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Almost every dog owner has heard of, if not seen, a “hot spot.” This
slang term describes a host of skin disorders (summer sores, moist
eczema, acute moist dermatitis and pyotraumatic dermatitis) that
have one common feature – dogs can’t leave them alone.
No
matter what the trigger for skin irritation, the dog’s response is
the same – to lick, bite or scratch the site while trying to soothe
it. Unfortunately, this aggravates the skin further and the site
becomes more irritated (pruritic), which makes the dog lick, bite
and scratch with more intensity.
As
inflammation builds, the skin’s superficial layer (the dermis) loses
its impermeability. Fluid rich in nutrients oozes through the
surface, providing the perfect environment for bacteria to multiply.
Ultimately, this leads to the formation of a hot spot – a reddened,
raw-looking area of thickened, infected skin.
Triggers
Though the end point of this self-perpetuating cycle is always the
same, several factors contribute to its onset. The main players in
this drama are bacteria, inflammation and moisture.
Bacteria flourish in every hot spot. As soon as the skin’s natural
defences drop, bacteria that are normal residents of the skin,
typically staphylococcus (staph), grow. Infection causes more
pruritis, which stimulates more licking.
In
some dogs, a focal skin infection can be a trigger for a hot spot.
In such a case, the infection causes itchiness that initiates
self-trauma and inflammation.
The
main suppressor of skin immunity is inflammation. A minor trauma
such as a scratch or abrasion can initiate inflammation that leads
to a hot spot. More commonly, inflammation is generated by reactions
to food, fleas or inhaled (atopic) allergens (such as pollen and
house dust) that cause histamine release in the skin surface.
Inflammation not only sets the stage for infection, it initiates
pruritis that stimulates dogs to lick and bite.
Moisture is another factor that compromises the natural defences of
the skin, allowing bacteria to multiply. For this reason,
veterinarians see more hot spots during rainy, humid weather than
during dry weather. Bathing or swimming can also predispose a dog to
hot spots.
Certain breeds are more prone than others to developing hot spots.
Golden Retrievers tend to develop superficial, easily treated hot
spots that are triggered by allergy-induced inflammation. In
contrast, German Shepherd Dogs tend to get primary skin infections
that initiate the inflammatory processes leading to hot-spot
formation. In this breed, bacteria are quicker to penetrate deep
into the skin layers, so hot spot treatment is more complicated.
Treatment
How
will your veterinarian manage a hot spot? First, he will shave the
fur over the entire affected area. This is a necessary step in
assessing the size and severity of a hot spot (which can be masked
by hair). Because clipping and treating a hot spot can be very
painful, some dogs need to be tranquilized (or even anaesthetized)
before the task can be performed.
Once
the site is shaved, your veterinarian will clean it by scrubbing the
area with an antibacterial soap to remove the liquid and crusted
exudates and expose the skin surface. Alternatively, he may employ
hydrotherapy, especially if the site is particularly painful to
touch. Hydrotherapy involves spraying the site with body-temperature
water for about 10 minutes, with a hose or water sprayer. This
procedure not only cleans the skin, but also stimulates blood flow
to the site.
Frequent cleansing of a hot spot, even every few hours on the first
day, significantly speeds healing.
Once
the site is clean, your veterinarian will pat the skin dry and apply
a topical antibacterial ointment, or one that has an antibiotic as
well as a steroid to decrease the inflammation. To be beneficial,
the ointment must contact the skin surface, so preliminary cleaning
is vital.
In
some cases, a hot spot is deeply infected or so inflamed that a dog
continues to be irritated despite treatment. In the former case, the
patient needs oral antibiotics, and in the latter, oral steroid
therapy is required to get the inflammation in check.
Topical management, cleaning and ointment application, as well as
oral medications (if indicated) must be continued at home. After two
days of treatment, most hot spots look markedly better, but a few
may take a week to finally look like they’re going to heal. Once the
oozing has ceased, the cleaning frequency can be decreased, but
ointment should still be applied on a regular basis.
A
hot spot recognized very early in its development when it’s
superficial may be possible to successfully treat without shaving
the dog’s fur. The trick is to clean the skin well to remove
secretions, then thoroughly dry it. A steroid-containing
antibacterial ointment is then applied at least twice a day.
Prevention
Hot
spots can be prevented by addressing the factors that trigger their
formation. To improve skin health and its ability to keep bacteria
in check, most veterinarians recommend a high-quality diet for their
patients.
When
fleas are an inciting cause of inflammation, regular flea control is
needed. Dogs should be treated with a topical product that will kill
fleas before they have a chance to bite and set off an allergic
reaction.
A
dog with a food allergy that predisposes him to hot spots should be
fed a hypoallergenic diet. Veterinarians prescribe special diets
with novel protein sources such as fish, venison or pinto beans, to
name a few.
When
a dog suffers from recurrent hot spots due to atopic allergies,
antihistamines can sometimes control skin inflammation. Adding
supplemental omega fatty acids can also help reduce skin
inflammation from allergic reactions. Salmon oil is rich in these
particular fatty acids. According to Dr. John Angus, a dermatologist
in
Arizona, the daily dose
is one 1,000-milligram capsule for each 4.5 kilograms (10 pounds)
body weight.
Several prescription foods made for dogs with skin allergies contain
extra omega fatty acids. During their allergy seasons, some dogs are
managed with steroids to reduce skin inflammation, while others are
given injections to hyposensitize them to specific allergens.
If
hot spots are occurring after a dog gets wet, the solution is simple
– dry him well after bathing or swimming. A vigorous towelling may
be adequate, but for long-haired dogs, a hairdryer is often needed.
Some owners trim the long hair on their dog’s belly (where it can’t
be seen) to make drying easier. During the summer, it may be
beneficial to clip a dog’s hair very short over his entire body.
The
best defence against hot spots is to be on the lookout for them. If
your dog is paying too much attention to a specific site on his
body, or if you find some fur that’s wet with saliva, investigate
it. You may be able to clean and dry the area before it becomes
inflamed and infected.
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