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Old Dog Resources
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College of Veterinary Medicine
Louisiana State University
DERMATOLOGY SERVICE
Dr.Sandra Merchant, DVM Dr. Carol S. Foil, DVM
Diplomate A.C.V.D. Diplomate
A.C.V.D.
DEMODECTIC MANGE
Demodicosis (red mange) is a skin disease caused by a small mite not visible to the naked eye. This mite lives down in the root of the hair. All normal dogs
have a small population of mites, but only certain animals will get a disease from mite overgrowth. In some cases, the tendency to develop demodectic mange
runs in families.
The disease is seen in TWO FORMS in the dog. There is a localized form where only small areas of the skin are affected, and a generalized
form where the majority of the body and/or the feet are involved. Symptoms include loss of hair and reddening of the skin. Affected areas may be scabby,
crusty and sometimes itchy. Skin infections due to damage by the mite are common. Skin infections can become so severe that they threaten a dog's life,
with ulcers, swelling and fever. Generalized demodicosis is a familial disease and affected dogs and their parents should not be bred.
Diagnosis of demodectic mange is made by examining debris from deep skin scrapings under the microscope. Dogs with generalized disease also require
further testing for underlying health problems.
Treatment of demodectic mange depends on the patient's age and the severity of the disease.
In the localized form, the dog may heal on its own. Many times a cream or gel will be used to aid in healing. It is important that dogs with the
localized form be observed for a worsening of the condition or spread to other areas. Dogs that are intended for breeding should be observed without treatment
to be sure the generalized form does not develop. Infrequently the topical medication may cause the affected areas to look worse before the areas begin to
heal. If a skin infection is present, antibiotics will be needed.
Dogs with generalized demodicosis may require intensive treatment with amitraz (Mitaban®) dips or oral medications. If a skin infection is present,
antibiotics will be needed.
MitabanR dip is the only FDA-approved drug for this disease. WHOLE BODY CLIPPING is
required throughout treatment so that the dip solution can reach the mite down in the hair follicle. Dips are usually preceded by a medicated shampoo to fight
infection. The MitabanR is packaged in individual dosing vials of concentrate which is diluted in water just prior to applying to the patient.
Side affects of MitabanR can be encountered, especially in small dogs, including sedation, decrease in body temperature, loss of appetite,
vomiting and diarrhea. Treatment with an antidote, yohimbine, can be used to decrease the severity of some side effects. Dips are usually applied either
weekly or every two weeks according to the veterinarian's prescription. We generally recommend that dips be applied by grooming technicians in the
veterinarian's hospital.
If no severe side affects are seen, treatment will be continues until repeated skin scrapes reveal no mange mites (typically 6-9 treatments) and for one more
month after that. Scrapings will be performed every 2-4 weeks to evaluate response to treatment. Occasionally, another form of amitraz (TakticR)
is chosen because of lack of availability of MitabanR (but it is not an approved formulation). Different dilution instructions are required for
TakticR.
Ivermectin or Milbemycin Treatment: Some dogs are very sensitive to amitraz and others do not respond even after
many months of therapy. For these dogs, veterinary dermatologists often turn to extra-label use of oral parasiticides that can be used for generalized
demodicosis. Ivermectin is available as a cattle worming agent (IvomecR and generics) and milbemycin is available as a heartworm preventive pill (InterceptorR)
for dogs. At very high daily dosages, these can be used to treat generalized demodicosis successfully in a majority of cases.
NOTE: Some Collies and other English breed herding dogs such as Australian shepherds,
Border collies, Shelties, and Old English Sheepdogs have a nervous system sensitivity to high dose ivermectin and should not be
treated with this drug except in unusual circumstances under the direct supervision of a veterinarian, who will build up to the needed dose very slowly.
For mixed breed dogs of unknown lineage, the ivermectin rule is “White feet, Don’t treat!”
NEUTERING: It is a requirement of the VTH&C that all generalized Demodicosis patients
be neutered as soon as their disease is under control. This is in the best interest for your dog since stress (breeding, heat cycles) can cause recurrence
of the disease. This policy is intended to reduce the incidence of this hereditary disease in pure bred dogs.
Animals with localized demodicosis have a good prognosis with proper care. As the severity of the disease increases, the prognosis worsens. Some dogs with
generalized mange must have regular treatment for the rest of their lives while others may be cured after a variable number of months of treatment.
In all cases it is important to keep your pet as healthy and stress free as possible including a good nutritional diet, regular checkups, routine deworming
and heartworm prevention.
Reprinted with permission from Louisiana State University School of Veterinary Medicine
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