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 This
condition develops in some, but not all dogs that have been bred
for unusual coat color, especially
Fawn - a dilution of a chocolate/rust coat & Blue - a dilution
of the black/tan coat color.
Alopecia means
hairlessness - affected dogs have a poor, patchy haircoat progressing
to widespread permanent hair loss. At the cellular level, there
are abnormalities of the hair follicles and uneven clumping of pigment
(melanin) granules in the hair shafts in affected areas.
The
inheritance is unclear. The condition is thought to be due to the
interaction of different factors at the gene position for color.
It is not simply determined by the genes at that locus, because
not all dogs with color dilution develop coat problems.
Dogs
with this condition are born with a normal hair coat. Those with
lighter blue or fawn hair coats usually start to show changes by
6 months while in dogs with darker steel blue coats, the changes
may not be evident until 2 or 3 years of age. The dog will experience
hair loss and dry skin. Sometimes the earliest sign is a recurring
bacterial infection (folliculitis), generally on the back, where
you will see small bumps which are infected hair follicles. This
clears up temporarily with antibiotics, but the affected area is
very slow to regrow hair, or remains hairless.
Hair
loss is usually first apparent on the back and by 2 or 3 years has
spread over all the light colored areas of the body. The exposed
skin is often scaly and is susceptible to sunburn or extreme cold.
The dog's health is not otherwise affected by this condition.
A
veterinarian may suspect this disorder if your dog has typical hair
coat changes and is an unusual color for the breed. The diagnosis
is confirmed through microscopic examination of plucked hairs or
a skin biopsy. The latter is a simple procedure, done with local
anesthetic, in which a veterinarian removes a small sample of the
dog's skin for examination by a veterinary pathologist. The biopsy
will show changes characteristic of this condition.
Careful
microscopic examination of plucked hairs will show large clumps
of melanin distributed unevenly along the hair shaft.
In
young dogs, demodicosis or other inherited hair defects should be
considered while in dogs with a later onset (2 to 3 years of age),
endocrine disorders (particularly hypothyroidism) should be ruled
out.
A
dog can lead a normal healthy life with periodic symptomatic treatment
as needed - moisturizing rinses for dry scaly skin or antibiotics
for bacterial infections.
Since
early hair loss occurs due to breakage, to slow the rate of loss
avoid harsh shampoos and vigorous grooming.
There
have been some early reports of hair re-growth using etretinate
treatment.
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