Mange is the infestation of your dog's skin by tiny mites that usually results in hair loss and itching. Not all mites affecting dogs behave in the same way, with individual species of mite boasting their own unique ill effects on their poor victims.
What are the types of mange mite that affect dogs?
The two main types of mange mite that can affect dogs are sarcoptic and demodectic, with others like ear mites and seasonal harvest mites usually causing less severe and more superficial problems.
Scabies (sarcoptic mange)
Sarcoptic mange - otherwise known as 'scabies' - is caused by a highly contagious mite (Sarcoptic scabei) that spends its whole life cycle burrowed within the outer layers of your dog's skin and causes a typical intense itching. This quickly leads to raw, painful lesions caused by self-inflicted scratching and chewing, especially at the ear flaps and elbows.
How is scabies transmitted?
Scabies can be passed from dogs to their unwitting owners through direct contact, or by contaminated grooming products and infected bedding. Foxes are a common source of sarcoptic mange too, with recent rises in urban fox populations being blamed for particularly nasty outbreaks.
Demodex (demodectic mange)
Unlike scabies, demodectic mange, or 'demodex' as it can be known, behaves very differently, with individual mites (most commonly Demodex canis) living within the actual hair follicles of your dog, and very rarely spreading to us or other dogs. In fact the only real way it can be passed on is during the first few days of life from mother to pup via the muzzle.
Which dogs are at risk of demodex?
Dogs with healthy immune systems rarely succumb to full-blown demodex, as they are able to contain the parasite quickly and efficiently, stopping it in its tracks from multiplying and spreading disease. However, a small number of dogs with much weaker body defence systems aren't able to overcome these mites, so lesions often develop. The resulting disease spreads locally to the face and forelimbs, or more commonly across the dog's whole body, turning affected skin a blue/grey colour due to the presence of thousands of blackheads or 'comedones'.
Is demodex serious?
Cases of demodex are usually resolved when the puppy's immune system kicks in at about a year old. But without sufficient immune control, and depending on which of the three species of demodex is present, the disease can quickly become very generalised, even life threatening, with hair loss, skin reddening, and severe secondary bacterial and fungal infections.
Most dog owners will have come across an infestation of ear mites (Otodectes cyanosis) at some point. This is a disease that is more commonly found in cats, but it can also affect dogs. So if you suspect your dog has an ear infection make sure you always mention that your dog has a feline friend, as they may also need treatment to avoid re-infestation. Ear mites are easily one of the major causes of ear canker (Otitis externa), which can affect all breeds of dog. They differ from their burrowing relatives by being just visible to the naked eye as very tiny moving white dots. Treatment is usually quite straightforward with regular ear cleaning followed by topical, anti-parasitic ear drops.
Harvest mites, or 'chiggers', are six-legged larvae (Trombicula autumnalis) frequently picked up by dogs exercised in more rural areas, especially those with chalky soil. This larval mite can also affect cats and humans, with textbook signs in your dog of severe itching (pruritis) of the feet. Harvest mites can be seen with the naked eye as tiny bright orange or red dots especially between the toes and lower legs.
How serious are harvest mites?
Fortunately they aren't as serious as scabies or demodex, either; however, accurate diagnosis is always necessary with early treatment to avoid self-mutilation and secondary infection from the dog scratching the affected area.
Our final type of mite affecting dogs is very descriptively known by the term 'walking dandruff' or 'cheyletiellosis'. Another relatively common canine mite (usually Cheyletiella yasguri), its whole life cycle is spent on the dog's skin surface within the scales and debris, and it can spread between dogs and other animals.
Signs of cheyletiellosis
Unlike most other mite-related conditions, cheyletiellosis results in virtually no itching at all; instead most owners complain about their dog's excessive dandruff or 'scurf'. Cases seen are usually in puppies from poor backgrounds (e.g. puppy farms), but there's also a form (Cheyletiella parasitivorax) that can be caught from infected rabbits.
How is cheyletiellosis diagnosed?
Diagnosis is relatively straightforward and involves examination of surface scales with a piece of sellotape, and observing adult mites actually walking through the scales of skin - like a form of walking dandruff!
How are mite infections treated?
Usually a few anti-parasitic washes and environmental decontamination prove curative. Most mite infestations affecting dogs can be diagnosed by direct identification under the microscope after skin scrapes or hair plucks. Unfortunately these don't always reveal the offending creatures, so your vet may start treatment before any positive identification. These days with effective new drugs, anti-parasitic shampoos, dips and spot-ons, it usually means a much quicker response time but occasionally multiple treatments taking up to six months are necessary.
This article was written by Marc Abraham, a vet based in Brighton who regularly appears on UK television.
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