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 (glands found in the

hair follicles The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction betwe ...

in the skin dermis), which can lead to the destruction of the gland. It was first described in veterinary literature in the 1980s.

Signs

There are two expressions of this condition, one for long or double coated breeds and one for short coated breeds, both with differing presentations. * For long- or double-coated breeds such as Poodles, Akitas and Samoyeds, the condition often presents itself with silvery dandruff which adheres to the coat, hair loss (not to be confused with

moulting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

or "blowing coat"), a dull and brittle coat, and later on skin lesions along the back and ears as well as thickened skin and a musty or rancid odour. * For short-coated breeds such as Vizslas, the condition causes facial swellings, nodular skin lesions, fine dandruff which does not adhere to the coat, and a general "moth-eaten" appearance to the coat.

Cause

The signs of sebaceous adenitis are caused by an

inflammatory disease Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

process which affects the

sebaceous gland A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numb ...

s of the skin. The cause of the inflammatory disease is unknown. Different breeds of dogs may have different underlying causes of the disease. Research is currently underway to find if there is a genetic predisposition for sebaceous adenitis; the exact mode of inheritance remains unknown. In Standard Poodles, sebaceous adenitis is most likely an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and ...

inherited disease, with variable expression.

Diagnosis

In general, sebaceous adenitis is underdiagnosed in dogs. Diagnosis confirmation requires multiple punch biopsies analysed by a dermopathologist who will comment on the condition of the sebaceous glands, revealing granulomatous or pyogranulomatous inflammation surrounding the sebaceous glands or even complete destruction of sebaceous glands. Other conditions with similar presentations include: bacterial folliculitis and

demodicosis Demodicosis , also called Demodex folliculitis in humans and demodectic mange () or red mange in animals, is caused by a sensitivity to and overpopulation of '' Demodex spp.'' as the host's immune system is unable to keep the mites under control. ...

dermatophytosis Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple a ...

, endocrinopathy,

pemphigus foliaceus Pemphigus foliaceus is an autoimmune blistering disease ( bullous disorder) of the skin. Pemphigus foliaceus causes a characteristic inflammatory attack at the subcorneal layer of epidermis, which results in skin lesions that are scaly or crusted ...

, zinc responsive dermatosis, vitamin A-responsive dermatosis,

ichthyosis Ichthyosis is a family of genetic skin disorders characterized by dry, thickened, scaly skin. The more than 20 types of ichthyosis range in severity of symptoms, outward appearance, underlying genetic cause and mode of inheritance (e.g., dominan ...

, and nutritional deficiencies. As well as, superficial pyoderma, primary idiopathic seborrhea and other endocrine diseases.

Treatment

There is no cure for this condition. Treatment is generally lifelong and takes the form of bathing and soaking in mineral oils and washing with antibiotic shampoos to try to alleviate symptoms and slow the condition's progression. Antiseptic and antibiotic shampoos (chlorhexidine or benzoyl peroxide) are used to manage further secondary bacterial infection. For some breeds,

cyclosporine Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's diseas ...

corticosteroids Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are in ...

and

immunosuppressant Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system. Classification Immunosuppressive drugs can be classified into ...

drugs may be effective, and it is postulated, through some studies, that large doses of vitamin A given orally may result in some improvement. It has been suggested that the more aggressively one applies the

topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of class ...

methods of treatment, the less aggressively one needs to employ the immunosuppressant therapy. The suggestion is that this phenomenon may be due to a cyclic feedback whereby secondary infection, when not aggressively treated with topical therapy, increases and contributes to further sebaceous gland inflammation.

Topical therapy

This forms a major and critical part in the disease treatment and the shampoo treatment can need to be applied as often as 3 to 4 times per week. An antiseborrheic shampoo removes the scale blocking the follicles. The mineral oil soak, whereby the oil remains on the affected animal for at least 2 hours, is needed to replace epidermal lipids as well as to restore normal epidermal barrier function. The oil is then removed through the process of many baths. This oil treatment needs to be repeated at least once a week for 4 to 7 weeks until new hair growth is observed. Once new hair growth is observed, topical treatment can be decreased to every 2 to 4 weeks.

Immunosuppressant therapy

Immunosuppressant and anti-inflammatory therapy serves to stop on-going destruction of the sebaceous glands. Like other inflammatory diseases, most animals receive an initial course to stop the inflammation and treatment is tapered off to the lowest dose that keeps the disease in remission. Oral

may be used. Corticosteroids (e.g. prednisone) are used only if

pruritus Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

is a major clinical feature.

Dietary supplementation

Commonly used dietary supplements include: *

Omega-6 fatty acid Omega-6 fatty acids (also referred to as ω-6 fatty acids or ''n''-6 fatty acids) are a family of polyunsaturated fatty acids that have in common a final carbon-carbon double bond in the ''n''-6 position, that is, the sixth bond, counting from ...

s (e.g., safflower or sunflower oil) *

Omega-3 fatty acid Omega−3 fatty acids, also called Omega-3 oils, ω−3 fatty acids or ''n''−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond, three atoms away from the terminal methyl group in their che ...

s (e.g., fish oils) *

Vitamin A Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably ...

Epidemiology

While the condition has been seen in over 60 breeds of dog (including cross breeds), certain breeds have been found to be more susceptible than others to sebaceous adenitis: *

American Akita The is a historic dog breed of large size originating from the mountains of northern Japan. The two separate varieties of Akita are a pure Japanese strain, commonly called Akita-ken (''ken'' is the on'yomi for ''inu'' meaning dog in Japanese), and ...

and

Akita Inu The is a historic dog breed of large size originating from the mountains of northern Japan. The two separate varieties of Akita are a pure Japanese strain, commonly called Akita-ken (''ken'' is the on'yomi for ''inu'' meaning dog in Japanese), and ...

* Standard Poodle * Vizsla *

English Springer Spaniel The English Springer is a breed of gun dog in the Spaniel group traditionally used for flushing and retrieving game. It is an affectionate, excitable breed with a typical lifespan of twelve to fourteen years. They are very similar to the W ...

Chow Chow 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 ...

* Samoyed *

Weimaraner The Weimaraner ( ) is a large dog that was originally bred as a hunting dog in the early 19th century. Early Weimaraners were used by royalty for hunting large game such as boar, bear and deer. As the popularity of large game hunting began to ...

Havanese Havana (; Spanish: ''La Habana'' ) is the capital and largest city of Cuba. The heart of the La Habana Province, Havana is the country's main port and commercial center.

Breeds also mentioned in scientific literature as having some susceptibility include: *

German Shepherd The German Shepherd or Alsatian is a German breed of working dog of medium to large size. The breed was developed by Max von Stephanitz using various traditional German herding dogs from 1899. It was originally bred as a herding dog, fo ...

* Dachshund *

Old English Sheepdog The Old English Sheepdog is a large breed of dog that emerged in England from early types of herding dog. Obsolete names for the breed include Shepherd's Dog and . The nickname ''Bob-tail'' (or ''Bobtail'') originates from how dogs of the bree ...

Lhasa Apso The Lhasa Apso ( ) is a non-sporting dog breed originating in Tibet. It has traditionally been used as an interior sentinel. Etymology Lhasa is the capital city of Tibet, and ''apso'' is a word from the Tibetan language. There is some deb ...

* Boxer *

Collie Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Man ...

Toy Poodle 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 var ...

* Mixed-breeds Sebaceous adenitis has no sex-predisposition. Sebaceous adenitis also occurs in cats, rabbits, and horses.

Etymology

Sebaceous A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number ...

refers to the gland which is affected by the disease.

Adenitis Adenitis is a general term for an inflammation of a gland. Often it is used to refer to lymphadenitis which is the inflammation of a lymph node. Classification Lymph node adenitis ''Lymph adenitis'' or ''lymph node adenitis'' is caused by infec ...

is a general term referring to the inflammation of a gland.