Sarcoptic Mange - Very Common Cause of Intense Itching and Skin Disease in Dogs
Sarcoptic mange is a very contagious disease caused by the mite Sarcoptes scabiei var.canis. It gets its name from the Latin word scabere which means to scratch. Scabies mites have a 17- to-21-day life cycle. The female mite excavates a burrow in the skin and lays her eggs behind her. This usually presents as an incredibly pruritic (Itchy) process. Papules, scales and heavy serous crusting are commonly detectable at the elbows, hocks, face and pinnae and ventral trunk in dogs.
Foxes with mange are often very thin, have a sparse, rough haircoat and are missing their tail hair. Sarcoptic mange can also present as "Scabies incognito", manifested by severe pruritus without lesions.
Diagnosis of sarcoptic mange is made via superficial skin scrapings. The mites may be difficult to find. So the diagnosis is often made via trial therapy for mites.
Selamectin (Revolution) is the only product licensed as a topical spot-on formulation for the control and treatment of canine scabies.
Ivermectin can also be given by subcutaneous injection, orally or topically.
Milbemycin oxime can also be effective for canine scabies.
Topical dips/rinses that can be used are lime sulfur rinses and amitraz rinses.
These mites are highly contagious, all in contact animals should be treated.
Most importantly, this is not a rare disease. I see at least several cases per month and have now seen several human cases as well. I attribute this to the high density of foxes which carry the parasite. Any animal with severe, unrelenting itching should be checked for this ectoparasite.
Lesions on people consist of papules within 24 hours of exposure accompanied by pruritus. Canine scabies mites on a person are difficult to isolate. Although they burrow, they will only remain on the unpreferred host for a few hours to a few days. Pruritus can persist for several weeks following eradication of the mite.
Canine scabies have been found living on cats affected with mites. The off-host survival time is temperature and humidity dependent. At room temperature, all mite stages can survive two to six days. Female mites at low temperature and high humidity can survive off-host for four to 21 days. The incubation period is unknown but severe pruritus is evident at 21-30 days.
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