What Is Demodectic Mange in Dogs?
Demodectic mange, also recognized as red mange, denotes a parasitic skin ailment triggered by mites like Demodex canis (the most prevalent), Demodex injai, or Demodex cornei. When observed under the microscope, these mites display a cigar-shaped appearance with eight short legs.
Normally, these mites inhabit hair follicles and pose no threat to their host, especially when the immune system is robust. However, in dogs with immature or compromised immune systems, allowing the mite population to proliferate, clinical symptoms like hair loss and red, scaly skin lesions manifest.
Typically, the mite exists in small numbers within the hair follicles of the skin. Transmission of Demodex often occurs from mother to puppy during lactation, primarily due to the puppy’s underdeveloped immune system. Exposure of a healthy dog to one with demodectic mange doesn’t pose a risk, as the condition necessitates a weakened immune system for development.
It’s important to note that demodectic mange isn’t transmissible from dogs to humans, nor is it contagious among other dogs, as its development requires a compromised immune system.
Symptoms
Symptoms of demodectic mange in dogs typically manifest as follows:
- Hair loss (Alopecia)
- Skin scaling
- Presence of bumps on the skin (Papules)
- Changes in skin pigmentation
- Thickening of the skin
The degree of itchiness experienced can vary, influenced by secondary skin infections or whether the lesions are localized or widespread across the body.
In puppies, lesions often initiate around the facial and head regions, attributed to suckling from the mother’s teat; however, they can occur anywhere on the body. In more severe cases of generalized demodectic mange, additional symptoms may include pain, lethargy, fever, draining wounds, and skin swelling. Furthermore, ear infections may arise if the mite infiltrates the ear canals.
Causes
The occurrence of demodectic mange in dogs is primarily attributed to the proliferation of demodectic mites, which typically inhabit the skin without causing harm to their host. Mange develops when these mites overgrow within the hair follicles, particularly in individuals with weakened immune systems. This vulnerability is commonly observed in puppies, whose immune systems are still developing, as well as in older dogs with underlying illnesses that compromise their immune function.
It’s worth noting that demodectic mites are present on the skin of all individuals, including normal, healthy dogs and humans. However, when the immune system is compromised, these mites can proliferate, resulting in itching and the onset of mange. The transmission of demodectic mites typically occurs between dogs, particularly from mother to puppy during early stages of life.
Diagnosis
Veterinarians typically diagnose demodectic mange in dogs through several methods, with skin scraping or hair plucking and cytology being the most common. This non-invasive test involves using a scalpel blade to scrape the skin deeply enough to cause mild irritation or bleeding, which is necessary to reach the depth where demodex mites reside. Alternatively, hair can be plucked from the root for examination. The collected sample is then evaluated under a microscope, with the presence of mites indicating a positive result.
In some cases, mites can be detected through fecal flotation or fecal testing, as dogs may ingest them while licking or chewing their skin. Polymerase chain reaction (PCR) testing is another diagnostic option, although it may yield false negative results and is often unnecessary when the diagnosis is clear from other methods.
In instances where a dog does not respond to treatment or when diagnosis remains uncertain despite other tests, veterinarians may opt for a skin biopsy. This procedure is particularly considered in more severe, generalized cases of demodectic mange.
Treatment
Treatment approaches for demodectic mange in dogs vary depending on the severity and extent of the infection. Not all cases necessitate immediate intervention. Localized instances, confined to a small area of the body, often resolve spontaneously within 1-2 months without treatment. Alternatively, topical medications like moxidectin and imidacloprid can effectively address localized infections.
In cases where demodectic mange becomes generalized, medical intervention is recommended to alleviate symptoms. Miticidal treatment, administered orally or topically, is the primary therapy. Medications such as ivermectin, milbemycin, doramectin, amitraz, fluralaner (Bravecto), afoxolaner (Nexgard), sarolaner (Simparica), and lotilaner (Credelio) are commonly prescribed. However, dogs with MDR1 mutations should avoid ivermectin, and genetic testing can identify this mutation.
Miticidal therapy should continue until two consecutive negative skin scraping or hair plucking tests confirm resolution. Special shampoos containing benzoyl peroxide are often recommended to open and flush hair follicles, facilitating the penetration of dip and topical treatments. Prior to initiating treatment, it’s crucial to discuss the potential risks and benefits with your veterinarian.
In cases where secondary skin infections arise due to inflammation, antibiotic therapy may be necessary. Addressing the skin infection may precede the clearance of demodectic mange.
Furthermore, it’s advisable to refrain from breeding dogs with generalized demodex infections, as the condition is believed to stem from underlying genetic and/or immune system factors contributing to mite overgrowth.
Living and Management
Recovery from demodectic mange in dogs is generally favorable with timely and appropriate therapy. Dogs often respond well to treatment, although some may require ongoing care due to secondary infections or underlying systemic illnesses. In cases where treatment is inadequate or underlying medical conditions are poorly managed, demodectic mange can be fatal for dogs.
Unlike certain conditions, demodectic mange doesn’t necessitate environmental cleaning since it typically doesn’t spread between dogs. However, it’s still advisable for dogs to receive monthly or tri-monthly miticidal preventatives as a precaution. Regular use of miticidal preventatives helps safeguard dogs against various mites, fleas, and ticks, unless otherwise advised by your veterinarian.
Demodectic Mange in Dogs FAQs
Is demodectic mange transmissible to humans?
Demodectic mange does not spread to humans.
How long does it typically take for demodectic mange to disappear?
The duration for demodectic mange to resolve varies, ranging from weeks to months, depending on whether it’s localized or generalized, and if there are any secondary infections or underlying conditions. Each dog’s response to treatment differs, so there isn’t an exact timeframe for recovery.
Can demodectic mange vanish without treatment?
In mild cases, demodectic mange may resolve spontaneously. Typically, mild, localized infections take 1-2 months to resolve without intervention.
How long is a dog infectious with demodectic mange?
Dogs with demodectic mange pose no risk of transmission to other dogs, pets, or humans.