Author: Tracy Reis, DVM
There are two types of mange that can affect dogs, demodectic mange and sarcoptic mange. Both forms are caused by parasitic mites that inhabit skin and hair follicles, but they are from different species. Some of the first signs of mange are itchiness and possibly hair loss. The parasite spends its entire life on the dog. It is believed that most dogs have some demodectic mites on their skin without actually developing demodex. Most likely, puppies acquire small numbers of mites while nursing and snuggling with their mothers.
Juvenile mange is usually self-limiting; in other words, as a healthy dog ages and its immune system is fully functioning, it keeps the mites at a very low number that does not cause clinical signs of disease. However, there are certain breeds and dogs in general where a large number of mites will develop, causing signs.
There are two forms of demodectic mange (demodex) – localized and generalized. The localized form is seen in young dogs and presents as a small patch of alopecia (hair loss) on the face, ears, trunk or legs. These patches are rarely inflamed or itchy, and close to 90% of them will resolve in two months with no treatment.
The generalized form is usually seen in adult dogs and presents several areas of hair loss and itchiness. If they are itchy, they probably have a secondary skin infection that will need treating as well. They may also have areas of skin that are thickened and hyperpigmented (darkened). Sometimes their remaining coat will be greasy, and they may have a musty smell. The ears may also have excessive wax. Other times, they will have enlarged lymph nodes, a low grade fever, and be listless or just seem “not themselves”. Occasionally, older dogs with no previous history of mange may show symptoms of the generalized form. These dogs will often have a suppressed immune system, and possibly some other underlying disease, and further diagnostics should be done such as a bloodwork and a urinalysis. Certain breeds including Shar Peis, Bulldogs, and other wrinkly breeds can suffer from lesions only on their feet. The feet will be red, swollen and smelly. This form can be very resistant to treatment.
The second type of mange is sarcoptic mange known more commonly as scabies. This form is both highly contagious between dogs, and zoonotic (humans can catch it from contact with their dog). Sarcoptes is usually found in younger dogs that are placed in crowded situations and dirty living conditions, such as shelters, unclean boarding facilities, and even groomers' offices. It can also be spread via fomites (blankets, toys, etc).
Because these mites burrow into the skin where the hair is thinner, there may be small red bumps. These dogs are extremely itchy, and white scales may occur where they have scratched. These crusts are usually seen along the edge of the dog’s ears. It is the most intensely itchy chronic disease. These dogs can also develop secondary skin infections, and occasionally systemic infections.
Doing a skin scraping and looking for mites on a slide under a microscope can usually diagnose both forms of mange. Of the two mites, demodex mites are easy to find and hard to treat, while scabies can be hard to find but easy to treat.
Some natural treatments include garlic and wormwood for their natural parasitic repellent effect. Neem and lemongrass are also natural anti-parasitics, and are soothing for irritated skin. Always consult your veterinarian before treating your pet yourself.