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Hereditary Autoimmune Diseases

 

Sebaceous Adenitis – Truths and Facts in Akitas

 

The first report on Sebaceous Adenitis (SA) was published in 1985.
SA is a rare inflammatory disease targeting the destruction of the sebaceous glands. The disease has been reported in many different dog breeds, as well as in crossbreeds. Despite this, its construction in the Akita, Poodle, Hovawart, Vizsla and Samoyed is widely known. In the United States, SA-affected dogs were collected in a database maintained by the Orthopedic Foundation of America.

Sebaceous Adenitis

The disease starts with inflammation around the sebaceous glands. These inflammatory processes are not contagious. The inflammations lead to enormous hair loss and Seborrhoea, the most striking feature of which is the bundles of hair with (black) hair root that can be pulled out of the body.

In general, typical external signs of Sebaceous Adenitis are a dull coat, dry and brittle, moth-eaten, and change of dog's scent: they smell like "socks worn three days". The first signs of the disease are subtle and appear on the head, ears and trunk. The hair appears thinner, almost "similar to moth damage". In some cases, the coat color may change.
 

SA does not normally itch unless a secondary skin infection caused by staphylococci is present. Boils can even develop. The therapy mainly focuses on the care of the skin and the avoidance of secondary infections.

As already mentioned, different degrees of inflammation of the skin can be determined by microscopic examination. At the onset of the disease, histopathological findings reveal different cell types of the immune system in the sebaceous glands. The cells were described as perifollicular granulomas (aggregations of a large number of cells). These aggregations consist of defensive cells, macrophages, lymphocytes, plasma cells and neutrophil granulocytes.

Microscopic examinations (histological examination) of skin biopsies have shown that the inflammatory character of SA goes through several stages. Only after complete loss of the sebaceous glands will the intensity of the inflammation decrease.

The etiology of microscopic examination revealed cells or other components of the immune system, which massively participate in the destruction process. However, it has not been proven that bacteria, viruses or other pathogens are the cause of the disease, but all autoimmune reactions are directed at own substances / cells.

As shown by various statistical calculations (Segregation Analysis), new studies show that SA in Akitas follows an autosomal recessive inheritance (*1), a so-called Genodermatosis (*2).

In this context, much attention is paid to pedigrees available from affected and unaffected dogs and their relatives. Environmental factors can be excluded as the main cause of the disease. In addition, SA can be caused by stress, for example during pregnancy or change of owner.

Furthermore, no significant relationships can be derived between the duration of the disease and the degree of SA. It has been found that it is very difficult to figure out what stage of the disease an SA dog is actually in. There are dogs with almost complete destruction of all glands after a span of 2 months. In contrast, a few have been monitored with a destruction of the glands after many years, sometimes as much as 8 to 9 years, and thus comparable to a long dormant process. In any case, it is typical for this disease that it has a very "character of its own".

The reason for the destruction of the sebaceous glands is actually unknown. In any case, no viruses, bacteria or other pathogens have been observed as a primary cause.

 

Research

Due to the etiology of the disease, microscopic examination showed that cells or other components of the immune system participate massively in the destruction process. However, no bacteria, viruses or other pathogens have been shown to be a cause of the disease, but the autoimmune reactions counteract the dog's own substances/cells.

But what exactly causes that "false control" of the immune system?

To date, research has shown that SA positive dogs exhibit "changes" in the blood that cannot be traced and attributed. The blood contains many components of the immune system. Ultimately, these components can be found in the sebaceous glands at a later stage - so the question is:

1. What kind of link/cross-reaction exists between the immune system/blood and the sebaceous glands?
2. What kind of genetic background is responsible for this process?

At the moment, both questions are being examined on the basis of different methodological attempts. The structure of the immune system is very complex and many interactions disappear, so our search is multi-layered. But to discover the genetic key and observe the connections to the triggering causes, a lot of research is needed.

Actually, we are investigating a so-called "Hot Spot" at the genetic level, as this mutation is very prominent in affected dogs. But we need more EDTA blood samples from affected dogs to be able to perform / set up a good "risk assessment".

Subsequently, we need pedigrees of affected dogs, as well as their blood relatives, to investigate the Mendelian inheritance of the disease. We will include this pedigree information in our segregation matrices (statistical calculations) to generate benchmark results.

But without the support of concerned breeders and Akita friends, the progress of the SA research would be unimaginable and we thank everyone who wants to help us.

Translated with permission to part of:

  • PD Dr. Ina Pfeiffer

  • Dipl Biol. Tina Roth

  • dipl. Mathem. Robin Wellmann


Glossary:

*1: Autosomal recessive inheritance:

An abnormal gene on one of each parent's chromosomes is needed to cause the disease. Dogs with only one abnormal gene in the gene pair are called carriers, but because the gene is recessive, they show no signs of the disease. In other words, the normal gene of the pair can provide the function of the gene, so the aberrant gene is described as acting in a recessive manner. Both parents must be carriers for a child to have the symptoms of the disease (sufferer), a child who inherits the gene from one parent will be a carrier.

*2 : Genodermatosis:
A skin condition with genetic origin

Vogt-Koyanaga-Harada Disease, better known as VKH syndrome

 

VKH is an autoimmune disease, ie autoimmune related with hereditary implications. It is believed that any kind of stress can trigger the disease. Symptoms include depigmentation, hair loss and blindness.

Sometimes there are no warnings, but in most cases there are, with depigmentation and conjunctivitis (affecting the whites of the eyes and red eye rims) as the main features. Conjunctivitis is often followed by a detached retina, with a milky blue surface coloring the eyeball. This is truly a medical emergency. Without treatment, blindness will follow. The dog is in great pain. The disease affects mucosal areas such as the eyelids, mouth, anus, vulva and sometimes the soles of the dog's feet. There is a clearly visible loss of pigmentation in these areas, from which it often starts with crusting or blistering. The severity of symptoms vary from dog to dog. An interesting point to note is that dogs are most commonly affected at the age of 18 to 20 months. There is no cure, and there are no methods of testing breeding stock for VKH.

Uveodermatological Syndrome (UDS) / VKH

The actual VKH syndrome is a human disease, well described for almost a hundred years. A similar disease is known in the dog, but because we do not know what the relationship between the dog and the human disease is, it is doubted to also call the canine variant "VKH syndrome". Until we know what's really going on in the dog, we'll leave it at VKH-like syndrome, or rather, uveodermatological syndrome (UDS). This is a very disturbing disease mainly found in Akitas. As a lover and/or breeder of Akitas you will probably hear or read about them at some point. There is no race or gender preference in this disease, but it can strike at any time with no apparent trigger. It is a genetic problem and as such certain 'lines' will carry it, which is not to say that if you have an Akita from an affected line you can say with certainty that it will show up in your dog.

Draw
It is mainly an eye and skin disease, in which various signs can be observed. The cases are not always clearly described, there is a wide variation in how it manifests itself. It can be a sudden onset with multiple signs or a more insidious onset with various forms of conditions. UDS will attack the body itself and is therefore seen as an autoimmune disease (similar to rheumatoid arthritis). In all cases, the pigment cells in the body are attacked. Therefore, you will always be able to observe the various signs of eye irritation and loss of pigment of dark-toned skin.

 

Eye 
If the disease is concentrated on the eye, it is most likely that the disease will result in death.
  The 'attack' focuses with the main target on the iris, with the result that the dog will suffer from a very painful internal eye infection. In fact, it is an inflammation of the iris and presents as a very small pupil with a swollen iris with especially conjunctivitis. Often this is the point of misdiagnosis, as it simply resembles conjunctivitis (=conjunctivitis). If not discussed in detail, this can lead to a delayed diagnosis and a failing treatment plan at a later stage. There will be very strong engorgement in the scleral blood vessels around the eyes and therefore the white area will appear as 'bloodshot'. Also, the dog will show signs of pain and will close his eyes in bright light. In addition, a watery discharge may be noted. As already mentioned, the eyes will be very painful and uveitis is the main problem of the disease. The retina is affected and often retinal detachment will occur. Whether it's a large complete detachment (with blindness and bleeding, irreversible and often leading to euthanasia), or smaller less obvious retinal detachments (these cause gray streaks on the retina and can be signs of UDS), uveitis can lead to glaucoma and blindness . Since uveitis is very painful and retinal detachment can lead to blindness, both cases, if left untreated, often for the well-being of the dog, will lead to euthanasia. Correct diagnosis at an early stage is extremely important. The signs are clear, so if diagnosed too late or incorrectly, treatment will be useless and the 'damage' already present cannot be reversed. If the dog has ongoing uveitis and does not respond to treatment then the only real option is euthanasia, as 'stretching' is incredibly painful for the dog and painful for the owner(s) to watch.


Skin
This is a somewhat more obvious sign, not normally the cause of death and morbidity. The black and pigmented skin and coat, especially around the muzzle and eyelids, often begin to look 'washed out' and eventually turn brown. Skin biopsies will be able to provide a diagnosis of UDS/VKH, especially in combination with existing eye problems. UDS is primarily an ocular disease, but the affected skin is evident, emerging at the end of the course of the disease or early in the first stage. The eye signs are the most disturbing, but often misinterpreted. With proper treatment, a life without pain and symptoms can be maintained, but rarely for more than 18 months. Some dogs are more likely to succumb if the uveitis and subsequent damage become too extensive (and irreversible). There are several drugs that can be used, including Vitamin E, Oxytetracyclin, and Niacinamide, but the efficacy of these drugs is debatable.

Finally, we would like to emphasize once again that early detection and the right treatment plan is crucial and can mean the difference between life and death for your dog!

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