What Is Mange?
Mange is a broad term used to describe skin disease caused by parasitic mites. In dogs, two forms are most commonly encountered in veterinary practice: sarcoptic mange and demodectic mange. Though both result in skin irritation and hair loss, they are caused by entirely different mite species, have distinct clinical presentations and require different treatment approaches. A third form, cheyletiellosis (sometimes called walking dandruff), is occasionally grouped with mange conditions though it is technically caused by a surface mite.
Getting the diagnosis right matters, because the management of sarcoptic mange differs significantly from that of demodicosis, and misidentification can lead to inappropriate treatment and ongoing suffering for your dog.
Sarcoptic Mange: The Intensely Itchy Form
Sarcoptic mange is caused by Sarcoptes scabiei var. canis, a microscopic mite that burrows into the superficial layers of the skin to lay its eggs. The mite's burrowing and the body's immune response to mite faeces and debris trigger an intense inflammatory reaction. The result is one of the most severely pruritic (itchy) skin conditions seen in dogs.
Signs of Sarcoptic Mange
Dogs with sarcoptic mange typically present with:
- Intense, relentless itching that is often described as out of proportion to the visible lesions
- Hair loss and crusting around the ear margins, elbows, hocks and ventral abdomen
- Thickening and hyperpigmentation of chronically affected skin
- A positive pinnal-pedal reflex — scratching at the ear when the ear margin is rubbed — which is considered a useful clinical indicator, though not definitive
- Rapid spread of lesions if left untreated
Sarcoptic mange is highly contagious — it spreads readily between dogs and can also temporarily infect humans, causing a self-limiting, intensely itchy rash (the mites cannot complete their life cycle on human skin, so the infestation does not persist). Contact with foxes, which are a common reservoir of Sarcoptes in the UK, is a known risk factor.
Diagnosing Sarcoptic Mange
This is where things become frustrating. Skin scrapes — the traditional method of identifying mites — are notoriously unreliable for sarcoptic mange. The mites are present in very low numbers and burrow deeply, meaning they are often not recovered even in genuinely infected animals. It is estimated that mites are found in fewer than 50 per cent of confirmed cases using skin scrapes alone.
Serological testing (blood tests to detect antibodies against Sarcoptes) offers improved sensitivity and is increasingly used in veterinary practice. However, antibodies may not be detectable in the early stages of infection, and false positives can occur. In practice, many vets will treat empirically — that is, treat for sarcoptic mange based on clinical suspicion even without a confirmed mite — especially when the history and presentation are consistent.
Demodectic Mange: A Different Mite, A Different Problem
Demodectic mange (demodicosis) is caused by Demodex canis, a cigar-shaped mite that lives within the hair follicles of dogs. Unlike Sarcoptes, Demodex is a normal inhabitant of canine skin — all healthy dogs carry small numbers of these mites, passed from mother to puppies during nursing. Disease only develops when mite populations expand beyond normal levels, which occurs when the host's immune system is unable to keep numbers in check.
Localised vs Generalised Demodicosis
Demodectic mange can present in two distinct forms, and the distinction has significant implications for treatment and prognosis.
Localised demodicosis typically affects young dogs under 18 months of age, presenting as small, well-defined areas of hair loss and mild scaling, commonly around the face and paws. The itching is minimal or absent. In many cases, localised disease resolves spontaneously as the dog's immune system matures, and treatment may not always be necessary.
Generalised demodicosis involves widespread lesions covering large areas of the body, often with secondary bacterial infection of the hair follicles (furunculosis). This form can be severely debilitating and is almost always associated with an underlying problem with the immune system — whether genetic (in young dogs of susceptible breeds such as Bulldogs, Shar Peis and Pit Bull Terriers) or acquired (in older dogs due to systemic disease, immunosuppressive medication or other stressors). Identifying and addressing any underlying cause is a critical part of managing generalised demodicosis.
Signs of Demodectic Mange
- Patchy hair loss, most commonly on the face, particularly around the eyes and muzzle
- Comedones (blackheads) in affected areas
- Variable itching — generally less severe than sarcoptic mange unless secondary infection is present
- Scaling, redness and skin thickening in more advanced cases
- Pustules and draining tracts if secondary bacterial infection has developed
Diagnosing Demodectic Mange
Unlike sarcoptic mange, demodectic mites are usually straightforward to find. Deep skin scrapes — performed by scraping the skin firmly enough to draw a small amount of blood from hair follicles — typically reveal cigar-shaped mites, eggs and mite debris under the microscope. Hair plucks from affected areas can also be examined. In breeds with particularly thickened skin, such as Shar Peis, biopsy may occasionally be needed if scrapes are non-diagnostic.
Treatment Approaches
Treatment differs substantially between the two forms of mange.
For sarcoptic mange, the isoxazoline class of drugs — which includes fluralaner, sarolaner, afoxolaner and lotilaner — has become the standard of care in recent years. These are the same active ingredients found in many modern flea and tick preventatives. They are highly effective against Sarcoptes mites and are generally well tolerated. Traditional treatments such as selamectin spot-ons and doramectin injections remain effective alternatives. All in-contact dogs should be treated simultaneously, and the environment should be vacuumed and bedding washed.
For demodectic mange, isoxazolines are also now considered first-line treatment, having largely replaced older protocols involving amitraz dips (which carry handling risks) or prolonged courses of oral milbemycin or ivermectin. Localised cases in young dogs may resolve without treatment, but monitoring is important to ensure progression to the generalised form does not go unnoticed.
When to See Your Vet
Any dog showing significant hair loss, persistent itching or skin lesions should be seen by a vet promptly. Both forms of mange are diagnosable and treatable, but the sooner treatment begins, the better the outcome — particularly in cases of sarcoptic mange, where rapid spread and severe discomfort can significantly affect quality of life. If you have other dogs in the household or have been in contact with foxes, mention this to your vet as it will inform their approach to diagnosis and treatment.