How does a dog get mange?

Mange is one of those problems that can feel urgent and personal: it affects your dog’s skin, your household routine, and sometimes even human family members. Below is a practical, veterinarian-informed guide to how dogs get mange, what that means for your pet and home, and the sensible steps to take right away and long-term.

Why mange deserves your attention: the risks for your dog

Understanding mange matters because it is primarily a skin disease that can escalate quickly from an irritation to a painful, infected condition. Puppies, senior dogs, and animals with weakened immune systems are more likely to develop severe signs, and living with an affected dog can change day-to-day care needs in ways that are stressful for families. I typically see owners delay seeking help because they hope the problem will “just go away,” which often allows secondary infections and discomfort to worsen.

Your household situation can influence both risk and urgency. New shelter dogs, dogs recently boarded in kennels, or animals that have had contact with stray dogs are situations that commonly prompt concern. If more than one pet in the home starts to itch, or if a person in the house develops an unexplained rash after close contact, that is the moment to call your veterinarian for triage rather than waiting.

Mange explained — what it is and how it affects dogs

Mange is a term used to describe skin disease caused by tiny parasitic mites. Two forms are most relevant in dogs: sarcoptic mange, caused by Sarcoptes scabiei var. canis, which is highly contagious between dogs and can cause transient skin irritation in people; and demodectic mange, caused by Demodex mites that normally live in small numbers in dog hair follicles and usually become a problem when a dog’s immunity is compromised. Typical visible signs include intense scratching, patchy hair loss (often around the face, ears, and elbows), reddened or crusted skin, and sometimes a foul odor that suggests a secondary infection.

How mange develops: mites, immunity, and the science behind the rash

Mites are tiny arthropods that live on or in the skin. Sarcoptes mites burrow into the outer layers of skin and lay eggs; the egg-to-adult process is likely completed in roughly two to three weeks, and the resulting irritation often triggers a strong allergic-type response from the host. Demodex mites live deeper in hair follicles and sebaceous glands and are normally controlled by the immune system; when control is lost—because of genetic predisposition, stress, or immune suppression—mite numbers can expand and damage follicles, producing localized or generalized disease.

The host immune response is a major driver of clinical signs. In sarcoptic infestations, hypersensitivity to mite proteins tends to produce intense itching and widespread inflammation even though the number of mites may be relatively low. With demodicosis, the damage is often from mite overgrowth and follicular destruction, which can permit bacteria to invade and create infections. Skin barrier function—sebum, hair follicle integrity, and resident microbes—can become disrupted by excessive scratching or by the mites themselves, amplifying inflammation.

There is likely a genetic component to some dogs’ susceptibility to demodex; certain breeds and some family lines show higher rates. Immune-suppression from disease or medications can also make a dog more prone to turning a low-level mite presence into a clinical problem.

Where and when dogs pick up mange: environmental triggers and timing

External and temporal factors matter. Stress and poor nutrition may weaken skin defenses and immunity, increasing the risk that mites will multiply. High-density settings such as shelters and kennels provide more opportunities for sarcoptic mites to pass from dog to dog; bringing a new dog into a household from such settings is a common trigger for owner concern. Climate can have an influence too: warm, humid conditions may favor survival of off-host stages or increase close-contact behaviors, though mites primarily complete their lifecycle on the host.

Age plays a role in timing. Puppies often show demodectic problems when their immature immune systems do not control normal Demodex populations; adults with new-onset generalized demodicosis are more likely to have an underlying health issue. Sarcoptic disease may appear rapidly after exposure, whereas demodicosis often has a slower, progressive course.

Red flags and subtle signs: spotting mange early

Some signs can suggest a simple local issue, while others indicate severity or complications. Intense, persistent itching—especially if the dog is scratching at night or causing raw sores—should be considered a red flag. Rapid spread of lesions, thick crusts, or folded skin with heavy scaling is characteristic of sarcoptic mange and often requires prompt attention.

Secondary bacterial infection is common; telltale clues include pustules, oozing, a strong odor, or areas of hair stained with discharge. If you notice fever, lethargy, or swollen lymph nodes, that suggests systemic involvement that needs veterinary evaluation. Human symptoms such as transient, itchy spots on people who have had close contact, or multiple animals in the household showing signs, increase the urgency for treatment and hygiene measures.

Immediate steps to take if you suspect your dog has mange

If you suspect mange, separate the affected dog from other animals and vulnerable people (children, elderly, immunocompromised) while you arrange veterinary care. Photograph the lesions and write down when you first noticed changes, any recent boarding or shelter exposure, travel history, flea or tick treatments, and any medications your dog has received. These details help the veterinarian assess risk and choose diagnostics. Avoid applying unproven pesticides or harsh consumer chemicals to your dog; some over-the-counter products can be harmful, especially to small dogs, cats, or certain breeds.

Try to limit the dog’s self-trauma: a soft plastic Elizabethan collar or short supervised leash walks can reduce new skin damage before treatment begins. Call your clinic for triage advice—many practices will ask about household contacts and may schedule an expedited appointment for suspected sarcoptic cases because of contagion risk.

Treatment options and home-care priorities for recovery

Diagnosis can include superficial and deep skin scrapings, acetate tape impressions, or PCR testing for sarcoptic DNA; however, mites can be hard to find, and a negative scrape does not rule out sarcoptic mange. Because of this, veterinarians sometimes recommend a therapeutic trial when clinical signs and history are strongly suggestive.

Treatments have advanced in recent years. Oral isoxazoline drugs (examples include fluralaner, afoxolaner, sarolaner, and lotilaner) are commonly used and are effective against both forms in many cases; these are prescription-only and have a dosing schedule set by your veterinarian. Topical options such as selamectin or lime-sulfur dips may be useful in certain cases, and amitraz dips are still used for sarcoptic disease under veterinary guidance. Ivermectin and milbemycin can be effective but may be used off-label and carry breed-specific safety concerns; dogs with known sensitivity (MDR1 mutations) require caution.

Supportive care is often needed: medicated baths (chlorhexidine or benzoyl peroxide) help control secondary bacteria and remove crusts, topical antibiotics may be applied for localized infection, and systemic antibiotics are sometimes prescribed for widespread pyoderma. Nutritional support and supplements such as omega-3 fatty acids may aid skin healing. Treatment duration varies; for sarcoptic mange, dogs are generally considered effectively treated after several weeks of therapy and improvement in clinical signs, while demodicosis treatment may continue for months until follow-up scrapings or clinical assessments indicate control. Regular rechecks at 4–8 week intervals are typical so the vet can confirm progress and adjust therapy.

Containment and cleanup: preventing spread in your home and yard

Environmental steps reduce the chance of reinfestation and protect other household animals. Wash bedding, blankets, collars, and toys in hot water and dry them on a high-heat cycle when material allows; heat is more reliable than detergent alone for killing mites. Vacuum floors, furniture, and vehicle seats regularly and dispose of vacuum bags or contents promptly. In situations of sarcoptic mange, many veterinarians recommend treating all in-contact dogs at the same time because the mites spread readily; demodex usually does not require household-wide treatment because it is generally not contagious in the same way.

Be cautious with chemical sprays: permethrin-containing products can be dangerous to cats and must never be used around them. Use pet-safe disinfectants and follow label directions, or ask your veterinarian for recommended products. Reintroduction to group settings—dog parks, daycare, kennels—should wait until a veterinarian confirms clinical resolution and, for contagious forms, until the prescribed treatment course is complete and the dog has been rechecked.

Practical gear checklist for treating and managing mange

• Veterinary-prescribed medications (oral isoxazolines, topical selamectin, or clinic-administered dips) and applicators provided or demonstrated by the clinic.
• Medicated shampoos (chlorhexidine, benzoyl peroxide) and, where recommended, lime-sulfur dip supplies; rubber grooming gloves to gently remove crusts.
• Washable isolation bedding and an easily cleaned crate or room; disposable gloves and pet-safe surface disinfectants for handling soiled items.

When mange won’t clear or keeps returning: troubleshooting and next steps

Recurring or non-responsive mange should prompt a deeper look. I typically reassess overall health, nutrition, and any medications that could be suppressing immunity. Additional diagnostics—skin biopsies, fecal testing, or bloodwork—may be useful to look for underlying causes such as endocrine disease or immune suppression. If one class of medication fails, switching to an alternative therapy under veterinary supervision is reasonable; resistance has not been widely documented for most modern therapies, but incorrect dosing or incomplete environmental control are common reasons for apparent treatment failure.

Monitor household members and other pets closely; recurrent cases sometimes reflect an untreated contact or a re-exposure event. Ongoing communication with your veterinarian and scheduled rechecks help ensure that treatment goals—relief of pruritus, resolution of lesions, and elimination of mites—are met with minimal risk to the rest of the family.

References and further reading from veterinary sources

• Merck Veterinary Manual: “Sarcoptic Mange (Scabies) in Dogs” and “Demodicosis (Demodectic Mange)” — Merck & Co., Inc., Veterinary Manual (searchable pages with clinical guidance).
• Miller, W.H., Griffin, C.E., & Campbell, K.L. Muller and Kirk’s Small Animal Dermatology, 8th ed. — comprehensive textbook covering canine parasitic skin diseases and treatments.
• American Veterinary Medical Association (AVMA): “Mange in Dogs” resources and client information sheets.
• Centers for Disease Control and Prevention (CDC): “Scabies” and zoonotic considerations — guidance on human risk and public health precautions.
• World Small Animal Veterinary Association (WSAVA) guidelines and consensus statements on diagnosis and treatment of parasitic skin disease in dogs.