Alopecia X is a type of adult-onset follicular dysplasia in dogs previously known by many other names. The condition was first described in 1977. The condition is believed to be caused by a genetic predisposition to a hormone defect. Often dogs will recover after neutering. [1] [2]
The condition was previously known under multiple names including: adult-onset growth hormone deficiency, growth hormone responsive alopecia, castration responsive alopecia, biopsy responsive alopecia, black skin disease, and congenital adrenal hyperplasia-like syndrome. Today it is known as Alopecia X which reflects the unknown origin of the disease. [3]
The cause is not unknown. [2] [3] One theory of a growth hormone deficiency being the cause was abandoned when multiple studies showed normal growth hormone responses following stimulation and normal IGF-1 levels in affected dogs. Why some dogs with alopecia X show a suppressed growth hormone response remains unknown. [3] Mild hypercortisolism has been suggested as a cause of alopecia X in miniature Poodles and Pomeranians. [3]
Alopecia X primarily affects breeds with long and dense coats such as the Pomeranian, Keeshond, Chow Chow, Siberian Husky, and Alaskan Malamute. [4]
Initial signs of alopecia X are hair loss around the collar and rear thighs that slowly progresses to near complete alopecia of the trunk, neck, and proximal legs. The head, distal legs, and distal tail do not experience alopecia. In some cases a sparse wooly coat will remain. Hyperpigmentation develops simultaneously; however it may not occur, especially in white-coated Poodles. Aside from this clinical affects are not notable. [3]
Diagnosis is done via the exclusion of endocrinopathies, including: hypercortisolism, hypothyroidism, hyperoestrogenism, and hyperprogesteronism (a rare condition in some adrenocortical or testicular tumours), as well as other conditions such as, cyclic flank alopecia, follicular dysplasia, and sebaceous adentitis. A skin biopsy will typically show the same changes as other endocrinopathies. There is no way to consistently and reliably differentiate alopecia X from other conditions. However 'flame follicles' — which are spikes of fused keratin that seem to protrude through the outer root sheath to the vitreous layer that creates a type of 'fiery' effect — appear to be more common in alopecia x than other dermatopathies. [3]
Various treatments have been used to treat alopecia X, such as: growth hormones, castration, melatonin, mitotane, and trilostane. Treatment is not always effective, and because hair cycle arrest is a 'cosmetic' disease the risk of treatment needs to be compared to the benefit. [3] Growth hormone treatment can cause iatrogenic diabetes mellitus so other treatments have been investigated. Anecdotal and experimental results have been promising for melatonin, mitotane, and parenteral medroxyprogesterone acetate. [4]
The Chow Chow is a spitz-type of dog breed originally from Northern China. The Chow Chow is a sturdily built dog, square in profile, with a broad skull and small, triangular, erect ears with rounded tips. The breed is known for a very dense double coat that is either smooth or rough. The fur is particularly thick in the neck area, giving it a distinctive ruff or mane appearance. The coat may be shaded/self-red, black, blue, cinnamon/fawn, or cream.
A labradoodle is a crossbreed dog created by crossing a Labrador Retriever and a Standard or Miniature Poodle. Labradoodles were intended to be a good choice for people with allergies to canine dander.
The Poodle, called the Pudel in German and the Caniche in French, is a breed of water dog. The breed is divided into four varieties based on size, the Standard Poodle, Medium Poodle, Miniature Poodle and Toy Poodle, although the Medium Poodle is not universally recognised. They have a distinctive thick, curly coat that comes in many colors and patterns, with only solid colors recognized by breed registries. Poodles are active and intelligent, and are particularly able to learn from humans. Poodles tend to live 10–18 years, with smaller varieties tending to live longer than larger ones.
Skin disorders are among the most common health problems in dogs, and have many causes. The condition of a dog's skin and coat is also an important indicator of its general health. Skin disorders of dogs vary from acute, self-limiting problems to chronic or long-lasting problems requiring life-time treatment. Skin disorders may be primary or secondary in nature, making diagnosis complicated.
The coat of the domestic dog refers to the hair that covers its body. Dogs demonstrate a wide range of coat colors, patterns, textures, and lengths.
The Dobermann is a German breed of medium-large working dog of pinscher type. It was originally bred in Thuringia in about 1890 by Louis Dobermann, a tax collector. It has a long muzzle and – ideally – an even and graceful gait. The ears were traditionally cropped and the tail docked, practices which are now illegal in many countries.
Mitotane, sold under the brand name Lysodren, is a steroidogenesis inhibitor and cytostatic antineoplastic medication which is used in the treatment of adrenocortical carcinoma and Cushing's syndrome. It is a derivative of the early insecticide DDT and an isomer of p,p'-DDDTooltip dichlorodiphenyldichloroethane (4,4'-dichlorodiphenyldichloroethane) and is also known as 2,4'-(dichlorodiphenyl)-2,2-dichloroethane (o,p'-DDD).
Elbow dysplasia is a condition involving multiple developmental abnormalities of the elbow-joint in the dog, specifically the growth of cartilage or the structures surrounding it. These abnormalities, known as 'primary lesions', give rise to osteoarthritic processes. Elbow dysplasia is a common condition of certain breeds of dogs.
Follicular dysplasia is a genetic disease of dogs causing alopecia, also called hair loss. It is caused by hair follicles 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.
Progressive retinal atrophy (PRA) is a group of genetic diseases seen in certain breeds of dogs and, more rarely, cats. Similar to retinitis pigmentosa in humans, it is characterized by the bilateral degeneration of the retina, causing progressive vision loss culminating in blindness. The condition in nearly all breeds is inherited as an autosomal recessive trait, with the exception of the Siberian Husky (inherited as an X chromosome linked trait) and the Bullmastiff (inherited as an autosomal dominant trait). There is no treatment.
Pattern hair loss is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front hairline, loss of hair on the crown and vertex of the scalp, or a combination of both. Female-pattern hair loss (FPHL) typically presents as a diffuse thinning of the hair across the entire scalp.
Trilostane, sold under the brand name Vetoryl among others, is a medication which has been used in the treatment of Cushing's syndrome, Conn's syndrome, and postmenopausal breast cancer in humans. It was withdrawn for use in humans in the United States in the 1990s but was subsequently approved for use in veterinary medicine in the 2000s to treat Cushing's syndrome in dogs. It is taken by mouth.
Hypoadrenocorticism in dogs, or, as it is known in people, Addison's disease, is an endocrine system disorder that occurs when the adrenal glands fail to produce enough hormones for normal function. The adrenal glands secrete glucocorticoids such as cortisol and mineralocorticoids such as aldosterone; when proper amounts of these are not produced, the metabolic and electrolyte balance is upset. Mineralocorticoids control the amount of potassium, sodium, and water in the body. Hypoadrenocorticism is fatal if left untreated.
Non scarring hair loss, also known as noncicatricial alopecia is the loss of hair without any scarring being present. There is typically little inflammation and irritation, but hair loss is significant. This is in contrast to scarring hair loss during which hair follicles are replaced with scar tissue as a result of inflammation. Hair loss may be spread throughout the scalp (diffuse) or at certain spots (focal). The loss may be sudden or gradual with accompanying stress.
Sebaceous adenitis in an uncommon skin disease found in some breeds of dog, and more rarely in cats, rabbits and horses. characterised by an inflammatory response against the dog's sebaceous glands, which can lead to the destruction of the gland. It was first described in veterinary literature in the 1980s.
Cushing's syndrome disease, also known as hyperadrenocorticism and spontaneous hypercortisolism, is a condition resulting from an endocrine disorder where too much adrenocorticotropic and cortisol hormones are produced, causing toxicity. It may arise in animals as well as in humans. Cushing's is an umbrella term for conditions caused by elevated cortisol and adrenocorticotropic hormone levels.
Naked foal syndrome (NFS) is a genetic disorder specific to the Akhal-Teke horse breed. A rare genodermatosis, it is characterized by almost complete hairlessness and mild ichthyosis. The condition is inherited as a monogenic autosomal recessive trait, and affected horses typically die between a few weeks and three years of age. The exact cause of death in NFS-affected horses is not clear.
Hypothyroidism is an endocrine disorder in which the thyroid gland fails to produce sufficient thyroid hormones. Hypothyroidism is one of the most common endocrinopathies in dogs. It is either acquired or congenital.