Mange – A Skin Disease Affecting Cats and Dogs
Posted on February 9th, 2012 in Pet Health Issues | No Comments »
Mange is a skin condition in dogs and cats that is caused by a parasite known as a mite. There are typically two types of mites that are the cause – demodex or sarcoptes (more commonly known as scabies).
Demodex mites cause demodectic mange, which is more common in dogs than in cats. Demodex mites live on the skin of healthy animals and are not infectious to humans or other animals. Typically, the animal’s immune system prevents these mites from causing a problem. However, in young animals whose immune system is not fully developed, or in older animals that have another illness that is causing their immune system to be weak – the mites are able to overcome the weakened immune system and an infection results.
Demodectic mange can be localized to one or a few spots, or can be generalized over the entire body. The main clinical sign is hair loss (patches or generalized) and yet the dog is often not itchy. However, a secondary bacterial infection can occur as well, causing redness and scaling or scabs, and this will result in itchiness. Lesions usually first occur on the head, chest, and front legs, and then gradually spread over the rest of the body.
Demodex is diagnosed through a skin scraping performed by your veterinarian. The skin scraping is then examined under the microscope for the presence of the mites. Treatment is with a medication called Ivermectin and usually lasts for weeks (6-8 weeks, sometimes longer), depending on the severity. Any secondary bacterial infections are treated with antibiotics.
Sarcoptes mites, or scabies, cause sarcoptic mange. This is a highly contagious infection that can affect dogs and cats, as well as humans. In contrast to demodex, scabies is extremely itchy. The lesions tend to be more severe than demodex and occur first along the margins of the ears, around the eyes, elbows, or chest, but can also spread over the entire body. The lesions involve hair loss, pustules, redness, and scaling.
Like demodex, scabies can also be diagnosed by a skin scraping. However, the mites tend to be hard to find and a negative skin scraping does not rule out sarcoptic mange. A presumptive diagnosis is typically based on clinical signs, especially on the severity of the itchiness. Treatment is with a topical medication called Revolution. Revolution is more generally known as a flea preventative and is used once a month when dealing with fleas. When treating scabies, the medication is instead given more frequently, often every 2 weeks, for a total of at least 3 doses.
Mange can be a frustrating condition to manage and treatment is often a long process. It is important to contact your veterinarian when any skin issue is first noticed. Prognosis is dependent on the severity of the illness and the presence of any other underlying conditions.