Overview

Demodectic mange, also called “red mange,” is a skin condition caused by the mite species Demodex canix. Almost all dogs naturally carry this mite, since it is transmitted from the mother to the nursing pups during the first few days after the pups are born. Normally mites do not present any problems; however, in some situations when a dog’s natural defence system becomes impaired, the mite population can explode and cause serious skin irritation, hair loss, and other secondary infections. Sometimes demodectic mange is a result of other underlying conditions that have weakened the dog’s immune system, such as immune diseases, cancer, or intense external stress such as starvation.

The mites responsible for demodectic mange are only transmitted from mother to pups; therefore, demodectic mange is not contagious among dogs, and cannot affect humans. Some breeds are more susceptible to mild demodectic mange at a young age, leading to the speculation of a hereditary component in this disease.

Symptoms and Diagnosis

Localized demodectic mange usually presents red, scaly lesions that are most frequently found on the dog’s face and forelegs. These small bold spots generally disappear by themselves. In more serious cases, often accompanied by swollen lymph nodes, the localized lesions will enlarge and develop into generalized demodectic mange where there are large patches of bald, scaly skin and skin infections. In juveniles under one year of age, this condition may again disappear spontaneously without much intervention. However, in older dogs generalized demodectic mange is usually a sign of serious underlying health issues.

Skin scrapings are usually performed, and observed under a microscope to positively identify the mites. A similar disease, called sarcoptic mange, is caused by a different species of mite and requires different treatment.

Treatment

Most mild cases will improve by themselves over time, especially in puppies; however, treatment is still recommended to facilitate a speedy recovery. Small, localized lesions can be controlled with ointments or medicated shampoos, and will generally improve within weeks. In more seriously affected dogs, especially if secondary infections are present, oral medications and antibiotics are needed in addition to the topical treatments. Both the medicated shampoo/bath treatment and oral medication have some limitations: the medicated bath cannot be used in toy breeds or very young puppies, and the oral anti-parasite medication cannot be used in most herding breeds.

Some home remedies involve bathing the infected dog in various household substances such as motor oil; this is harmful to the dog and is NOT a viable treatment of demodectic mange.

It is possible for demodectic mange to relapse, although most frequently this is a result of incomplete treatment. With most healthy and young dogs, demodectic mange is easily controlled and treated. The older the dog, the more difficult to completely cure demodectic mange, and sometimes it is necessary to find and remove the underlying health problems. Spaying or neutering is sometimes recommended since reproductive functions like breeding and heat cycles are additional physiological stresses that can trigger a relapse.