Mange in dogs

What is mange?

Mange is a skin condition in pets caused by an overpopulation or infestation of parasitic mites. The mites burrow into an animal’s skin (sarcoptic) or over-populate the hair follicles (demodex), causing either itchiness and thickened skin, or skin changes and hair fall. There are different types of mange caused by different species of microscopic mites – the most common being demodectic mange and sarcoptic mange. In this article, we’ll explore the symptoms of mange, how the different types of mange are diagnosed and treated, and whether mange is contagious to humans.

Types of mange

Dogs can get demodectic mange or sarcoptic mange. The type of mange is determined by the type of mite infesting your dog’s skin or hair follicles. Demodectic mange is the most common type, while sarcoptic mange is the more devastating type and is highly contagious to other dogs and even to humans. Left untreated, both demodectic and sarcoptic mange can be fatal.

What causes mange in pets?

Demodectic mange

Demodectic mange is caused by an overpopulation of the skin mite Demodex canis (or other varieties Demodex injai and Demodex cornei). Dogs and humans both have a natural population of demodex mites living in their hair follicles, kept in check by a healthy immune system. If the immune system is compromised (due to illness, complications from a medical condition, or genetics), demodex mites are free to flourish and can cause mange. It’s possible for dogs with chronic conditions like cancer or diabetes to develop mange while their immune systems are weak.

Puppies can sometimes experience demodectic mange, since they acquire the skin mites from their mother. Normal, healthy puppies host demodex with no problems; sometimes experiencing bouts of overpopulation that need a simple topical treatment to bring back under control. However, puppies with a genetically weakened immune system can develop juvenile onset demodectic mange, which is very serious and needs immediate and intensive treatment.

Sarcoptic mange

Sarcoptic mange is caused by an infestation of the skin mite Sarcoptes scabiei. Sarcoptic mange is also referred to as canine scabies, and it occurs when the mite buries itself deep within the skin, causing severe itching and skin changes. Dogs with canine scabies will bite and scratch their skin incessantly, trying to get at the source of the irritation. This causes primary and secondary symptoms, which we will discuss below.

What are the symptoms of mange?

Since the different skin mites take up residence in different parts of the skin, the symptoms of scabies and demodex may differ. Let’s look at both:

Symptoms of demodectic mange

  • hair loss (alopecia) on the face, especially noticeable around the eyes
  • itchiness (though not as severe as with sarcoptic mange)
  • red, scaly skin patches
  • acne-like bumps
  • skin crusting
  • skin thickening and darkening
  • swelling
  • pain and fever if the condition has progressed
  • ear infections

The dog may appear lethargic and have leaky wounds if the demodectic mange is generalised (all over their body and not confined to the face) and has progressed quite far. They will need immediate treatment.

Symptoms of sarcoptic mange

  • intense itching and persistent scratching
  • hair loss as a result of the scratching
  • secondary bacterial and yeast infections
  • red, inflamed skin
  • skin thickening
  • crusting skin

In advanced canine scabies infections, the dog’s lymph nodes will be inflamed and they will become lethargic and malnourished.

How is mange diagnosed?

A veterinarian will do a skin scraping and look at it under a microscope to identify the presence of skin mites or their eggs. The demodex mite is elongated and slightly tapered, while the scabies mite is rounded.

How do you treat mange?

The treatment for both types of mange will depend on how far the infestation has progressed. There are oral medications as well as topical treatments and medical baths, both to kill the mites and promote the healing of the dog’s skin.

The sarcoptes mites may still be in the dog’s bedding and living environment, so it’s important to keep them away from these areas until they’ve been disinfected and bedding has been thoroughly cleaned. Also keep other pets away from the infected dog, to prevent the spread of canine scabies and the animals reinfecting each other.

In the case of demodectic mange, the veterinarian may also identify the systemic illness that’s weakening the dog’s immune system; be it old age, chronic disease or a genetically underdeveloped immunity. They will want to ensure the demodex is kept under control, since a compromised immune system may result in an overpopulation of demodex again in future. If the systemic illness is not being managed, demodectic mange can be fatal. Severe demodectic mange may take a long time to treat, and all dogs respond differently to treatment, but generally the prognosis is good.

Can mange in dogs spread to humans?

We have our own population of skin flora (including demodex mites) to keep our skin microbiome in balance, and cannot be infected with canine demodex mites. Demodectic mange is not contagious to humans or other dogs with healthy immune systems, but sarcoptic mange is a zoonotic disease and highly infectious. What does mange do to humans? Canine scabies mites cannot complete their life cycle in human skin, but people with canine scabies will still experience redness, itching and what appear to be inflamed welts – symptoms that will last until the mites die off. (Be aware that canine scabies is not the same as human scabies, which is caused by Sarcoptes scabiei var. hominis or the human itch mite, and needs immediate treatment to kill the mites as it is highly infectious).

How to prevent mange

Pet owners can prevent demodectic mange by ensuring their dogs are healthy and not suffering from other diseases. Regular vet check-ups give the veterinarian the opportunity to screen your dog and potentially pick up any health conditions that may compromise your dog’s immunity and lead to demodex overpopulation.

You can prevent sarcoptic mange by ensuring your dog is contained within your yard (not exposed to stray animals or unknown environments where a sarcoptes infestation may put them at risk). By keeping your pets away from dogs with known sarcoptic mange, you prevent infection.

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