Mange on a dog typically starts with patchy hair loss, red or inflamed skin, and intense scratching. The exact appearance depends on which type of mite is involved, but the two most common forms, sarcoptic mange and demodectic mange, look noticeably different from each other and show up in different places on the body.
The Two Main Types of Mange
Sarcoptic mange (also called scabies) is caused by a burrowing mite that triggers a severe allergic reaction to both the mite itself and its feces. The hallmark sign is extreme itchiness, often sudden in onset. You’ll notice your dog scratching, biting, or rubbing against furniture relentlessly. The skin along the ear margins, elbows, and hocks (ankles) is usually affected first. These areas develop crusty, yellowish scabs, redness, and hair loss. Because the dog scratches so aggressively, the skin can quickly become raw and broken.
Demodectic mange looks quite different. It’s caused by a mite that lives in hair follicles and is typically not very itchy in its early stages. In puppies under six months old, it often appears as mild, patchy bald spots on the head or limbs. These patches may look slightly pink or scaly but aren’t usually painful or irritated. Many cases of localized demodectic mange in puppies resolve on their own without treatment.
Localized vs. Generalized Hair Loss
The distinction between localized and generalized demodectic mange matters because the two look dramatically different. Localized demodicosis involves a few small, well-defined bald patches, usually no more than a couple of centimeters across. The skin in those patches may appear slightly darker or flaky, but the dog generally acts normal otherwise.
Generalized demodicosis is a much more serious condition. Multiple large areas of hair loss spread across the body, and those bald patches often merge together into broad regions of exposed skin. The skin turns red, thickens, and frequently develops secondary bacterial infections. At this stage, the dog may have pustules, open sores, and a noticeable odor from infected skin. Generalized demodicosis can affect the feet as well, causing swelling between the toes, which is sometimes the only visible sign in certain dogs.
Early Warning Signs Before Major Hair Loss
With sarcoptic mange, the first thing you’ll likely notice is the scratching, not the skin changes. A dog with scabies scratches with an urgency that’s different from normal itching. If you rub the edge of your dog’s ear and the hind leg on that side kicks reflexively (called the pinnal-pedal reflex), that’s a strong clue. Within days, the ear tips may develop crusty edges, and small red bumps appear on the belly or elbows.
Demodectic mange is sneakier in its early stages. You might spot a single bald patch around the eye, on the muzzle, or on a front leg. The skin there looks smooth or slightly scaly but not obviously irritated. Because the dog isn’t scratching much, these early patches are easy to miss or mistake for a scrape or minor skin irritation.
What Infected Skin Looks Like
When mange goes untreated, secondary bacterial infections are common with both types. The skin takes on a greasy or waxy texture and may feel hot to the touch. Pustules (small pus-filled bumps) can develop, especially in generalized demodicosis where mites have damaged hair follicles enough for bacteria to move in. Deep skin infections cause the skin to swell, crack, and ooze. The smell is distinctive: a musty, sour odor that doesn’t go away with bathing.
In advanced sarcoptic mange, the constant scratching leads to thickened, leathery skin, particularly on the elbows and ear flaps. The skin may darken in color, a change called hyperpigmentation. Dogs with severe, widespread mange can lose hair over most of their body, and the combination of crusting, thickened skin, and hair loss gives them a rough, almost elephant-like appearance.
Breeds With Higher Risk
Demodectic mange has a genetic component. Certain breeds are significantly more likely to develop it. For juvenile-onset demodicosis (appearing in puppies), British Bulldogs, Staffordshire Bull Terriers, Chinese Shar-Peis, Dogues de Bordeaux, Pugs, French Bulldogs, and Boxers all show increased risk compared to mixed-breed dogs. For adult-onset demodicosis, Chinese Shar-Peis, Shih Tzus, West Highland White Terriers, Pugs, Boxers, and Border Terriers face elevated odds. Three breeds, the Chinese Shar-Pei, Pug, and Boxer, show up on both lists, making them particularly predisposed regardless of age.
If you own one of these breeds and notice unexplained bald patches, demodectic mange should be on your radar even if the dog isn’t scratching.
How Mange Is Diagnosed
A vet typically diagnoses mange by scraping a small area of affected skin with a blade and examining the sample under a microscope. The mites are tiny (0.2 to 0.6 mm for sarcoptic mites), roughly circular, and covered in small triangular spines. Multiple scrapings from the ears, elbows, and hocks give the best chance of finding them.
Sarcoptic mites are notoriously hard to find, even with several skin scrapings. When a vet strongly suspects scabies based on symptoms but can’t confirm it under the microscope, they’ll often start treatment anyway and see if the dog improves. A blood test that detects antibodies to the sarcoptic mite is also available and can help confirm the diagnosis. Demodectic mites are generally easier to find on skin scrapings because they live in hair follicles in larger numbers.
What Treatment Looks Like
Modern mange treatment has become much simpler than it used to be. The current standard of care for both types involves oral chewable tablets from a class of flea and tick medications that also kill mange mites effectively. These are the same monthly or quarterly parasite prevention products many dog owners already use. Treatment duration varies: sarcoptic mange often clears within a few weeks, while generalized demodicosis may require several months of consistent treatment and follow-up skin scrapings to confirm the mites are gone.
If a secondary bacterial infection is present, your dog will likely need a course of antibiotics alongside mite treatment. Medicated baths or shampoos can help soothe irritated skin and remove crusts during recovery. Hair regrowth typically begins within a few weeks of successful treatment, though heavily damaged skin may take two to three months to look fully normal again.
Can Humans Catch It?
Sarcoptic mange is contagious to humans. The mites can temporarily burrow into human skin, causing itchy red bumps, usually on the arms, waist, or chest. The good news is that canine sarcoptic mites can’t complete their life cycle on human skin, so the rash resolves on its own once your dog is treated. If you’ve been in close contact with a dog that has sarcoptic mange and develop an itchy rash, that’s likely the cause.
Demodectic mange is not contagious. The mites involved are a normal part of the skin ecosystem in most dogs, passed from mother to puppy during nursing. Dogs develop clinical demodicosis when their immune system fails to keep the mite population in check, not because they caught something from another animal.