Mange (Demodex / Sarcoptic)

Mange in dogs refers to skin disease caused by mites. The two main types have different causes, presentations, and management:

Demodectic mange (demodicosis): Caused by Demodex mites that live in hair follicles. Small numbers of Demodex mites are a normal part of the skin flora - they become problematic when the immune system fails to control their population. Localised disease in puppies often resolves spontaneously. Generalised disease in puppies or adult-onset disease in older dogs indicates immune dysfunction.

Sarcoptic mange (canine scabies): Caused by Sarcoptes scabiei mites that burrow into the skin, causing intense itching. Highly contagious between dogs and can temporarily infest humans (causing a self-limiting rash). Not part of normal skin flora - requires direct contact with an infected animal.

Demodectic mange: what to monitor

Localised demodicosis (most common in puppies, often resolves without treatment):

• Small patches of hair loss, typically on the face around the eyes and muzzle, or on the legs
• Mild scaling within the patch
• Usually minimal or no itching
• Log the number, size, and location of patches; photograph to track change

Generalised demodicosis:

• Multiple patches or widespread hair loss across the body
• Often secondary bacterial infection - crusting, pustules, discharge
• Can occur in puppies (juvenile-onset, often resolves with treatment) or adult dogs (adult-onset, often indicates systemic illness or immunosuppression)

Adult-onset generalised demodicosis in an older dog warrants investigation for an underlying immunosuppressive condition (Cushing's disease, hypothyroidism, malignancy, long-term steroid use).

Daily monitoring during treatment:

• Number and size of lesions
• Signs of secondary infection (discharge, odour, increased redness)
• Itching level (usually low in demodicosis; significant itching suggests concurrent infection)
• Response to treatment - improvement typically visible within 4–8 weeks

Sarcoptic mange: what to monitor

Sarcoptic mange causes intense, relentless itching - more severe than almost any other skin condition. Classic signs:

• Intense pruritus (itching): Particularly on the ears, elbows, hocks, and ventral abdomen. Scratch at any ear margin with a fingernail - many dogs with sarcoptic mange will scratch reflexively (the pinnal-pedal reflex).
• Self-trauma: Hair loss from scratching, crusting, thickened skin, and secondary bacterial infection
• Rapidly spreading lesions: Sarcoptic mange spreads quickly across the body
• Contagion in household contacts: Other dogs (and sometimes humans - check for a self-limiting itchy rash on your own forearms and abdomen)

Daily monitoring during treatment:

• Itching severity (should reduce significantly within 2–4 weeks of appropriate treatment)
• Lesion distribution and resolution
• Other pets in the household (all dogs in contact must be treated simultaneously)
• Human household members (self-limiting human infestation usually resolves when the dog is treated)

Diagnosis

Skin scraping and microscopy - looking for mites under the microscope - confirms demodectic mange and can detect sarcoptic mange, though Sarcoptes mites are notoriously difficult to find on scrapes. A strong clinical picture plus characteristic response to treatment often confirms sarcoptic mange.

Treatment

Demodicosis: Localised cases in puppies often require no treatment. Generalised cases are treated with monthly isoxazoline treatments (fluralaner, afoxolaner, sarolaner - the flea and tick treatments also kill Demodex mites effectively) or oral milbemycin. Treatment continues until skin scrapings are negative.

Sarcoptic mange: Isoxazoline treatments (Bravecto, NexGard, Simparica) are highly effective and fast-acting. All dogs in the household must be treated simultaneously. Environmental treatment is less critical than for some other parasites but vacuum thoroughly and wash bedding.

When to contact your vet

Contact your vet soon if:

• A puppy has multiple patches of hair loss not resolving spontaneously within 4 weeks
• Widespread or rapidly spreading mange lesions
• Intense itching beginning shortly after contact with an unknown dog
• A household member has developed a rash after the dog became itchy

Frequently Asked Questions

Will my dog transmit Demodex to me? Demodex canis is host-specific and cannot establish on humans. You cannot get demodectic mange from your dog.

Can I catch sarcoptic mange from my dog? Temporarily, yes. Sarcoptes scabiei var. canis can briefly infest human skin, causing an itchy rash - typically on the forearms and abdomen where the dog sits. Human infestation is self-limiting once the dog is treated.

My puppy has a small patch of hair loss around one eye - should I be worried? Localised demodicosis in a puppy (a small number of lesions, typically on the face) often resolves spontaneously as the immune system matures. Have your vet confirm the diagnosis with a skin scrape and monitor for spread - more than five patches or rapidly worsening lesions warrant treatment.

My adult dog has developed mange. Is there something wrong with their immune system? Adult-onset generalised demodicosis often suggests immune dysfunction. Common causes include Cushing's disease, hypothyroidism, long-term steroid administration, and occasionally underlying cancer. Your vet will investigate for an underlying cause.

How long does mange treatment take? Sarcoptic mange typically shows significant improvement within 2–4 weeks. Demodicosis takes longer - 3–6 months for generalised cases, confirmed negative by consecutive negative skin scrapings. Treatment should not be stopped based on clinical improvement alone.