Demodectic mange, also called red mange, demodex, or demodicosis, is a skin disease caused by Demodex canis, a cigar-shaped microscopic mite that is a normal inhabitant of canine skin and found on most healthy dogs. The mite infests hair follicles and occasionally the sebaceous glands of the skin. In dogs with healthy immune systems, the body can naturally manage the number of mites on the skin. However, demodectic mange typically occurs when a dog's immune system is suppressed, allowing the mites to present in excess numbers that cause hair loss on the face or the dog's body. This disease is not contagious to other dogs, but instead, it occurs in dogs with genetic defects that weaken the immune system. Demodectic mange should be treated as soon as possible to prevent the disease from spreading to more areas of the body. If you suspect that your puppy has demodectic mange, consult your veterinarian to begin diagnosis and treatment as soon as possible.
What Is Demodectic Mange?
Demodectic mange is the most common form of mange in dogs, occurring when mites that normally live on the skin of most dogs are able to grow in excess numbers because the dog has a suppressed immune system.
Mange is a generic term that describes a hair loss condition caused by microscopic parasites (called mites) that live on or under the skin. Mites are similar to insects, but they are more closely related to spiders. The life cycle of the mite is spent entirely in the host animal and takes about 20 to 35 days to complete. Spindle-shaped eggs hatch into small, six-legged larvae, which molt into eight-legged nymphs, and then into eight-legged adults.
For instance, canine scabies is another type of mange mite in dogs. Ear mites are another parasite that lives inside the ear canal. Mange is caused by a wide variety of mites, and depending on the mite involved, skin disease can be mild to severe. It may resemble some types of skin allergies.
Symptoms of Demodectic Mange in Puppies
Demodectic mange is always characterized by symptoms of hair loss, but this may be localized or generalized depending on the condition's progression and severity. Puppies are usually affected before reaching 18 months of age. These types can affect different parts of the body:
Mild Facial Hair Loss (Localized Disease)
Demodectic mange begins as a localized disease that is limited to a spot or two on the face and around the eyes. It may also present in small patches on the legs. Localized demodicosis is quite common in puppies, and it is usually a mild disease that goes away by itself or with the use of topical treatments. It typically consists of one to five small, circular, red, and scaly areas of hair loss around the eyes and lips, or on the forelegs. The affected areas may or may not be itchy, and skin infections can occur alongside this disease that require additional treatment.
In most cases, the localized form resolves as the dog's immune system matures and gets the mites under control. It rarely recurs. An adult-onset disease is considered rare, and when it does occur, it usually is a result of compromised immunity associated with other systemic diseases.
Severe Bodily Hair Loss (Generalized Disease)
When the localized form spreads, involving large areas of the body with severe disease, it is considered generalized. Generalized demodicosis is a severe disease characterized by massive patchy or generalized hair loss and skin inflammation, often complicated by skin infections that may cause ulcers, swelling, and fever that require antibiotics to treat.
Mites (all stages) may also be found in lymph nodes, intestinal wall, blood, spleen, liver, kidney, bladder, lung, urine, and feces. The skin is red, crusty, and warm, and has many pustules. It bleeds easily, becomes very tender, and has a strong "mousy" odor due to bacterial infection on the skin. When infection is present, an immediate visit to the veterinarian is necessary to begin antibiotic treatment.
Causes of Demodectic Mange
Demodectic mange typically affects puppies, but it can also affect adult and senior dogs for non-genetic reasons. In any case, immune-compromised individuals are unable to stop mite proliferation. The following causes can occur:
- Inherited genes: Puppies can inherit genes from their parents that weaken their immune systems, allowing demodectic mange to develop. Any breed can be affected, but an inherited predisposition appears to occur in breeds including the Old English sheepdog, collie, Afghan hound, German shepherd, Akita, Doberman pinscher, English bulldog, Great Dane, dachshund, Chihuahua, chow chow, boxer, pug, shar-pei, beagle, pointer, and several terriers.
- Weakened immune system: Even if a dog is not born with genes that increase the likelihood of demodectic mange, it can still develop this condition if its immune system is weakened later in life. This type of mange can affect seniors and adult dogs with weakened immune systems due to medications or other diseases.
Diagnosing Demodectic Mange in Puppies
If your puppy is showing signs of demodectic mange, your veterinarian will diagnose the disease by taking skin scrapings or biopsies that will be examined under a microscope in the laboratory. Since these mites live on most dogs, the diagnosis will be confirmed based on the number of mites inhabiting your dog's skin. Once demodectic mange is detected, your veterinarian can begin discussing treatment options based on the severity of the condition.
Treatment & Prevention
Occasionally, treatment is not necessary for localized demodicosis, which may clear up by itself as puppies grow and develop stronger immune systems. Treatment may also include topical medication as necessary. However, generalized demodicosis requires aggressive therapy. Pet owners should prepare for a lengthy process to aid in recovery.
Puppies with generalized demodectic mange are typically treated with whole-body dips and specialized shampoos. These dips contain an insecticide that can sometimes lead to serious side effects for puppies and their owners who come in contact with them, but most dogs experience fewer problems as treatments continue and their natural tolerance to the medication is increased. These side effects can include drowsiness, vomiting, lethargy, and drunken behavior. Products for the treatment of demodectic mange should only be used with veterinary supervision.
Antibiotic therapy is required to fight any secondary skin infections that develop. Regular baths with exfoliating shampoos such as those containing benzoyl peroxide are helpful.
Since demodectic mange is usually an inherited condition, this disease cannot typically be prevented. However, older dogs with weakened immune systems may respond to immune-boosting options that can decrease their likelihood of developing it. Your veterinarian may recommend a specialized diet or nutritional supplements to strengthen your dog's immune system when they see demodectic mange as a risk.
Prognosis for Puppies With Demodectic Mange
The weakened immune system that leads to demodectic mange can make treatment and recovery difficult, so owners should prepare for continuous treatment and possible relapses. Localized demodectic mange can usually be treated successfully, but puppies may have issues until their immune system is fully developed around the age of 18 months old. Generalized demodectic mange, on the other hand, may require lifelong treatments and check-ups with your veterinarian.
Demodectic Mange in Dogs. VCA Animal Hospitals.
Demodex. Louisiana State University Veterinary Teaching Hospital.
Mange in Companion Animals. University of Florida Institute of Food and Agricultural Sciences.