Mites (Demodectic or Follicular Mange)
Demodectic mange, also known as follicular mange, or red mange, is caused by the hair follicle mite Demodex canis, which is found normally in most dogs. Infestation leading to mange develops in dogs without natural immunity to the mite. Demodectic mange is not contagious.
Demodectic mange usually affects young dogs (less than 2 years of age) with immature immune systems and older dogs with weakened immune systems.
Demodectic mange causes hair loss (alopecia) that can be localized, usually on the head or legs, or over the entire body. The areas of hair loss appear scaly, red, and crusty. Secondary bacterial infections in the hair follicles are common, leading to inflammation, and reddened skin (thus the term "red mange").
The prognosis is age dependent. It may resolve without medical intervention in young dogs (less than 1 year old). Eighty percent to 90% of young dogs recover. The prognosis is more guarded for older dogs and is generally better if the underlying cause of the dog's immunosuppression (e.g., liver disorder, malnutrition, diabetes) can be diagnosed and treated.
Demodectic Mange Treatment
Amitraz dips had been the therapy of choice; however, this product is no longer available commercially. Due to this change, avermectins are becoming the first choice treatment, although they are not labeled for this use.
Daily ivermectin therapy may be administered. Ivermectin is not recommended for collies, other herding breeds, dogs with heartworm, or puppies under 6 months of age.
Milbemycin oxime therapy may be administered daily, until 1 month after the disappearance of mites (based on skin scrapings). This treatment can be expensive, especially for large dogs.
In problematic cases, immuno-modulating drugs may be used to treat the underlying immunosuppression.