Alice Crook, DVM Coordinator, Sir James Dunn Animal
Welfare Centre
Atlantic Veterinary College University of Prince Edward Island
Sebaceous
Adenitis (S.A.)
By Judy King
Sebaceous Adenitis
is a hereditary autoimmune skin disease whose mode of Inheritance is
believed to be simple autosomal recessive, requiring a single Defective
gene from both sire and dam. SA is not sex linked. A genetic disease
of this type cannot be cured, but can be treated and most definitely can
be bred away from.
SA has been diagnosed
in many breeds including Airedale, Akita, Chow Chow, Collie, Dalmatian,
Dachshund, German Shepherd, Golden Retriever, Irish Setter, Lhasa
Apso, Maltese, Miniature Pinscher, Old English Sheepdog, Pomeranian,
Poodle, Samoyed, Springer Spaniel, St. Bernard, Vizsla, and Weimaraner,
as well as in mixed breeds. Sebaceous Adenitis is most frequently
seen in younger dogs but does effect dogs of senior age as well. A parent
of a SA dog may or may not show clinical symptoms, being what is known
as subclinically affected, meaning that some inflammation may exist but
has not progressed to destruction of the glands and the subsequent loss
of hair. They may have been described as having some skin allergies, but
they are carriers none the less.
In SA the
sebaceous glands that adjoin the hair follicles become inflamed and
gradually are destroyed. Symptoms of SA can resemble allergies and
can often go improperly diagnosed for some time. The most common symptoms
are excessive dandruff (scaling) and hair loss, which can be from moderate
to severe. The hair loss is usually patchy, giving a moth-eaten look.
Itchiness is not indicative of SA, but can accompany secondary skin infections,
which can flare up and are often accompanied by a musty odor. The treatment
includes antibiotics when secondary skin infections are present.
Accurate diagnosis
requires punch biopsy. A local anesthetic is injected into the site
to be biopsied (usually near the withers or affected area). When the
area is numb, a tiny 6mm Baker's biopsy punch is used to remove a tiny
plug of skin. Usually only one to two sutures are needed to close the
biopsy site. The sample will then be gently placed (without squeezing)
in formalin and sent for evaluation by a dermatopathologist.
In Akita's, systemic
illness (weight loss and fever) appears more common and is suspect
as being indicative of a secondary underlying disease/condition. However,
this is not to say all SA-affected Akita's have accompanying ill health.
Many owners have claimed relative ease of maintenance of their SA-affected
Akita, provided they stay on top of the situation by careful monitoring
the condition of the skin and the overall appearance of their Akita's
health.
Currently there
is no cure for SA but with good care, the affected dog can be comfortable,
healthy, happy, and capable of giving and receiving love just as before
developing SA. Dogs with SA can live happy lives free of pain and suffering.
Treatment is relatively inexpensive, the most difficult aspect of SA
usually being a cosmetic one. Some recommend oil baths, rubbing well
into the skin a non-perfumed oil (baby oil, bath oil i.e., Alpha Keri,
and Redken products have proven beneficial) to ensure saturation and allowing
it to soak into the skin for about an hour. The oil loosens the scales
and lubricates skin compromised by the absence of sebaceous oil glands.
Palmolive dish-washing
detergent is good for removing the oil, and often requires several
shampoos. Finish with a mild dog shampoo and creme rinse. Repeat this
procedure bi-weekly or monthly as needed. Some dogs grow new hair after
treatment; others do not. The hair loss and regrowth is cyclical. Many
Akita owners have disclaimed this treatment, not having seen significant
improvement, preferring instead to gently brush affected areas a few
times a week with a very soft bristle brush, thus removing the scales
that harbor bacteria, which can lead to secondary, skin infections. How
can we rid our breed of this disease? We now understand with certainty
the mode of inheritance. We can strive to breed away from this disease by
using the objective diagnostic protocol on breeding stock.
We
can register affected dogs with the GDC (Institute for Genetic Disease
Control in Animals), P.O. Box 222, Davis, CA 95617; Phone: 916-756-6773.
We can participate freely with the Open Registry for SA and share our
knowledge of the mode of inheritance with other breeders and owners.
Last, but not least, (and
the point of this page) you can contribute to SA research by purchasing
the '98 Challenge Pin. Funds from the sale of the '98 pin are dedicated
toward SA research. To receive updates about SA research,
subscribe to Progress in SA Research, published by GRF (Genodermatosis
Research Foundation). Write to 1635 Grange Hall Road, Dayton, OH, 45432
USA or phone 513-426-7060 for subscription information. Please note: The author gives permission
for and encourages distribution of this article for education purposes.
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Sebaceous Adenitis
By: Dr. Rosanna Marsalla
http://www.petplace.com
Section: Overview
Open Image Viewer. Sebaceous adenitis is an uncommon
skin disease of dogs that is genetically inherited and runs in families.
Poodles, Akitas, Samoyeds and Vizlas are at increased risk for this condition,
but it has been reported in other breeds and in mixed breed dogs.
The exact cause is not
known, but it may be caused by an attack of the immune system against
the sebaceous glands responsible for the production of sebum (oil) on
the skin. As a consequence, the skin becomes dry and scaly and loses the
hair (alopecia). Some dogs may develop skin infection as a consequence of
the abnormal skin oil and may become itchy because of the skin infection.
Skin infections manifest with odor, papules (red bumps) and excessive shedding.
The disease starts on
top of the head and spreads to the rest of the body. It starts when
dogs are one to three years of age and tends to get progressively worse
with time.
Screening can be done
in dogs belonging to breeds at increased risk for this disease to identify
individuals carrying the disease. Biopsies taken from clinically normal
skin may already reveal changes suggestive of the condition. Dogs carrying
the disease should be excluded from breeding programs due to the genetic
nature of this condition.
Diagnosis
Other skin diseases
may look similar to sebaceous adenitis and must be ruled out by appropriate
testing.
Demodicosis is a much
more common condition that could also cause hair loss and scaling. For
this reason, skin scrapings are done to rule out this type of mange.
Many dogs with sebaceous
adenitis have a concurrent skin infection. Cytology – tape impressions
of the skin stained to reveal bacteria and yeast – should be done to
determine the type and severity of the skin infection.
The final diagnosis
of sebaceous adenitis is made by histopathology, so skin biopsies are
normally taken. Since the changes seen with this condition may not be
present in all the areas, it is important that several biopsies are taken.
Stitches are places in the biopsy sites to ensure fast and proper healing.
Home Care
There is no definite
cure for this condition. However, several topical and systemic treatments
can be tried to decrease the clinical signs.
You may need to bathe
your dog several times a week using medicated shampoos to soothe the
skin and remove the excessive scaling. You will also have to use medicated
shampoos (Oxydex) to help speed the recovery from skin infections.
Systemic medications
are given to eliminate skin infections and normalize the sebum production.
The most popular medications used for this condition are retinoids. They
are quite expensive and have the potential for serious adverse effects.
They are teratogenic, which means they have the potential to cause fetal
malformation in pregnant animals, thus they should not be used in breeding
animals. As they accumulate in the fat for a long time, the teratogenic
effect persists for several months after the discontinuation of the therapy.
This type of medication should be tried for at least two months before
assessment of the efficacy is made. The most commonly used retinoid is
Accutane (isotretinoin).
For dogs that do not
respond to retinoids, other medications may be tried. Cyclosporines have
been effective in a few refractory cases. This medication is immunosuppressive,
which means it suppresses the reaction of the immune system, and therefore
has the potential to increase the risk for bacterial infections. Your dog
should be closely monitored for adverse effects including vomiting, diarrhea,
liver and kidney disease.
Information
In-depth
Sebaceous adenitis is an inflammatory disease of the sebaceous
(oil) glands leading to the destruction of the glands. Vizlas, Akitas,
poodles and Samoyeds are predisposed and the exact pathogenesis has not
been established. It seems to be a genetically inherited defect and young
dogs are usually affected.
In Poodles, it is believed to be an autosomal recessive mode of
inheritance due to the fact that 25 percent of affected dogs may be
sub-clinical. Several theories have been formulated to explain this condition:
According to one theory the disease is auto-immune in nature and
the sebaceous glands are targeted by the immune system and destroyed.
Another theory is that the destruction of the sebaceous glands
is secondary to a disease of keratinization, which leads to obstruction
of the duct and ultimately disappearance of the glands.
It is also hypothesized that both the adenitis and the keratinization
defects are secondary to an imbalance in lipid metabolism.
Related Symptoms or Ailments
Bacterial folliculitis (superficial pyoderma)
Demodex
Dermatophytosis (ringworm)
Disease of keratinization
Mycosis fungoides
Endocrinopathies (diseases of the endocrine system)
Pemphigus foliaceous
Follicular dysplasia
Deep skin scrapings should be done in any dog with these clinical
signs to rule out demodicosis.
Veterinary Care In-depth
Open Image Viewer
Diagnosis In-depth
The early lesions include alopecia (hair loss) with excess scaling
and brittle hairs. The top of the head, the dorsal planum of the nose,
dorsal neck and dorsal midline are commonly affected areas.
Sebaceous adenitits has a cyclic pattern in some dogs with periods
of improvement and worsening. Symptoms are slightly different according
to the type of hair coat:
In short coated breeds (Vizlas), circular areas of alopecia with
fine, white, non-adhering scaling are commonly the first manifestation
of the disease. Infections are not common in these dogs and itchiness
is usually not present.
In poodles, the scales are tightly adherent and follicular casts
– accumulations of keratinous debris around the hair shaft seen protruding
from the follicle – are visible.
In Akitas, seborrhea oleosa is usually the first sign. Greasy,
yellow follicular casts are common.These animals tend to get systemically
ill. Concurrent epilepsy has been reported in some dogs. Secondary bacterial
infection is common, causing itchiness.
In Samoyeds the most severe sign is alopecia on the trunk with
follicular casts.
Diagnosis of sebaceous adenitis is made by histopathology, and
several biopsies may be needed to make a final diagnosis. Biopsies should
be taken from affected and non-affected skin. Subtle early lesions are
most useful to document active inflammation.
Secondary bacterial infection and Malassezia dermatitis are commonly
present at the time of initial evaluation. Cytology is important to determine
the type and severity of the infection. Infections should be cleared
before skin biopsies are taken to minimize secondary non-specific changes.
Pathological changes of the tissue vary according to the stage
of the disease.
At the beginning, a nodular inflammation targeting the sebaceous
glands is evident. Discrete nodules of histiocytes, neutrophils and lymphocytes
are seen at the site of sebaceous glands. One disease that can appear
similar to the inflammatory stage of sebaceous adenitis is the sterile
pyogranuloma syndrome. However, in the latter, the inflammation is less
focused on the sebaceous glands and clinically it has raised firm nodules
rather than with scaling and alopecia.
As the disease progresses, the inflammation decreases until sebaceous
glands are no longer evident.
When biopsy samples are submitted, pathologists should be made
aware of the suspicion of sebaceous adenitis so that multiple biopsy sections
are prepared and special attention is paid to the number and shape of the
sebaceous glands.
Treatment In-depth
Treatments include anti-seborrheic shampoos, emollients, essential
fatty acids, antibiotics for the secondary bacterial folliculitis, and
retinoids.
Topical therapy:
Keratolytic shampoos are helpful in mild cases. The most commonly
used include a combination of sulfur and salycilic acid. Alternately,
antibacterial products like benzoyl peroxide in combination with sulfur
(OxyDex) may be beneficial.
Topical propylene glycol (50 to 75 percent) diluted with water
is also effective to decrease the scaling. It is used as a spray once
or twice daily.
Soaks with baby oil have also been reported to help in severely
affected dogs. Dogs need to be shampooed several times to remove the
oil from the skin.
Systemic Therapy:
Essential fatty acids at high doses
Evening primrose oil at 500 mg twice daily orally
Eicosapentaenoic acid at 180 mg per 10lb of body weight daily
orally
Retinoids in refractory cases, due to their ability of modulating
epidermal growth and differentiation. Retinoids should be given for
a minimum of two months. Outcome cannot be predicted on the basis of clinical
signs or histologic findings and a prognosis cannot be determined on the
basis of whether sebaceous glands are evident histologically.
Toxicity in animals seems to be less severe than in humans. Adverse
effects include: vomiting, diarrhea, erythema, keratoconjunctivitis
and stiffness.
Isotretinoin (Accutane) has been reported to be very successful
in Vizlas with sebaceous adenitis. Isotretinoin has marked sebostatic
activity. It decreases the proliferation of basal sebocytes and it suppresses
sebum (oil) production. Other retinoids have been reported to be only
moderately successful.
Cyclosporines (Sandimmune) have been used in a few cases with
good success. In some dogs, good clinical response is observed in spite
of absence of sebaceous glands histologically. Although cyclosporine has
immunosuppressive properties (strong inhibitory effect on lymphocyte proliferation),
this drug also has inhibitory effects of keratinocyte proliferation, which
may be beneficial in some cases. Adverse effects include: vomiting, diarrhea,
gingival hyperplasia, kidney toxicity, liver toxicity and increased incidence
of bacterial infections.
Systemic antibiotics may be necessary for four to six weeks.
Follow-up
This condition is genetic and can be prevented by identifying
affected animals and carriers and eliminating these animals from the
breeding program.
This is a lifelong condition, thus chronic maintenance therapy
(both topical and systemic) is necessary.
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