I commonly get questions from owners after their dogs have been recently diagnosed with mange. I usually get blank looks to my inevitable response, "What type of mange?" Their answers are typically, "There’s more than one?" and "Does it matter?" On both counts, the answer is "yes."
Here’s a primer on the two most common types of mange in dogs — sarcoptic and demodectic — in compare and contrast style.
Sarcoptic Mange — infection of the skin with the microscopic, parasitic mite Sarcoptes scabei. Sarcoptic mange is contagious, and most dogs catch the disease via direct contact with an infected individual. People and cats can also be transiently infected.
Demodectic Mange — overgrowth of mites, Demodex sp., that are normally found in small numbers in a dog’s skin. Demodectic mange is usually diagnosed in young dogs without fully functioning immune systems, or in dogs that are otherwise immunocompromised. Demodectic mange is not contagious.
Sarcoptic Mange — extreme itchiness with hair loss and red scaly skin that typically start in sparsely-haired areas like the ear flaps, elbows, and abdomen, but can spread to the entire body without effective treatment.
Demodectic Mange — patchy hair loss with relatively normal looking skin underneath is the hallmark of the most common, localized form of the demodectic mange. Mild to moderate itching may or may not be present. In more severe, generalized cases, hair loss may be wide-spread, the skin obviously abnormal, and itchiness severe.
Sarcoptic Mange — if skin scrapings reveal the mite, a diagnosis of sarcoptic mange is easily reached. However, dogs may react so intensely to a small number of mites that skin scrapings can be falsely negative. A tentative diagnosis is often reached based on a dog’s clinical signs and response to treatment.
Demodectic Mange — multiple skin scrapings usually will reveal the presence of higher than normal numbers of mites.
Sarcoptic Mange — dips, injections, oral drugs, and spot-on treatments can all be used to treat sarcoptic mange. Determining which option is best depends on a dog’s breed, health, and other considerations, but my favorite treatment is selamectin because of its safety, efficacy, and ease of use. Every dog in the home should be treated to prevent animals from reinfesting each other.
Demodectic Mange — mild cases of localized demodectic mange often resolve without any treatment when a dog’s immune system becomes better able to control mite numbers. Antibiotics, drugs that kill the mites, and medicated dips and ointments can all be prescribed in more severe cases. If an underlying cause of immunosuppression can be identified, it should also be dealt with.
Dr. Jennifer Coates