Not All Mange Is the Same — and the Distinction Matters Enormously
Mange is one of those words that causes immediate alarm in dog owners, and understandably so. Hair loss, thickened skin, and relentless scratching are distressing to witness. But mange is not a single disease — it is a term applied to two entirely different parasitic skin conditions caused by two completely different mites, with different causes, different risk levels, and very different implications for treatment. Knowing which type you are dealing with changes everything.
The Two Types of Mange Explained
Demodectic Mange (Demodex canis)
Demodex mites are a normal part of a dog's skin flora. Virtually every dog carries a small population of these microscopic mites in their hair follicles, passed from mother to puppy in the first days of life. In dogs with a healthy immune system, Demodex populations remain controlled and cause no harm. Problems arise when the immune system — for any reason — fails to keep mite numbers in check, allowing the population to explode and cause disease.
Demodectic mange is therefore not contagious in the traditional sense. It is not passed between adult dogs through normal contact.
Sarcoptic Mange (Sarcoptes scabiei)
Sarcoptic mange, also known as canine scabies, is caused by a burrowing mite that is not part of normal skin flora. This mite is highly contagious and spreads readily through direct contact between animals — and can also be transmitted to humans, where it causes a temporary, intensely itchy rash.
Unlike Demodex, Sarcoptes can be acquired by any dog regardless of immune status. It spreads rapidly in environments where dogs are in close contact, such as kennels, rescue centres, and dog parks.
Symptoms: How to Tell Them Apart
Demodectic Mange
- Localised patches of hair loss, often starting around the face, eyes, and forelimbs
- Skin may appear red, scaly, or thickened in affected areas
- Less intense itching than sarcoptic mange in many cases, particularly in localised disease
- Generalised disease (involving large areas or the whole body) is more severe and often accompanied by secondary bacterial infection, leading to pustules and crusting
Sarcoptic Mange
- Intense, relentless itching — often described as the most severely pruritic of all parasitic skin conditions
- Hair loss and red, crusty lesions typically beginning on the ear margins, elbows, hocks, and belly
- Lesions spread rapidly if untreated
- The dog may be in visible distress and unable to rest comfortably
- Other animals in the household often develop similar signs
A dog that is excessively itchy, or whose housemates are also developing skin problems, should be seen by a vet without delay. The ear margin scratch reflex — where scratching the edge of the ear causes the dog to involuntarily scratch its leg — is a classic clinical indicator of sarcoptic mange.
Diagnosis
Both types of mange are diagnosed by a vet, typically through skin scrapes examined under a microscope. Demodex mites are usually straightforward to find on a deep skin scrape. Sarcoptes is notoriously difficult to identify microscopically — the mites are present in low numbers and are missed in the majority of scrapes even in confirmed cases. For this reason, a diagnosis of sarcoptic mange is often made on the basis of clinical signs, history, and response to treatment rather than confirmed microscopy alone.
Blood tests and skin biopsies may be used in complicated or unclear cases.
Treatment
Treating Demodectic Mange
Localised demodectic mange in young dogs often resolves on its own as the immune system matures. Generalised disease requires treatment with prescription antiparasitic medications, typically isoxazoline-class drugs (such as those commonly used for flea and tick prevention), which have proven highly effective against Demodex. Treatment may continue for several months, with regular monitoring of skin scrapes to confirm mite clearance. Underlying causes of immune suppression — such as hormonal disease or concurrent illness — should also be investigated and addressed.
Treating Sarcoptic Mange
Sarcoptic mange responds well to the same isoxazoline class of drugs, as well as to selamectin and other prescription antiparasitic treatments. All in-contact animals must be treated simultaneously. The environment should be cleaned thoroughly, as Sarcoptes mites can survive off the host for up to three days, allowing reinfection from bedding, furniture, and grooming equipment.
In households where a human family member develops an unexplained itchy rash while a dog is being treated for sarcoptic mange, a GP appointment is advisable.
Practical Summary
- Demodectic mange reflects immune imbalance; sarcoptic mange is a contagious infestation
- Intense itching in multiple animals strongly suggests sarcoptic mange
- Both types require veterinary diagnosis and prescription treatment
- Modern isoxazoline treatments are effective against both mite species
- For sarcoptic mange, treat all in-contact animals and decontaminate the environment
- For demodectic mange, investigate any underlying health condition contributing to immune suppression
- Do not attempt to treat mange with over-the-counter products — consult your vet for an accurate diagnosis first