Sarcoptic Mange (Canine)
Canine sarcoptic mange, or scabies, is caused by a tiny mite that burrows into the skin and causes intense itching and hair loss in dogs. The mite is fairly host specific, but it can cause temporary skin lesions in humans and other animals. This highly contagious disease is usually spread by direct contact with an infected dog or infested environment. The hair loss is first seen on the ears, elbows, hocks, ventral chest and abdomen and is accompanied by itching, reddened papules and crusts that can eventually appear over the entire body. Diagnosis can be difficult and is often confirmed by therapy to see if the lesions clear up. There are several treatments available and the prognosis is excellent for recovery.
Common name: Scabies
Scientific name: Scabies, Canine sarcoptic mange
Sarcoptic mange affects all dogs of all ages, breeds and sexes, but may be more severe in young animals. It may appear as a self limiting disease in other species, including humans because the mite can only maintain its life cycle and reproduce on dog skin. This means the disease will usually resolve on its own within two weeks if continued contact with the infected dog or environment is not maintained.
The exact incidence or prevalence of sarcoptic mange appears to be unknown, but it is not uncommon.
Sarcoptic mange is found worldwide.
Clinical signs (primary, most to least frequent, scientific term, synonyms)
Alopecia (hair loss) starting on ears, elbows, hocks, ventral chest and abdomen, Pruritis (intense itching), Reddened papules and crusts on skin.
Clinical signs (secondary, most to least frequent, scientific term, synonyms)
Thickening of the skin, General poor health.
Cause (scientific, common term)
Sarcoptes scabiei var canis.
Organ system affected (most to least affected)
Skin, Hair coat.
Skin scrape (several may be necessary to demonstrate the mite), Fecal flotation (demonstrate mites in the stool swallowed while chewing), Treatment trial (to see if it responds to therapy), Positive pinnal pedal reflex (rub the affected ear flap between the fingers and dog will scratch at the ear with the hind leg).
Atopy (inhalant allergy affecting the skin), Flea allergy dermatitis, Food allergy, Dermatitis nonspecific, Demodectic mange.
Canine Sarcoptic Mange, otherwise known as scabies, is a skin disease that is caused by a tiny mite that burrows into the skin and causes intense itching and hair loss. This highly contagious disease is found worldwide and occurs in all breeds, sexes and ages of dogs, but may be more severe in young puppies. The mite is considered fairly host specific because it only reproduces and completes its life cycle on dog skin, but it can cause temporary skin lesions in humans and other animals. It is most commonly transmitted by direct contact with an infected dog or an infested environment. It usually takes about a week for the first signs to appear after contact with an infected source. The hair loss is first seen on the ears, elbows, ventral chest, abdomen and hocks, and is accompanied by intense itching and the appearance of reddened papules and crusts. The lesions can spread over the entire body in severe cases, resulting in extensive hair loss, secondary bacterial and yeast infections, and overall debilitation and emaciation. Skin scrapings are commonly used to reveal the mites and reach a diagnosis, but they may be difficult to find because the mites burrow deep in the skin. Other common diagnostic tools include fecal flotations to show mites in the stool or demonstration of a positive pinnal pedal reflex, which is elicited by rubbing the affected ear of the dog between the fingers and observing a scratching reflex of the hind leg. Finally, many veterinarians confirm the diagnosis by performing a treatment trial to see if skin lesions resolve. Sarcoptic mange must be differentiated from several other skin diseases, including flea allergy dermatitis, atopy (inhalant skin allergy) and food allergies.
Scabies can be treated with weekly topical applications of dips containing amitraz, phosmet or lime sulfur. It is important to follow the directions provided by a veterinarian for the proper preparation, application and disposal of the dip.
Veterinarians also treat scabies with injections of ivermectin or oral doses of selamectin or milbemycin. Some of these treatments are not approved for use in dogs by the FDA but have proven to be highly effective in clinical trials and are commonly used. In some cases antibiotics and small doses of glucocorticoids may also be prescribed to control secondary bacterial infections, inflammation and itching.
Infected dogs should be isolated from other animals to prevent disease transmission, and animals who live in the same household or who have had contact with the infected dog should be treated. Although the mites generally live off the dog for only 48 hours, any bedding should be laundered in hot water, soap and bleach because environmental contamination can result in repeated disease transmission. Humans with itchy red spots or other skin lesions should consult their physician.
The prognosis for recovery is excellent in animals that are otherwise healthy and treated appropriately.
Sarcoptic mange may be treated at home with products labeled for such use. Unresponsive or otherwise complicated cases require veterinary care.
Case, Linda External Parasites In: The Dog Its Behavior, Nutrition and Health Ames, Iowa, published by Iowa State Press 1999 pp 255-6
Foil, Carol S. Update on Treating Scabies and Cheyletiella In: Western Veterinary Conference 2003
Kahn, Cynthia ed. Merck Veterinary Manual Ninth Edition Whitehouse Station, NJ published by Merck and Co Inc 2005 pp 746
Mueller, Ralf S in Dermatology for the Small Animal Practitioner by Hills Jackson, WY published by Teton NewMedia pp 49, 54
Lila Miller, DVM
Steven Hansen, DVM, MS, MBA