There are two different manges that affect dogs. These are sarcoptic mange or scabies and demodectic mange, often known just as demodex.
Both diseases are caused by mites, tiny eight legged organisms that burrow into and live in the layers of the skin.
This is also known as scabies, its common name for the infestation in humans to whom it is transmissible from dogs. The disease in dogs is sometimes called `red fox mange’ or `wombat mange’. Both of course being derived from the source of the infestation. Transfer of the condition is by direct contact between animals or from picking up larvae (nymphs) or adult females from tracks where these have dropped off affected foxes or wombats.
The earliest signs of infection are areas of redness and itchiness on the muzzle, face, the inner surfaces of the lower legs. These areas are seldom those that fleas attack first, so the condition should not confused with flea eczema, but it may easily be confused with tinea.
The mites burrow under the skin and travel just beneath the surface causing intense itching. This itching causes the affected animal to damage his coat and skin. This allows a secondary bacterial infection, and sometimes more seriously a fungal infection, to occur. This causes much more skin damage and increases the difficulty of treatment and repair of the skin.
The condition is diagnosed accurately by the taking of skin scrapings from the edges of the affected areas. The presence of mites, their eggs and their nymphs is diagnostic. It may be necessary to take several scrapings to prove the diagnosis.
Treatment is washing in flea preparation at weekly intervals.
Secondary infections may need to have additional treatment. The immediate environment should also be sprayed with insecticides to kill any mites or nymphs that have fallen off the affected animal.
The use of corticosteroids is contraindicated to control the itching, as the parasites may increase dramatically within the skin, causing further problems.
The disease after disappearing from urban and suburban regions for many years, because of the invasion of these areas by foxes, there is an increasing number of infestations, not always recognized as sarcoptic mange. Sometimes a correct diagnosis is not achieved until the owner has also become infected. In humans the commonest site of the infection is on the inside of the lower arms, where the intensely itchy red lines are almost self explanatory.
Sarcoptic mange is a nuisance disease, it is easily diagnosed. It is easily treated, the biggest problem is growing a decent coat on the dog again. Once the condition is removed, new coat will immediately grow through where the areas were affected, but this will appear mottled against the coat that was undamaged, so that really the coat does appear normal until the next major moult.
This is a much more serious disease. It is difficult to treat successfully and the secondary bacterial infections, often staphylococcus, are very debilitating on the general health of the affected animal. This mite lives its entire life cycle deep within the host’s skin, right down with the oil glands of the skin. It is not easily transmitted from dog to dog, except by direct and constant contact. It is unlikely to infect man.
The condition is diagnosed by finding the mites or their nymphs in deep skin scrapings.
It is easily differentiated from sarcoptic mange because it does not cause itching. There are two forms of the disease, known as squamous and pustular.
In the squamous form, there is hair loss around the eyes, or muzzle, hocks, elbows, feet and neck. There is usually a scaly skin with a light grey greasy feel. The condition may remain at this stage for a number of years. If the animal is stressed, the condition will worsen – the hair loss will become generalized, the skin will thicken and the greasiness will increase.
In the pustular form, the skin is thickened, wrinkled and inflamed. Pustules are present; these may become abscesses, or pus may underrun the skin. There may be irritation when this occurs. There is nearly always bacterial invasion in this form of the disease.
Demodex may be treated with oral flea preventatives, used at the rate for flea control. These preparations should not be used on young puppies except under strict veterinary supervision. These drugs often take many weeks to express the damage they may cause the central nervous system, which may appear from any signs of vitamin deficiencies to wobblers disease and even skeletal abnormalities.
If the disease is the pustular form, concurrent treatment with antibiotics to which the secondary infections are susceptible are essential.
Demodectic mange treatment is also helped by increasing the general health of the dog with food supplements such as cod liver oil, yeast, kelp, vitamin C and ensuring that the diet is rich in digestible protein, and has some simple carbohydrates in it. Increasing the dog’s general health will help towards healing the affected areas and improve the resistance to reinfection or to building up of a residual infection not removed with the initial treatment.
Bitches that have demodectic mange, or those that have never coated up completely after treatment for demodectic mange should not be used for breeding. Puppies develop demodectic mange in the nest through constant contact with their mother, if she is infected.
Demodectic mange is commonest in short coated dogs. This is because of the nature of the mite. It would more likely be brushed off the fur of a longer coated dog before it could enter the skin. But still it may occur in longer coated breeds, and these are even more likely to infect their puppies, because all puppies are born with relatively short coats.
It is irresponsible of owners of dogs with demodectic mange to take their dogs into public areas where there are other dogs in close proximity. Certainly such dogs should never be taken to functions catering for dogs where there is close contact.=