Mange in Dogs, Cats and other pets

Ron Hines DVM PhD 2/9/03
Mange is a rather common disease in household pets. Dogs are primarily susceptible to two forms of mange, Demodectic mange (red mange) and Sarcoptic mange. Demodectic mange is generally seen in dogs less than two years of age. These mange mites are passed to puppies skin from their mothers.

Demodectic mange mites live in the hair and oil (sebaceous) follicles of the skin. The first signs of this disease are patchy areas of hair loss about the head and forelegs, which do not itch and do not appear inflamed. These areas may spontaneously resolve or become larger until large areas of the pet’s skin is involved.

It is considerably rarer in cats. A few of these parasites are present in the skin of many or all normal dogs. However dogs which develop disease have a defect in their immune system (T-cell defect) and can not keep the number of mites under control.

The only product approved for use on Demodectic mange in the United States is amitraz (Mitaban). This concentrated liquid is diluted to a dip and the entire animal is immersed and scrubbed in the solution every two weeks until no living parasites can be seen under a microscope.

A compound named benzyl benzoate cream was once used to treat small areas of infection. It is no longer believed to be effective. I will sometimes mix a 10% solution of Amitraz in propylene glycol and have the owner first cleanse and then massage this solution into isolated lesions.

I have had good success in curing small areas of Demodectic mange in this way. The effectiveness of treatment is hard to evaluate because small lesions often go away on their own. Shar Pei dogs are notorious for their susceptibility to Demodectic mange.

When amitraz (Mitaban) dips fail to halt the infection, I have had good success in placing these dogs on daily oral ivermectin. This product is sold as Ivomec 1% and the dose I use is 1ml (cc or approximately 15-20 drops) per110 lbs body weight.

This comes out to 200 mcg/kg of body weight. Ivermectin may take up to a year to completely cure the dog. In severe cases, secondary bacterial skin infection is severe and subcutaneous lymph nodes enlarge with mites present in these nodes.

The second common form of mange in dogs, other pets (and wild animals) is Sarcoptic mange. This microscopic spider-like mite burrows through the layers of the skin causing an intense itch and streaks of reddened skin.

After a month or so the skin becomes very crusty. It is spread from one mature dog to another by contact or by contact with objects the infected dog has touched. Humans in contact with these pets will often begin to itch too.

This disease in man was once called the seven year itch. It is the disease that back-woods folk and farmers used to cure by rubbing the dog with burnt motor oil. Do not attempt this ! The most gentle way of curing this disease (but the most smelly way) in all species of animals is with lime sulphur dips.

Oral or injectable ivermectin cures the disease very well too. However, Ivermectin can be toxic in cats. Besides dogs, I see this disease in cats, hedgehogs raccoons and squirrels.

A third form of mange, psoroptic mange, I see most often in rabbit ears and the area surrounding the ears. All ear-mite medicines cure this disease but the ears often need a soothing antibiotic corticosteroids cream for a week or two to heal.

A form of mange that I see in budgerigars (parakeets) and canaries is knemidocoptic mange. It affects their legs, the base of the beak and their vents.

The skin in these areas is thickened and flaky. It responds very well to ivermectin or oily topical products containing rotenone (derris root & cube resin) such as Goodwinol. Goodwinol is difficult to obtain these days, but the active ingredient, rotenone, can be purchased as an organic rose and vegetable insecticide and mixed with margarine.

The reason most mange can be treated with any non-toxic oily product is that mange mites, being arachnids, breath through openings (sphericals) along their body. Any substance which plugs up these pores kills the mites. The exception are Demodectic mites which live so deeply within hair follicles that oily substances do not seem to affect them.

I write these articles in a single pass, from memory and personal experience. So please excuse omissions I may have made or typographical errors. If I have neglected to mention something you feel is important, please ask me through second.chance2@verizon.net. If you need products to deal with these conditions please also contact me through that address.