Demodicosis (Red Mange) in Dogs

Demodicosis (Red Mange) in Dogs

By: Dr. Rosanna Marsalla

Section: Veterinary Care In-depth

Diagnosis In-depth

Diagnosis of demodicosis is based on clinical presentation and positive deep skin scrapings.

  • Skin scrapings. When performing deep skin scrapings it is important to avoid scarred, fibrotic and ulcerated areas. Areas with blackheads are suggested areas for skin scrapings.

    The skin should be squeezed and several skin scrapings should be done in the same direction of the hair growth until capillary bleeding is obtained. Hair plucking may be a suitable technique in some dogs in which skin scrapings may not be positive in spite of suggestive clinical signs.

  • Skin biopsy. In most cases mites can be found on skin scrapings if they are performed appropriately. The exceptions are shar-peis, lick granulomas and severe pododermatitis with deep pyoderma. In these cases a skin biopsy may be necessary to make a diagnosis.

    Folliculitis, perifolliculitis and a pyogranulomatous infiltrate are commonly found on histopathology.


    Treatment In-depth

  • Three forms of treatment currently exist for demodicosis. They are amitraz dips (Mitaban®), milbemycin (Interceptor®) and ivermectin (Ivomec®).

  • Mitaban is the only FDA approved treatment for demodicosis. The approved protocol is one dip every two weeks until three consecutive biweekly negative skin scrapings are obtained. Based on the results of previous studies, however, most veterinarians use mitaban weekly rather than every two weeks. The increased frequency significantly increases the efficacy of this therapy.

    The mixture (1 vial/2 gallons of water) should be prepared fresh every week and should not be stored and re-used for additional dips. Treatments should be completed in a well ventilated area and gloves must be worn when administering therapy.

    Dogs with medium/long hair coat should be clipped. Dogs should be bathed before the dip. A follicular flushing agent is recommended (benzoyl peroxide shampoo) to increase the efficacy of the Mitaban® dip.

    Most dogs require six to nine dips to have negative skin scrapings. Therapy should be continued until three consecutive negative scrapings are obtained. Dogs should not be allowed to get wet in-between dips. Dogs should not be sedated the same day of the dip.

    Use 25 to 50 percent strength in toy breeds as they are at increased risk for adverse effects. Adverse effects include depression, anorexia, vomiting, itchiness, low body temperature, staggering, slow heart rate, sedation, high blood sugar level and death. Yohimbine can be used as reversal agent for amitraz toxicity. Use label dose or 2 label dose subcutaneously pre- and/or post-dip.

  • milbemycin at 1.5 to 2.5 mg/kg per day is an alternative treatment for demodicosis. The average dog will require 90 days of therapy. In cases longer treatment may be required. Milbemycin has the same potential for adverse effects as ivermectin has thus it should be used with extreme caution in ivermectin-sensitive breeds.

  • Ivermectin daily at 200 to 600 mcg/kg until 3 negative skin scrapes is another option. Efficacy is dose-dependent thus increased success is seen at the higher end of the dosing interval. It is recommended to build up the dose gradually to minimize the occurrence of severe adverse effects. It should not be used in ivermectin sensitive breeds (e.g. collies, shelties, Australian shepherds and other breeds). Monitoring of therapy consists in making scrapings from 5 representative sites, always including muzzle and 2 locations between toes. This is the treatment of choice of many veterinarians. It is given daily until resolution of signs then gradually weaned over 2 to 3 months.

  • Moxidectin (Cydectin Injection) has also been recommended and used with some success.

  • Vitamin E has been used as a immunomodulator as an adjunctive therapy to the above standard therapies.

  • Antibiotics may be recommended to treat secondary skin infections and pyoderma.

    Mite counts should be recorded and animal should be re-scraped in the same sites and new lesions every 30 days. Treatment should be continued at least 30 days beyond last totally negative scraping.

    Dogs should be scraped one month after discontinuation of therapy. It is important to remember that besides the eradication of the mites it is vital to address the secondary bacterial skin infections and ensure that no concurrent diseases exist that could impair the ability to respond to treatment.

    Follow-up

    The juvenile onset demodicosis is genetically inherited thus affected animals should not be used for breeding.

    The adult onset form of the disease is related to an underlying disease and there is no prevention for it.

     
    Printable Version
     
    Have a Pet Question?
    Send Your Pet Question to Dr. Jon
    and His Staff of Veterinarians Ask Dr. Jon
    Dr. Jon's Newsletter
    Yes! Send Me the Latest Health Information, Pet Tips, Pet Stories and more...
     
     

    Related Articles

    • 1 Skin Discharge or Odor in Dogs

      Skin odor is a common manifestation of a skin infection; the most common skin infections are bacterial (superficial pyoderma) and yeast (Malassezia dermatitis) infections.

      Read MoreRead More
    • 2 Pyoderma in Dogs (Bacterial Skin Infection, Pus in the Skin)

      Pyoderma is a bacterial infection of the skin. Pyoderma can be divided into surface pyodermas (infection on the skin surface), superficial pyoderma (infection within the skin) or deep pyoderma (infection...

      Read MoreRead More
    • 3 Skin Lesion or Sore in Dogs

      There are many different types of skin lesions that can occur in the skin of dogs, and each lesion or combination of lesions can be caused by multiple diseases and conditions.

      Read MoreRead More
    • 4 Alopecia (Hair loss) in Dogs

      Alopecia is the complete or partial lack of hair in any area of the skin where hair would normally be found. In dogs, it may be caused by self-trauma, hair follicle diseases or the failure of hair to grow...

      Read MoreRead More
    • 5 Skin Scraping

      A skin scraping is a commonly performed test that can help diagnose certain skin inflammations, fungal infections, and skin cancer and is quite effective in determining the presence of mites.

      Read MoreRead More
  • Related Articles
    • 1 Alopecia (Hair loss) in Dogs

      Alopecia is the complete or partial lack of hair in any area of the skin where hair would normally be found. In dogs, it may be caused by self-trauma, hair follicle diseases or the failure of hair to grow...

      Read MoreRead More
    • 2 Pyoderma in Dogs (Bacterial Skin Infection, Pus in the Skin)

      Pyoderma is a bacterial infection of the skin. Pyoderma can be divided into surface pyodermas (infection on the skin surface), superficial pyoderma (infection within the skin) or deep pyoderma (infection...

      Read MoreRead More
    • 3 Skin Discharge or Odor in Dogs

      Skin odor is a common manifestation of a skin infection; the most common skin infections are bacterial (superficial pyoderma) and yeast (Malassezia dermatitis) infections.

      Read MoreRead More
    • 4 Skin Lesion or Sore in Dogs

      There are many different types of skin lesions that can occur in the skin of dogs, and each lesion or combination of lesions can be caused by multiple diseases and conditions.

      Read MoreRead More
    • 5 Skin Scraping

      A skin scraping is a commonly performed test that can help diagnose certain skin inflammations, fungal infections, and skin cancer and is quite effective in determining the presence of mites.

      Read MoreRead More
     

    Over 10,000 Veterinarian Approved Articles

    Related Articles
    • 1 Alopecia (Hair loss) in Dogs

      Alopecia is the complete or partial lack of hair in any area of the skin where hair would normally be found. In dogs, it may be caused by self-trauma, hair follicle diseases or the failure of hair to grow...

      Read MoreRead More
    • 2 Pyoderma in Dogs (Bacterial Skin Infection, Pus in the Skin)

      Pyoderma is a bacterial infection of the skin. Pyoderma can be divided into surface pyodermas (infection on the skin surface), superficial pyoderma (infection within the skin) or deep pyoderma (infection...

      Read MoreRead More
    • 3 Skin Discharge or Odor in Dogs

      Skin odor is a common manifestation of a skin infection; the most common skin infections are bacterial (superficial pyoderma) and yeast (Malassezia dermatitis) infections.

      Read MoreRead More
    • 4 Skin Lesion or Sore in Dogs

      There are many different types of skin lesions that can occur in the skin of dogs, and each lesion or combination of lesions can be caused by multiple diseases and conditions.

      Read MoreRead More
    • 5 Skin Scraping

      A skin scraping is a commonly performed test that can help diagnose certain skin inflammations, fungal infections, and skin cancer and is quite effective in determining the presence of mites.

      Read MoreRead More
    Advertisement
    Advertisement