Follicular dysplasia
Encyclopedia
Follicular dysplasia is a genetic
disease of dog
s causing alopecia
, or hair loss. It is caused by hair follicle
s that are misfunctioning due to structural abnormality. There are several types, some affecting only certain breeds. Diagnosis is achieved through a biopsy
, and treatment is rarely successful. Certain breeds such as the Mexican Hairless Dog
and Chinese Crested Dog
are bred specifically for alopecia.
In some breeds hair follicles in certain parts of the body become progressively miniaturized, analogous to what occurs in male pattern baldness in humans. It is most commonly seen in Dachshund
s, Miniature Pinscher
s, and Chihuahua
s. Affected areas become progressively more alopecic. The pattern of hairlessness that results is somewhat breed-dependent and sex dependent. In short-coated toy and miniature dogs, ventral neck, ventral chest, ventral abdomen and inner thighs are affected. In males, the pinnae (ear flaps) are affected. In Greyhound
s, the thighs are affected as well as the ventral chest and abdomen.
It causes bilateral hair loss and hyperpigmentation
of the flanks. The disease usually starts in the late fall or early spring, and can regrow in about six months, although the hair may be different in color or texture. Treatment with melatonin
may result in hair regrowth sooner, so it is thought that the amount of daylight influences this condition. The dogs are affected between the ages of two to four years.
. It usually occurs before the age of nine months and involves loss of some of the mahogany or red hair of the face and feet. It is caused by lipid
invasion of the hair follicle cells.
Color dilution alopecia is an inherited type of follicular dysplasia. It most commonly affects dogs with blue or fawn coats
, which are dilutions of black and brown, respectively. Dilution is caused by irregularities in melanin
transfer and storage. Melanosome
s may clump within melanocyte
s of the skin and hair follicles, causing the hair shafts to easily fracture. Signs of color dilution alopecia include hair loss and recurrent skin infection on the back. It can involve the whole body. The condition starts between the ages of six months and two years, depending on the degree of dilution. Early hair loss occurs due to hair breakage, making it similar to structural follicular alopecia. It is important to treat the skin infections, and etretinate
has been used to treat the hair loss.
and Alaskan Malamute
have a type of follicular dysplasia that occurs between the ages of three and four months, possibly later in the Malamute. The guard hair
s of the trunk are progressively lost and the coat turns reddish in color.
In black or red Dobermann
s, Miniature Pinscher
s, and Manchester Terrier
s there is a type of follicular dysplasia that occurs between the ages of one and four years. It begins in the flank and spreads to the back.
Black hair follicular dysplasia occurs in piebald
dogs and causes hair loss in black-haired areas soon after birth. It is most commonly seen in Papillon (dog)
, Gordon setter, Saluki and Bearded Collie
, and is known to occur in Large Münsterländer
dogs. It is considered to be similar to color dilution alopecia and is inherited as an autosomal recessive trait.
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
disease of dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s causing alopecia
Alopecia
Alopecia means loss of hair from the head or body. Alopecia can mean baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair can also produce hair loss. Hairstyling routines such as tight ponytails or braids may induce Traction alopecia. Both...
, or hair loss. It is caused by hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s that are misfunctioning due to structural abnormality. There are several types, some affecting only certain breeds. Diagnosis is achieved through a biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
, and treatment is rarely successful. Certain breeds such as the Mexican Hairless Dog
Mexican Hairless Dog
The Mexican Hairless Dog is a rare, hairless breed of dog, the size of which varies greatly. It is also known as Xoloitzcuintle .-History:...
and Chinese Crested Dog
Chinese Crested Dog
The Chinese crested dog is a smaller hairless breed of dog. Like most hairless dog breeds, the Chinese crested comes in two varieties, both with and without fur, which are born in the same litter: the Hairless and the Powderpuff....
are bred specifically for alopecia.
Structural follicular dysplasia
Structural follicular dysplasia varies by breed but all involve weakened hairs that break easily. Hair loss is originally seen in areas of repeated grooming or trauma, for instance the neck because of contact with a collar. Hair regrowth may occur, but the hair will be even weaker and the pattern will repeat. The dogs are affected between the ages of two to four years, and it is most commonly seen on the back towards the tail. Progression of the hair loss to cover the trunk can occur.Commonly affected breeds
- Irish Water SpanielIrish Water SpanielThe Irish Water Spaniel is a breed of dog that is the largest and one of the oldest of spaniels.The Irish Water Spaniel is considered one of the rarer breeds with the AKC in terms of registrations but is still widely respected and sought-after for its unusual qualities.-Appearance:The Irish Water...
- Portuguese Water DogPortuguese Water DogThe Portuguese Water Dog is a breed of working dog as classified by the American Kennel Club. Portuguese Water Dogs are originally from the Portuguese region of the Algarve, from where the breed expanded to all around Portugal's coast, where they were taught to herd fish into fishermen's nets, to...
- Curly Coated RetrieverCurly Coated RetrieverThe Curly Coated Retriever is a breed of dog originally bred in England for upland bird and waterfowl hunting. It is the tallest of the retrievers and is easily distinguishable by the mass of tight curls covering its body...
Atrophic follicular dysplasia / Pattern baldness
Dachshund
The dachshund is a short-legged, long-bodied dog breed belonging to the hound family. The standard size dachshund was bred to scent, chase, and flush out badgers and other burrow-dwelling animals, while the miniature dachshund was developed to hunt smaller prey such as rabbits...
s, Miniature Pinscher
Miniature Pinscher
The Miniature Pinscher is a small breed of dog, originating from Germany. The breed's earliest ancestors were a mix of Italian Greyhounds and Dachshunds...
s, and Chihuahua
Chihuahua (dog)
The ' is the smallest breed of dog and is so named for the state of Chihuahua in Mexico. Chihuahuas come in a wide variety of sizes, head shapes, colors and coat lengths.-History:...
s. Affected areas become progressively more alopecic. The pattern of hairlessness that results is somewhat breed-dependent and sex dependent. In short-coated toy and miniature dogs, ventral neck, ventral chest, ventral abdomen and inner thighs are affected. In males, the pinnae (ear flaps) are affected. In Greyhound
Greyhound
The Greyhound is a breed of sighthound that has been primarily bred for coursing game and racing, and the breed has also recently seen a resurgence in its popularity as a pedigree show dog and family pet. It is a gentle and intelligent breed...
s, the thighs are affected as well as the ventral chest and abdomen.
Cyclic follicular dysplasia
Cyclic follicular dysplasia is also known as seasonal alopecia.Hyperpigmentation
In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.-Causes:Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris...
of the flanks. The disease usually starts in the late fall or early spring, and can regrow in about six months, although the hair may be different in color or texture. Treatment with melatonin
Melatonin
Melatonin , also known chemically as N-acetyl-5-methoxytryptamine, is a naturally occurring compound found in animals, plants, and microbes...
may result in hair regrowth sooner, so it is thought that the amount of daylight influences this condition. The dogs are affected between the ages of two to four years.
Commonly affected breeds
- Silver Labrador
- Airedale TerrierAiredale TerrierThe Airedale Terrier is a breed of the terrier type that originated in Airedale, a geographic area in Yorkshire, England. It is traditionally called the "King of Terriers" because it is the largest of the terrier breeds...
- BulldogBulldogBulldog is the name for a breed of dog commonly referred to as the English Bulldog. Other Bulldog breeds include the American Bulldog, Olde English Bulldogge and the French Bulldog. The Bulldog is a muscular heavy dog with a wrinkled face and a distinctive pushed-in nose...
- Staffordshire TerrierStaffordshire TerrierStaffordshire Terrier may refer to:*Staffordshire Bull Terrier*American Staffordshire Terrier...
- Wirehaired Pointing GriffonWirehaired Pointing GriffonThe Wirehaired Pointing Griffon is a breed of dog used in hunting as a gundog. It is sometimes considered to be Dutch in ancestry, due to the breed founder, Eduard Korthals, nationality...
- BoxerBoxer (dog)Developed in Germany, the Boxer is a breed of stocky, medium-sized, short-haired dog. The coat is smooth and fawn or brindled, with or without white markings. Boxers are brachycephalic , and have a square muzzle, mandibular prognathism , very strong jaws and a powerful bite ideal for hanging on to...
- AffenpinscherAffenpinscher-History:The breed is German in origin and dates back to the seventeenth century. Its name is derived from the German Affe . The breed predates and is ancestral to the Griffon Bruxellois and Miniature Schnauzer....
Follicular lipidosis
Follicular lipidosis is a type of follicular dysplasia found in the RottweilerRottweiler
The Rottweiler is a medium to large size breed of domestic dog that originated in Rottweil, Germany. The dogs were known as "Rottweil butchers' dogs" because they were used to herd livestock and pull carts laden with butchered meat and other products to market...
. It usually occurs before the age of nine months and involves loss of some of the mahogany or red hair of the face and feet. It is caused by lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
invasion of the hair follicle cells.
Color dilution alopecia
Coat (dog)
The coat of the domestic dog refers to the hair that covers its body. A dog's coat may be a double coat, made up of a soft undercoat and a coarser topcoat, or a single coat, which lacks an undercoat...
, which are dilutions of black and brown, respectively. Dilution is caused by irregularities in melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
transfer and storage. Melanosome
Melanosome
In a biological cell, a melanosome is an organelle containing melanin, the most common light-absorbing pigment found in the animal kingdom.Cells that synthesize melanins are called melanocytes, and also the retinal pigment epithelium cells, whereas cells that have merely engulfed the melanosomes...
s may clump within melanocyte
Melanocyte
-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
s of the skin and hair follicles, causing the hair shafts to easily fracture. Signs of color dilution alopecia include hair loss and recurrent skin infection on the back. It can involve the whole body. The condition starts between the ages of six months and two years, depending on the degree of dilution. Early hair loss occurs due to hair breakage, making it similar to structural follicular alopecia. It is important to treat the skin infections, and etretinate
Etretinate
Etretinate is a medication developed by Hoffmann–La Roche that was approved by the FDA in 1986 to treat severe psoriasis...
has been used to treat the hair loss.
Commonly affected breeds
- DobermannDobermannThe Doberman Pinscher or simply Doberman, is a breed of domestic dog originally developed around 1890 by Karl Friedrich Louis Dobermann. Doberman Pinschers are among the most common of pet breeds, and the breed is well known as an intelligent, alert, and loyal companion dog...
- has the highest frequency of this condition. It occurs in 93 percent of blues and 75 percent of fawns. - Silver Labrador
- DachshundDachshundThe dachshund is a short-legged, long-bodied dog breed belonging to the hound family. The standard size dachshund was bred to scent, chase, and flush out badgers and other burrow-dwelling animals, while the miniature dachshund was developed to hunt smaller prey such as rabbits...
- Great DaneGreat DaneThe Great Dane , also known as German Mastiff or Danish Hound , is a breed of domestic dog known for its giant size...
- WhippetWhippetThe Whippet is a breed of dog in the sighthound family. They are active and playful and are physically similar to a small Greyhound.- Description :...
- Italian GreyhoundItalian GreyhoundThe Italian Greyhound is a small breed of dog of the sight hound type, sometimes called an "I.G.", or "Iggy" for short.-Appearance:The Italian Greyhound is the smallest of the sighthounds, typically weighing about and standing about tall at the withers...
- Chow ChowChow ChowChow chow is a breed of dog that was developed in China, where it is referred to as Songshi Quan , which literally means "puffy-lion dog".- Appearance :...
- Standard Poodle
- Miniature PinscherMiniature PinscherThe Miniature Pinscher is a small breed of dog, originating from Germany. The breed's earliest ancestors were a mix of Italian Greyhounds and Dachshunds...
- Yorkshire TerrierYorkshire TerrierThe Yorkshire Terrier is a small dog breed of terrier type, developed in the 19th century in the county of Yorkshire, England to catch rats in clothing mills. The defining features of the breed are its size, to , and its silky blue and tan coat...
- Silky Terrier
- ChihuahuaChihuahua (dog)The ' is the smallest breed of dog and is so named for the state of Chihuahua in Mexico. Chihuahuas come in a wide variety of sizes, head shapes, colors and coat lengths.-History:...
- Boston TerrierBoston TerrierThe Boston Terrier is a breed of dog originating in the United States of America. This "American Gentleman" was accepted in 1893 by the American Kennel Club as a non-sporting breed. Color and markings are important when distinguishing this breed to the AKC standard. They should be either black,...
- SalukiSalukiThe Saluki, also known as the Royal Dog of Egypt and Persian Greyhound is one of the oldest known breeds of domesticated dog. From the period of the Middle Kingdom onwards, Saluki-like animals appear on the ancient Egyptian tombs of 2134 BC. They have connections both to the Bible and Imperial...
- NewfoundlandNewfoundland (dog)The Newfoundland is a breed of large dog. Newfoundlands can be black, brown, gray, or black and white. They were originally bred and used as a working dog for fishermen in the Dominion of Newfoundland, now part of Canada. They are known for their giant size, tremendous strength, calm dispositions,...
- German Shepherd DogGerman Shepherd DogThe German Shepherd Dog , also known as an Alsatian or just the German Shepherd, is a breed of large-sized dog that originated in Germany. The German Shepherd is a relatively new breed of dog, with its origin dating to 1899. As part of the Herding Group, the German Shepherd is a working dog...
- Shetland SheepdogShetland SheepdogThe Shetland Sheepdog, often known as the Sheltie, is a breed of herding dog.They are small to medium dogs, and come in a variety of colors, such as sable/white, tri-color, and blue merle. They are vocal, excitable, energetic dogs who are always willing to please and work hard...
- SchipperkeSchipperkeA Schipperke is a small Belgian breed of dog that originated in the early 16th century. There has been a long informal debate over whether this type of dog is a spitz or miniature sheepdog.- Description :...
- Bernese Mountain DogBernese Mountain DogThe Bernese Mountain Dog, called in German the Berner Sennenhund, is a large breed of dog, one of the four breeds of Sennenhund-type dogs from the Swiss Alps. The name Sennenhund is derived from the German "Senne" and "hund" , as they accompanied the alpine herders and dairymen called Senn...
- BulldogBulldogBulldog is the name for a breed of dog commonly referred to as the English Bulldog. Other Bulldog breeds include the American Bulldog, Olde English Bulldogge and the French Bulldog. The Bulldog is a muscular heavy dog with a wrinkled face and a distinctive pushed-in nose...
Other types of follicular dysplasia
The Siberian HuskySiberian Husky
The Siberian Husky is a medium-size, dense-coat working dog breed that originated in north-eastern Siberia. The breed belongs to the Spitz genetic family...
and Alaskan Malamute
Alaskan Malamute
The Alaskan Malamute is a generally large breed of domestic dog originally bred for use as a utilitarian dog and later an Alaskan sled dog. They are sometimes mistaken for a Siberian Husky, but in fact are quite different in many ways...
have a type of follicular dysplasia that occurs between the ages of three and four months, possibly later in the Malamute. The guard hair
Guard hair
Guard hairs are the longest, coarsest hairs in a mammal's coat, forming the topcoat . They taper to a point and protect the undercoat from the elements. They are often water repellent and stick out above the rest of the coat...
s of the trunk are progressively lost and the coat turns reddish in color.
In black or red Dobermann
Dobermann
The Doberman Pinscher or simply Doberman, is a breed of domestic dog originally developed around 1890 by Karl Friedrich Louis Dobermann. Doberman Pinschers are among the most common of pet breeds, and the breed is well known as an intelligent, alert, and loyal companion dog...
s, Miniature Pinscher
Miniature Pinscher
The Miniature Pinscher is a small breed of dog, originating from Germany. The breed's earliest ancestors were a mix of Italian Greyhounds and Dachshunds...
s, and Manchester Terrier
Manchester Terrier
The Manchester Terrier is a breed of dog of the smooth-haired terrier type.-Appearance:Manchester Terriers are considered by most to be the oldest of all identifiable terrier breeds, finding mention in works dating from as early as the 16th century. In 1570 Dr...
s there is a type of follicular dysplasia that occurs between the ages of one and four years. It begins in the flank and spreads to the back.
Black hair follicular dysplasia occurs in piebald
Piebald
A piebald or pied animal is one that has a spotting pattern of large unpigmented, usually white, areas of hair, feathers, or scales and normally pigmented patches, generally black. The colour of the animal's skin underneath its coat is also pigmented under the dark patches and unpigmented under...
dogs and causes hair loss in black-haired areas soon after birth. It is most commonly seen in Papillon (dog)
Papillon (dog)
The papillon , also called the Continental Toy Spaniel, is a breed of dog of the Spaniel type. One of the oldest of the toy Spaniels, it derives its name from its characteristic butterfly-like look of the long and fringed hair on the ears. A papillon with dropped ears is called a phalène...
, Gordon setter, Saluki and Bearded Collie
Bearded Collie
The Bearded Collie, or Beardie, is a herding breed of dog once used primarily by Scottish shepherds, but now mostly a popular family companion....
, and is known to occur in Large Münsterländer
Large Munsterlander
The Large Munsterlander is a breed of gun dog originally from the Münster region in Germany.The Kennel Club in England recognised the breed in 1919 and established the breed standard in 1921.-Appearance:...
dogs. It is considered to be similar to color dilution alopecia and is inherited as an autosomal recessive trait.