Sarcoptic Mange (Scabies) in Dogs: Intense Itching and How to Treat It
Sarcoptic mange, caused by Sarcoptes scabiei mites, produces severe itching in dogs. Learn the signs, how it spreads, and why prompt treatment is essential.
Source: Veterinary knowledge. Sarcoptic mange (canine scabies) is a highly contagious skin disease caused by the microscopic mite Sarcoptes scabiei. These mites burrow into the skin, causing intense itching, hair loss, and crusty skin lesions. It is one of the most uncomfortable conditions a dog can experience. The good news: it is completely treatable with modern medications. In Macau, where stray dogs are common, sarcoptic mange remains a significant concern for pet dogs that come into contact with infected animals.
- Caused by Sarcoptes scabiei mites that burrow into the skin
- Intense, relentless itching is the hallmark sign
- Highly contagious between dogs — and can temporarily infect humans
- Lesions typically start on the ear margins, elbows, and hocks
- Diagnosis can be challenging — skin scrapings are only positive 50% of the time
- Modern oral and topical treatments are highly effective
The Sarcoptes Mite Life Cycle
Female Sarcoptes mites burrow into the upper layers of the skin to lay eggs. The eggs hatch in 3-5 days, and the larvae develop into adults in about 2 weeks. The mites survive only a few days off the host animal, but the intense itching they cause during that time can be devastating. The entire life cycle occurs on the dog — unlike fleas, sarcoptes mites do not live long in the environment. However, they can survive on bedding and grooming tools for 2-3 days, so these must be cleaned or discarded during treatment.
Signs and Symptoms
The hallmark of sarcoptic mange is intense, unrelenting itching — dogs will scratch, bite, and rub themselves raw. The itching is often worse at night (when the mites are more active). Lesions typically begin on the ear margins (the edges of the ears), elbows, hocks (ankles), and chest, then spread across the body. The skin becomes red, crusty, and thickened. Hair loss progresses from focal patches to widespread areas. Because dogs scratch so intensely, secondary bacterial skin infections are very common and add to the discomfort. Some dogs develop a condition called 'scabies rash' — a widespread allergic reaction to the mite antigens.
Diagnosis Challenges
Diagnosing sarcoptic mange can be surprisingly difficult. The standard test — skin scraping, where the vet scrapes the surface of affected skin and examines the debris under a microscope — only identifies mites about 50% of the time. This is because the mites burrow deep and there are relatively few of them. A positive scraping confirms the diagnosis, but a negative scraping does not rule it out. Many vets use the 'pedal-pinnal reflex' test: rubbing the ear margin often triggers an intense scratching reflex in dogs with scabies. Response to treatment is often used as a diagnostic tool — if the dog improves dramatically with anti-mite treatment, the diagnosis is confirmed.
Treatment and Prevention
Modern treatments for sarcoptic mange are highly effective. Oral medications containing sarolaner (Simparica), fluralaner (Bravecto), or afoxolaner (NexGard) kill mites rapidly with a single dose. Ivermectin (oral or injectable) is also effective but must be avoided in certain breeds (Collies, Shelties, and related breeds with the MDR1 gene mutation). Topical selamectin (Revolution) applied weekly for 3-4 weeks is another option. All dogs in the household must be treated simultaneously, even if only one shows symptoms. Bedding should be washed in hot water or discarded. The itching may persist for 2-3 weeks after mites are killed due to ongoing allergic reaction — this does not mean treatment failed.
- Your dog is scratching relentlessly, especially at the ears and elbows
- Hair loss and crusty skin lesions are appearing and spreading
- The itching is worse at night
- Other dogs in the household are starting to itch
- Family members are developing itchy red bumps (temporary human infection)
- Your dog has been in contact with stray or shelter dogs recently
Royal Veterinary Center can diagnose and treat sarcoptic mange quickly. If your dog is scratching intensely or developing crusty skin lesions, early treatment prevents suffering and stops the spread. Call +853 6677 6611 to book an appointment.
+853 6677 6611