Demodectic mange (demodicosis)

Demodicosis (Demodectic mange)

Demodex canis
is a microscopic parasite which lives in the hair follicles of the dog. It is transmitted during the first days of life from mother to puppy and is part of the normal cutaneous flora. But, in some cases, it can develop into a skin condition named demodicosis (demodectic mange) (localized or generalized, juvenile or adult).

Among dogs several Demodex are described:

  • Demodex Canis (250-300µm)
  • Demodex short-bodied (Demodex Cornei). Lives on the skin surface (90-148µm)
  • Demodex long bodied (Demodex Injai). Stays mainly in the pilo-sebaceous units (334-368µm)

Among cats this parasite is much less frequent. But it can take advantage of an immuno-depressed area (Feline Leukemia Virus (FeLV), Cats with AIDS (FIV), or in cases where there has been use of medicines reducing immunity (chemotherapy, cortisone...).
Three species are described:

  • Demodex Cati (160-200µm)
  • Demodex Gatoi: on the surface of the skin (110µm)
  • Demodex Sp (110-146µm)

The clinical signs of Demodicosis (loss of hair, redness of the skin (erythema), comedones...) appear in the first months of life (juvenile stage). These can be localized and may heal without treatment, or they can become generalized and require a long treatment programme of several months. The adult form often follows an induced reduction of immunity, for example, by a tumor, an excess of cortisone (secreted or administered), or associated with a hypothyroid condition.

Demodicosis is often complicated by secondary bacterial infection provoking some pustules or crusts and sometimes ulcerations.

Diagnosis rests on proof of evidence of the parasite which can be achieved from epilation of hairs or scrapings taken from the skin. The appropriated material is immediately examined under the microscope in the medical lab.

Treatment varies according to the observed clinical stage:

  • Juvenile Localized: can sometimes heal alone and therefore not require any anti-parasite treatment
  • Juvenile Generalized: anti-parasite treatment is required over several months. It is essential to be certain of the diagnosis before beginning the treatment which must be prolonged until full elimination of the symptoms and disappearance of the parasites (verified via microscopic observation).
  • Adult onset: with this type it is essential to search for the root cause leading to the appearance of the parasite. This type is more difficult to treat.

Removal of the affected dog and the dam from the breeding is recommended !