narrow Angle) Glaucoma: Ocular condition causing increased pressure within the eyeball, and secondary blindness due to damage to the retina. Can also predispose to lens luxation. Screen with gonioscopy and tonometry. Reported at a frequency of 16.5% in Japan. Diagnosed in 1.58% of Shih Tzus presented to veterinary teaching hospitals.
Brachycephalic Complex: The brachycephalic complex includes Stenotic Nares, Elongated Soft Palate, Everted Laryngeal Saccules, Laryngeal Collapse, and occasionally Hypoplastic Trachea. Can cause respiratory distress, apnea, and hypoxia. Early surgical correction of severe stenotic nares is recommended.
Epiphora: Ocular tear drainage with hair staining. Can occur secondary to medial canthal trichiasis and/or entropion. Shih Tzu are listed as the most frequently affected breed. Treat by keeping hair clipped short, and daily cleaning. Medial canthoplasty is curative in severe cases.
Entropion: Rolling in of eyelids, often causing corneal irritation or ulceration. Identified in 7.88% of Shih Tzus CERF examined by veterinary ophthalmologists between 2000-2005.
Vitreous Degeneration: Liquefaction of the vitreous gel which may predispose to retinal detachment. Identified in 7.36% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Cataracts: Juvenile and adult onset. Anterior or posterior intermediate cataracts predominate in the breed. Median age of 6.5 +/- 3.4 years. In one large study, 4.14% of Shih Tzus had cataracts. Identified in 5.43% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005. CERF Does not recommend breeding any Shih Tzu with a cataract.
Eury/Macroblepharon: An exceptionally large palpebral fissure. With laxity, may lead to lower lid ectropion and upper lid entropion. Either of these conditions may lead to severe ocular irritation. Identified in 3.50% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Exposure Keratopathy Syndrome/Pigmentary Keratitis: Corneal reactivity and drying from ocular exposure secondary to shallow orbits, exophthalmos, and lagophthalmos. Identified in 3.50% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Hypothyroidism: Inherited autoimmune thyroiditis. 3.0% positive for thyroid autoantibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Ectopic Cilia: Hair emerging through the eyelid conjunctiva. Ectopic cilia can cause discomfort and corneal disease. Identified in 1.93% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Corneal Dystrophy: Shih Tzus can have an epithelial/stromal form of corneal dystrophy. Identified in 1.75% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Umbilical Hernia: Inherited umbilical hernias occur at an increased frequency in Shih Tzus versus other breeds. Correct surgically if large.
Prolapsed Gland of the Nictitans (Cherry Eye): This condition occurs secondary to inflammation of the gland. Reported at an increased frequency in the breed.
Progressive Retinal Atrophy (PRA): Progressive degeneration of the retina leading to blindness. Mode of inheritance not defined. Reported in 1.23% of Shih Tzus CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Shih Tzu with PRA.
Chronic Superficial Keratitis (Pannus): Chronic corneal inflammatory process that can cause vision problems due to corneal pigmentation. Treatment with topical ocular lubricants and anti-inflammatory medication. Identified in 1.05% of Shih Tzus CERF-examined by veterinary ophthalmologists between 2000-2005.
Intervertebral Disc Disease (IVDD): Shih Tzus have an increased risk of developing spinal cord disease due to prolapsed disk material. Clinical signs include back pain, scuffing of paws, spinal ataxia, limb weakness, and paralysis. In a Japanese study, 11.4% of dogs with IVDD were Shih Tzus, primarily affecting the cervical spinal cord at an average age of 10 years.
Portosystemic Shunt (PSS, Liver Shunt): Can be intrahepatic, extrahepatic or microvascular dysplasia. Causes stunting, abnormal behavior, possible seizures, and secondary ammonium urate urinary calculi. Diagnose with paired fasted and feeding serum bile acid and/or ammonia levels, and abdominal ultrasound. 0.78% of Shih Tzus (odds ratio of 15.4x) presented to veterinary teaching hospitals had PSS.
Keratoconjunctivitis Sicca (KCS, Dry Eye): Ocular condition causing lack of tear production and secondary conjunctivitis, corneal ulcerations, and vision problems. In one study, 4.8% of dogs with KCS were Shih Tzus. Usually presents in the breed at 0-2 years of age, or 4-6 years of age. Treat with ocular lubricants and anti-inflammatory medications. CERF does not recommend breeding any Shih Tzu with KCS.
Urinary Calculi: The breed is found to be at an increased risk of developing struvite and oxalate calculi. Dorn reports a 2.74x odds ratio in Shih Tzus versus other breeds.
Optic Nerve Hypoplasia: Congenital malformation of the optic nerve causing blindness. 23% of reported cases are Shih Tzus. CERF does not recommend breeding any Shih Tzu with the condition.
Allergic Inhalant Dermatitis, Cleft Lip/Palate, Dermoid Sinus, Hydrocephalus, Malassezia Dermatitis, Oligodontia, Prognathism, Sebaceous Adenitis, Tricuspid Valve Dysplasia, and von Willebrand's Disease are reported.

Isolated Case Studies
Pancreatic Gastrinoma: Several cases of Shih Tzus with pancreatic gastinoma have been documented. Affected dogs present with vomiting, diarrhea and anorexia. Serum gastrin levels are elevated.28,29 Spinal Arachnoid Cyst: Two Shih Tzu littermates presenting with progressive ataxia and quadriparesis due to cranial cervical spinal arachnoid cysts. Treatment was surgical.
Atlantoaxial Subluxation: An eight month-old male Shih Tzu with symmetric ataxia, tetraparesis, and neck pain was diagnosed with atlantoaxial subluxation due to absence of the transverse ligament of the atlas and malformation of the dens and atlas. The pup was euthanized.
Polioencephalomyelopathy: A 17-month-old Shih Tzu presented with a 3 month history of progressive thoracic limb weakness consistent with a lesion affecting the cervicothoracic (C6 through T2) spinal cord. MRI identified symmetric lesions in the C5-C7 spinal cord, caudal colliculi, and vestibular and cerebellar nuclei. Pathology revealed polioencephalomyelopathy, similar to that seen in the mitochondrial disorder in Australian Cattle Dogs, and humans with Leigh disease.

Genetic Tests
Tests of Genotype: Direct test for a renal dysplasia susceptibility gene is available from Dogenes (dogenes.com). Direct test for coat color is available from VetGen. Tests of Phenotype: Recommended tests are; CERF eye examination, hip and elbow radiographs, patella examination, thyroid profile including autoantibodies, cardiac examination, and genetic test for renal dysplasia susceptibility.

Miscellaneous
- Breed name synonyms: Chrysanthemum-faced Dog, Shi Tzu, Lion dog
- Registries: AKC, CKC, UKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club)
- AKC rank (year 2008): 10 (20,219 dogs registered)
- Internet resources: American Shih Tzu Club: shihtzu.org
The Canadian Shih Tzu Club: canadianshihtzuclub.ca
Shih Tzu Club (UK): theshihtzuclub.co.uk