Scabies, also known as sarcoptic mange, is a cruel skin disease that makes affected dogs feel even worse than they look. The mites that cause it are present everywhere dogs are found, regardless of climate. Scabies is treatable but the earlier you catch it, the better your chance of permanently stopping it, its complications and risk of recurrence. If you notice your dog scratching himself so vigorously that he's drawing blood and wearing fur away, get him to the vet as soon as possible.
The Misery of Scabies
Many different species of mites, microscopic parasites related to spiders, exist, but most only survive on specific hosts. Dogs contract scabies after a female Sarcoptes mite tunnels into their skin, laying eggs as she goes. This triggers an allergic reaction that becomes much worse after the eggs hatch. As mite populations skyrocket and spread, burrowing new tunnels and feeding on the dog's skin, new lesions develop, their itchiness often compounded by bacterial infections that invade the broken skin. Typically, scabies starts on parts of the body with the least fur, such as earflaps, the abdomen and elbows. Left untreated, scabies lesions can cover most of your dog's body.
Often a Diagnostic Challenge
Ideally, a vet diagnoses scabies by scraping a little skin from a lesion, examining it under a microscope and seeing the mites, but that's not always how it works in practice. The reason: Dogs claw at their skin so fiercely that they break open the tunnels where the mites have established themselves, thereby killing them. In fact, fewer than half of all skin scrapings of dogs with scabies reveal the presence of mites. Since a negative skin scrape doesn't rule out a scabies diagnosis, many vets prefer to conduct a "maybe mange" test, says veterinarian Wendy Brooks, educational director for VeterinaryPartner.com. In other words, when a vet suspects scabies, she might start to treat the dog for that before being certain. If she's right, symptoms will start to improve.
How Vets Treat Scabies
In the past, high doses of the anti-parasitic drug ivermectin, injected weekly or every two weeks, were standard veterinary treatment for scabies. However, even though ivermectin is effective, it can be toxic to some dogs and breeds, especially those in the collie family. Many vets now frown upon using it. Other newer drugs, some derived from ivermectin, do the job with less risk of nasty side effects. In addition to administering mite-killing drugs, the vet may prescribe anti-inflammatories such as cortisone, to be taken orally, applied to the skin or both, to relieve itchiness. Antibiotics will be used to treat skin infections. Though the dog should start feeling more comfortable right away, treatment typically continues for four to six weeks, depending upon the severity of the condition.
On the Home Front
Scabies is easily transmitted between dogs so in households with more than one, all must be treated, even if the others show no symptoms. While dog mites can't live permanently on human skin, they can make their presence felt in the form of an itchy, bumpy red rash. The rash usually clears up on its own after a couple of weeks. The indoor environment, including the dog's bedding, any furniture he likes to lie on and grooming tools, must be thoroughly cleaned and disinfected. Bathing your dog with medicated shampoos will help break up crusts and debris on his skin. Once-a-week dips used to be recommended for killing parasites on the surface of the skin but these were difficult for owners to manage, not to mention unpopular with dogs. Other topical medications are in more widespread use today.