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Name
Sarcoptic Mange, Canine
Short Description
Sarcoptes scabiei var. canis
Affected Animals: Dogs, cats, foxes, humans, and other mammals.
Overview: Sarcoptic mange is one of the most
uncomfortable skin diseases that a dog can contract. Highly
contagious, sarcoptic mange is caused by a mite called Sarcoptes
scabeie var. canis and is transmissible to humans. These mites
burrow into a host animal's skin, causing scaling, yellowish crust,
hair matting and loss, and severe itching.
Some dogs never develop the classic skin lesions, but will itch
constantly year round. Often, animals with this condition will be
misdiagnosed as having allergies. Diagnosis can be very difficult
because the mites frequently are not found on skin scrapings. Thus,
treatment frequently is based on the suspicion of scabies, rather
than a definitive diagnosis.
Generally, topical dips are used for treatment. Injectable and oral
medications are available, but certain breeds can have a fatal
sensitivity to the medication. A veterinarian should be consulted
about the proper course of treatment. The prognosis for sarcoptic
mange is excellent with proper treatment.
Clinical Signs: Severe, constant pruritus at any time of year is
a classic clinical sign. Areas with less hair are most commonly
affected, including the ears, elbows, ear canals, hocks, ventral
abdomen, chest, and legs. The mites cause alopecia, an erythematous
rash, and yellowish crusts that form on the skin in affected areas.
Typically, the ear margins and elbows are most severely affected.
The animal may develop a secondary pyoderma, severe excoriations,
and sometimes a lymphadenopathy.
Symptoms: Severe, constant itching at any time of year is a
classic symptom of sarcoptic mange. Areas with less hair, such as
the earflaps, elbows, hocks, ventral abdomen, chest, and legs, are
affected most commonly. The mites cause hair loss, a reddened rash,
and yellowish crusts to form on the skin in affected areas.
Typically the ear margins and elbows are affected most severely. The
ear margins tend to have thickened, crusty material on the tips and
yellow scales. The animal may develop a secondary skin infection and
severe scratches from the trauma of constantly scratching. The lymph
nodes also may swell as a result of mite related inflammation.
Description:
Canine scabies is caused by a mite called
Sarcoptes scabiei var. Canis. Although extremely small, these mites
can cause severe itching and skin irritation that will decrease a
dog's quality of life significantly. The female mites dig into the
superficial layers of the skin to lay their eggs. Once the eggs
hatch, the larvae migrate nearby and then dig deeper into the skin
to mature into adults. This process causes severe inflammation,
irritation, itching, and rashes. With a 21-day life cycle, the mites
can replicate quickly, causing a rapid increase in numbers and more
skin irritation over larger areas.
The mites can be passed to other animals, such as cats, foxes, and
humans. People who have acquired mites will develop itchy red bumps
on their body. These lesions last for approximately two weeks, after
which they usually disappear on their own. Repeated contact with the
affected animal can cause the lesions to remain for long periods of
time. A medical dermatologist should be consulted about any human
skin lesions or questions about mites.
Diagnosis:
A definitive diagnosis of sarcoptic mange is
often difficult. Several skin scrapes typically are taken and then
examined under a microscope. Unfortunately, it is often difficult to
detect mites, especially if the animal has had mites for a long time
or has had several recent baths or dips.
Other tests can be used to aid in a diagnosis, such as the pinnal-pedal
reflex test. This test is given by rubbing the ear margin, or pinna,
between the fingers and watching to see if the dog attempts to
scratch the ear with its hind leg. If it does, then scabies is the
presumptive diagnosis. Generally, if scabies is suspected, treatment
should begin immediately. A prompt response to therapy, such as a
decrease in itching, generally means the assumption of sarcoptic
mange was correct.
Prognosis: With proper treatment and prevention, the
prognosis for a cure is excellent.
Transmission or Cause: Canine scabies is highly contagious. It is
commonly transmitted to dogs from other carrier animals, including
other dogs, cats and humans. Transmission occurs through direct
contact with a carrier animal, or when a mite falls off the skin of
a carrier and survives in the environment long enough for it to
infest a new host animal. Mites can survive between four to 21 days
in the environment without a host.
Treatment: For dogs that have thick crusts or a
thick hair coat, treatment begins by clipping the hair from the
affected area. Then, an anti-seborrheic shampoo that breaks down and
removes crusts, skin oil, and debris is applied. Next, a
parasiticidal dip is applied to the entire body, including the face
and ears. The dip should not be allowed to get into the eyes. The
dip typically is used once a week for at least four to six weeks.
The entire environment, including all animals and objects that have
come into contact with a dog that has scabies, should be washed
thoroughly and disinfected.
Other treatments involve the use of an injectable or oral medication
called ivermectin. Although this medication is a highly effective
and common treatment, this use is considered extra-label; it should
NOT be used in breeds such as collies, Shetland sheepdogs, Old
English sheepdogs, and any herding dogs or their crosses. Side
effects can cause death.
The newest treatment for canine sarcoptic mange is selamectin,
manufactured by Pfizer in the United States as Revolution. This
topical parasiticide is effective in treating a number of different
parasitic infestations in dogs and cats. For dogs with scabies, the
treatment is applied topically as a single dose. Sometimes a second
application is administered thirty days later.
All animals that have come into contact with an affected animal need
to be treated as well. A veterinarian should be consulted about the
most appropriate treatment plan. People with suspicious lesions
should consult a medical dermatologist for evaluation and treatment.
Prevention: The best way to prevent transmission is to avoid
any contact with animals or the environment of any animal that may
be carrying scabies. All boarding facilities, grooming equipment,
and bedding materials should be washed thoroughly and disinfected on
a regular basis.
