Demodectic Mange (sometimes called "Red Mange") is caused by tiny mites that live on every animal's body (humans included). Puppies are not born with this parasite but within hours of birth this mite transfers itself from mother to pup. All dogs have the mite which is usually never a problem.
However, in some dogs, certain stresses can cause a breakdown in the immune system which then allows the mite population to multiply uncontrolled. Stress can be either physical or mental. Such conditions as neglect, underfeeding, traveling, teething, sexual maturity can cause actual physical changes that unbalance the dog's body system. The mite population explosion is actually a symptom of the immune system malfunction rather than being the true root of the problem.
When the population of mites explodes hair folicles become affected. The result is balding (excessive shedding of hair). In turn the skin becomes irritated by infections causing a red rash (hence the name Red Mange) to appear. Sometimes this occurs on only certain sections of the dog (localized), while other times it appears all over the body (generalized). A vet needs to be consulted in the case of generalized DM. The fatality potential lies in untreated symptoms which can lead to septic infections which can lead to deteriorating health, and then death.
Some vets recommend dipping in solutions such as Mitaban for localized Demodetic Mange to get rid of these critters. The problem with dipping is that the underlying problem is not addressed and the dog's immune system is not given a chance to recover. Some dogs are very sensitive and cannot handle the dipping. Italian Greyhounds tend to be a very sensitive breed, so I do not recommend dipping. I treat with a supportive approach to the localized form of demodex: peroxide shampoos, topical treatments, diet, and antibiotics. In this way the dog's body is given the opportunity to combat these mites. While this method takes longer to get rid of the mites, my success rate as been high (so far all dogs treated for localized DM have had it disappear). Also, these same dogs have not had a reappearance of DM!
Generalized DM is a whole other ball game! It is important to remember that in generalized DM, the number of mites is so high that treating in the manner that I recommend for localized would not give the dog a chance to recover. In other words the immune system is overloaded with fighting mites and can't combat it. Either dipping in Mitaban or (for the extra sensitive breeds) applying Mitaban directly to the infected areas would be the best alternative. When dipping, it should be understood that the dog's immune system is already dysfunctional and the condition is serious. I do recommend in generalized DM that dogs should be spayed or neutured as the immune system does have a problem which may pass on to future generations.
As always, consulting with a veterinarian is crucial. If severe or left untreated, DM can develop into a serious health threat to an animal. It is nothing to fool around with!