Demodectic Mange

Demodicosis (demodectic mange, follicular mange, red mange) is a skin condition caused by proliferation and infestation of Demodex canis mites within the hair follicles.  The infestation often leads to bacterial folliculitis (skin infection) and may also be associated with furunculous (deep skin infection with pustules). Although the mite is present in the normal skin of dogs and cats, this condition develops when an increased number of mites overwhelm the immune system.  The initial proliferation of mites may be due to a genetic or immunological disorder.

Signs and symptoms include:

• Most commonly alopecia ( hair loss)

• Crusting

• Scaling

• Pustules (a skin elevation filled with pus)

• Comedone (blackhead formation)

• Swelling and draining tracts as associated with furunculous (skin infections)

• Clinical Features:

  • Localized Demodicosis.  A patch of skin develops mild redness and partial loss of hair.  Itching may be present and the area may be covered with fine silvery scales.  The most common sites are the face, forelegs and less frequently on the trunk.  Most cases appear at 3 to 6 months of age.

  • Generalized Demodicosis.  This is one of the most severe canine skin diseases and can widespread from the onset, or develop from poorly defined areas and worsen with time.  Secondary skin infections complicate the mange lesions with multiple pustules and heavy crusting and scaling.

Diagnosis:

• Skin scrapings and examination under the microscope for the mites.

Breed Predisposition:

• Most common in purebred dogs
• Breeds at highest risk: Shar Pei, West Highland White terrier, Scottish terrier, English bulldog, Boston terrier, Great Dane, Weimaraner, Airedale terrier, Alaskan Malamute, and Afghan hound.

Predisposing Factors:

• Age, short hair, poor nutrition, estrus, parturition, stress, endoparasites (internal parasites), debilitating diseases.
• Hereditary predisposition

Treatment:

• Involves the use of a miticide, either topically or orally, to kill the mites.

  • Topical Treatments:  Mitaban l Goodwinol Ointment l Lime Sulfur dips

  • Oral Treatments: 

    • Ivermectin - an injectable medication that is given orally or by SQ injection as an off-label use as directed by your veterinarian.  Ivermectin should not be given to Collies, Shetland sheepdogs (shelties) and other herding dogs and their crosses.

    • Interceptor (milbemycin) - a heartworm medication that is given to chronic, generalized cases of Demodectic mange on a daily basis until resolution.

• Any secondary infection requires antibiotic therapy.

• Deep infections often have gram-negative bacteria in addition to Staphylococcus spp.

• Deep infections require long-term systematic antibiotic therapy from five to six weeks up to several months.