"Generalized demodicosis" is a term used to describe a skin condition in which a tiny mite called Demodex proliferates and causes widespread skin problems.
Full definition
Evaluation of the efficacy and safety of imidocloprid 10 % plus moxidectin 2.5 % spot - on in the treatment
of generalized demodicosis in dogs: results of a European field study.
Relapse is always a possibility
with generalized demodicosis as there is no easy way to confirm that every mite has been killed, but most dogs that relapse do so within a six to 12 month period from the time they appear to have been cured.
This product was recently evaluated as a topical treatment
for generalized demodicosis in a small study involving 16 dogs older than 1 year of age.16 Dogs were divided into two equal groups and treated with the spot - on at the proposed minimum dose rate (20 mg / kg of both metaflumizone and amitraz, 0.133 ml / kg) on days 0, 28, and 56 or days 0, 14, 28, 42, 56, and 70.
Relapse is always a possibility with
generalized demodicosis as there is no easy way to confirm that every mite has been killed but most dogs that relapse do so within a 6 - 12 month period from the time they appear to have achieved cure.
As the puppy grows up and his immune system matures, the immune system tends to naturally regain control of their mite infestation; in fact, 30 - 50 % of dogs under age one year recover spontaneously from
generalized demodicosis without any form of treatment.
Moxidectin — Few studies are available, but moxidectin (Cydectin injectable — Fort Dodge) given orally at 400 µg / kg / day can be effective in treating
generalized demodicosis.10, 27,28 Moxidectin can be started at a lower dose and then gradually increased to 400 µg / kg / day similar to ivermectin, as outlined above.
We consider a dog to have
generalized demodicosis if the condition involves the feet, an entire body region, or several sites; is spreading; or has persisted for at least six months.
Although this moxidectin spot - on appears to be equally effective when compared with milbemycin oxime in the treatment of
generalized demodicosis using the criteria of this study, more long - term studies with stricter evidence for parasitologic cure are needed to corroborate these findings.
This type of mange is usually seen in dogs that are between 3 and 12 moths, with the mites passed from mother to puppy (referred to as Juvenile on -
set generalized Demodicosis).
Adult
onset generalized demodicosis is not usually associated with genetic predisposition but sometimes as a result of other conditions such as cancer, liver disease, kidney disease or steroid use and therefore may be more difficult to treat successfully.
Additional diagnostic tests may be required for adult dogs that have
severe generalized demodicosis to discover the underlying cause of the weak immune system.
This presentation may occur by itself or as part of generalized demodicosis.5
generalized demodicosis appears to occur more frequently in Aussies with a family history of autoimmune disease, so it is possible these diseases have some form of immune system dysfunction in common.
Because generalized demodicosis in Aussies is often found in families that also have autoimmune disease, breeders should consider it related to those diseases and part of a single health and breeding issue.
It seems like this would be a simple task since localized demodicosis classically involves several round facial bald spots and
generalized demodicosis involves a bald scaly entire dog; still, reality does not always fit into neat categories in this way.
As the puppy grows up and his or her immune system matures, the immune system tend to naturally regain control of their mite infestation; in fact, 30 - 50 % of dogs under age 1 year recover spontaneously
from generalized demodicosis without any form of treatment.
Table 5: Macrocyclic Lactone Dosages
for Generalized Demodicosis in Dogs The ease of oral administration compared with dips makes macrocyclic lactones the first line of therapy for many dermatologists (Table 5).
Thus, patients need to be monitored for side effects during the first several weeks to months of therapy.10 The pour - on formulation of ivermectin is not effective in
treating generalized demodicosis.10
This is quite a contrast to
generalized demodicosis as described below so it is important to be able to distinguish localized from generalized disease.
Ivermectin — For
generalized demodicosis, the injectable form of ivermectin is given orally at a dose of 300 to 600 µg / kg / day.10, 12 The aqueous formulations may be more palatable than are the propylene glycol - based products.
The use of a spot - on is an exciting concept, but more critically evaluated trials are needed to substantiate this drug's efficacy in the long - term control of
generalized demodicosis.
Clinical signs and microscopic examination of skin scrapings are used to guide treatment for
generalized demodicosis.
When using macrocyclic lactones for
generalized demodicosis, the owner must understand its extralabel use and potential for side effects.
This spot - on product was evaluated in the treatment of
generalized demodicosis through a multicenter, randomized, blinded field trial during the registration process in Europe.30 Another group of dogs with generalized demodicosis was treated with daily milbemycin oxime and served as the control group.
Unfortunately, the use of macrocyclic lactones for
generalized demodicosis is considered extralabel, and there is no antidote to the potentially serious and life - threatening side effects.
Table 1: Treatment Summary for
Generalized Demodicosis in Dogs Generalized demodicosis can be one of the most frustrating skin diseases you will ever treat (Table 1).
Efficacy of 1.25 % amitraz solution in the treatment of
generalized demodicosis (eight cases) and sarcoptic mange (five cases) in dogs.
Signs of
generalized demodicosis may include patches that appear on the head, legs and trunk and can eventually spread all over the dog's body.
Generalized demodicosis and generalized dermatophytosis also may resemble ischemic dermatopathy.
Generalized demodicosis has similar signs, but they're widespread and more severe.
Pododemodicosis may be part of
generalized demodicosis or be the only lesions present.
When it is part of
generalized demodicosis, pododemodicosis may persist despite appropriate therapy, even if resolution of other affected areas is noted.
Localized demodicosis commonly develops between 3 and 6 months of age and generally resolves without treatment in 6 to 8 weeks.2, 4 Dogs with a history of localized demodicosis may be predisposed to develop demodicosis later in life, particularly immunocompromised animals.3
Generalized demodicosis may begin as many small, localized lesions that progress to cover a large body area.
Several areas (4 to 6 sites) should be sampled in patients with
generalized demodicosis; in patients with localized demodicosis, samples should be collected from each lesion.
Generalized demodicosis is treated with oral or topical medication depending on the individual case.