Health & Medical

Most people picture mange as something that happens to neglected dogs living rough, a disease of dirt and bad owners. That belief is wrong often enough to demolish straight away. Pampered, well-fed, thoroughly loved dogs get mange. Show dogs get mange. And the word itself is close to useless alone, because it covers two conditions caused by two unrelated mites that differ in how they spread, how they look, whether they itch, whether you can catch them, and what happens next. Getting the distinction right is the whole job.

Sarcoptic mange, which itches like nothing else

Sarcoptic mange, also called canine scabies, comes from a mite that burrows into the surface layers of the skin. The itch it produces is on another scale altogether. This is not a dog who scratches a bit in the evenings; this is a dog who cannot settle, who wakes you at night, who chews at himself while you are talking to him, who has scratched raw patches into skin that looked fine a fortnight ago. Owners often describe it as the dog having gone mad rather than having a skin problem.

The distribution is a strong clue. Sarcoptes favours sparsely haired skin: the outer margins of the ear flaps, the points of the elbows, the hocks, the chest and belly. Ear margins in particular develop crusty, scabby edges that flake under your thumbnail. Vets often test the pinnal-pedal reflex, rubbing the ear tip and watching whether the dog's hind leg starts scratching at thin air. Crude, and not proof, but a strong positive raises suspicion sharply.

Two other features matter enormously. First, it is genuinely contagious, passing readily between dogs in close contact and travelling on bedding and grooming kit. Foxes are a well-recognised reservoir, so a dog who walks where foxes lie up has a plausible route of infection with no other dog involved. Second, humans can catch it. Our skin is the wrong host, so the mites cannot complete their life cycle on us, but they burrow far enough to cause an intensely itchy red rash on the forearms, waist and abdomen where the dog leans against you. It clears once the dog is treated, but if people in the house have mysteriously started itching too, mention it.

Diagnosis is where this one becomes frustrating. Skin scrapings under the microscope are the traditional test, but the mites hide in small numbers and a scrape frequently comes back clean on a dog who definitely has scabies. A negative scrape does not clear the dog. Blood tests help, though they miss early cases before antibodies build. So a treatment trial is standard practice rather than a sign of guessing: if the picture fits, your vet treats and watches, and dramatic improvement within a couple of weeks is the answer.

Demodex, the mite that already lives on your dog

Demodex is a different animal in every sense. These mites are normal residents of canine hair follicles, present on almost every healthy dog, passed from the mother to her puppies in the first days of nursing. They cause no trouble until something lets them multiply beyond what the skin can hold. Demodicosis is therefore not really contagious and not something your dog caught at the park. It is an overgrowth, and the interesting question is always why.

The classic itch is missing, which surprises people. A dog with uncomplicated demodicosis is usually not especially itchy. You see hair loss instead, often in neat patches around the eyes, on the muzzle and the front legs, with skin that may look thinned, greyish or scaly. If the dog is scratching hard, a secondary bacterial infection has usually moved into the damaged follicles, and that needs treating alongside the mites.

Age at onset changes the meaning completely. In a puppy, localised demodicosis with one or two bald patches reflects an immune system that has not finished maturing, and a good proportion resolve on their own with monitoring alone. In an adult with no previous history, generalised demodicosis is a red flag that sends your vet hunting for a reason. Cushing's disease, an underactive thyroid, cancer, chemotherapy and long-term steroid or immune-suppressing medication are all worth ruling out, because treating mites while ignoring the cause underneath is a short-lived victory. Diagnosis is straightforward: a deep skin scrape, squeezing to push mites out of the follicles, or plucked hairs under the microscope.

Treatment got dramatically better, and the internet did not notice

Anyone whose memory of mange treatment involves weekly dips in a foul-smelling solution, gloves, masks and a dog who trembled at the bucket is remembering accurately. That era is largely over. The isoxazoline parasiticides, the same oral and spot-on products many owners already use for fleas and ticks, turned out to be highly effective against both Sarcoptes and Demodex. For most dogs treatment is now a tablet or a pipette and a follow-up scrape. High-dose ivermectin protocols, dangerous for herding breeds with the MDR1 mutation, have largely been retired in favour of safer options. Your vet chooses product, dose and duration, and repeat scrapes decide when to stop, not the look of the coat.

What has not improved is the quality of advice circulating online, so a blunt warning. Do not put used motor oil on your dog. It turns up in home-remedy folklore with depressing regularity, it does not reliably kill mites, and it causes chemical burns and poisoning when the dog licks it off. Undiluted tea tree oil is the other one, toxic to dogs and worse in cats. Bleach dilutions and kerosene belong in the same bin. They wreck an already inflamed skin barrier and delay the one thing that works, which is a proper diagnosis and a licensed treatment.

If your dog is losing hair, crusting at the ear edges or scratching in a way that has changed in character, go and get scrapes done. Both of these conditions have good outcomes when they are correctly named. Neither improves while it is being guessed at.