These mites (Demodex canis) thrive only on their specific hosts (dogs). The transmission of these mites from mother to pup is normal. But some dogs develop an overgrowth of these mites, a condition called demodicosis, or demodectic mange. WHAT YOU MAY NOTE. Signs of demodicosis can. Abstract. Demodicosis is a common canine ectoparasitosis. Recognising the clinical presentation, identifying the parasite and choosing the most appropriate.
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The mite Demodex canis is an ectoparasite and a normal inhabitant of canine hair follicles and sebaceous glands of the skin.
This disease is most commonly caused by D. Demodicosis can be classified as localized or generalized, with a juvenile or adult onset. Prognosis and treatment options vary, depending on the form of the disease. Criteria differentiating each form have not been uniformly established. Generalized demodicosis is a more serious disease. The juvenile-onset form typically presents before the dog reaches 1 year of age.
Patients with localized demodicosis may not need to be treated. If treatment is recommended, topical therapy e. To identify patients with disease that will progress to the generalized form, it is important not to use systemic miticidal therapy to treat patients with localized disease. It is thought that the juvenile-onset generalized form develops as a result of an inherited immune dysfunction; therefore, owners of patients with this form of disease should be advised that their dogs should not be bred.
Adult-onset demodicosis is usually seen in adult dogs aged 4 years or older. If an underlying cause cannot be determined at diagnosis, monitoring should continue throughout treatment. The inability to identify and manage the underlying cause may decrease the likelihood of a successful outcome. Underlying causes include diabetes mellitus, hyperadrenocorticism either naturally occurring or iatrogenic due to glucocorticoid administrationneoplasia, treatment with immunosuppressive agents, hypothyroidism, heartworm disease, intestinal parasitism, and leishmaniasis.
A minimum database i. Additional tests for hyperadrenocorticism and thyroid function as well as radiography and ultrasonography may also be warranted, depending on the case. Many patients present with circular areas of alopecia. Occasionally, patients present inn a diffuse area of thin ddogs.
If untreated, these patients may also develop hyperpigmentation and lichenification along with increased body odor due to excess sebum production from sebaceous glands associated with hair follicles.
Draining tracts may also form due to rupturing hair follicles. The severity of clinical signs e. Demodicosis is seen most often in purebred dogs 1,2 and puppies and young dogs up to 18 months of age. To find mites, it is necessary to obtain multiple, deep doggs scrapings from affected areas. Proper sample collection techniques are essential when scraping for Demodex mites.
A spatula or 10 scalpel blade can be used to collect the samples. Scraping should be deep enough to produce capillary bleeding dovs squeezing the area being scraped; this forces mites deep in the hair follicle to the surface. Microscopically, fusiform eggs, six-legged larvae, eight-legged nymphs, or eight-legged adult mites dead or alive can be seen FIGURE 3.
Ideally, for each scraping site, the number of mites or at least an estimated percentage, including dead and living mites in each life stage should be recorded in the patient’s medical record BOX 1.
Trichography may be used to search for adult mites attached to the hair shaft. This procedure involves plucking some hairs in the direction of hair growth and placing them in mineral oil on a glass slide for microscopic examination. Because trichography is not as reliable as skin scraping for diagnosing demodicosis, 2,3,6 it should complement and not replace skin scraping.
Trichography may be helpful for yielding mites when collecting samples from areas of the skin that are difficult to squeeze or scrape, such as interdigital and periocular areas.
A punch biopsy may be needed if skin-scraping results are negative and the index of suspicion for demodicosis is high. The biopsy may be necessary in patients with thick skin e. Demodixosis general health of patients diagnosed with generalized demodicosis should be evaluated and managed before miticidal therapy is instituted.
Treatment options depend on many factors, such as patient history, extent and location of clinical signs, and the patient’s breed. Before therapy for demodicosis is initiated, the veterinarian should ask the owner to list any medications or supplements that the dog is receiving. The client’s ability and willingness to administer a therapy should be discussed when choosing a therapy, as should financial considerations.
Client compliance is extremely important to the success of treatment. Patients with demodicosis should not be treated with glucocorticoid therapy or other types of immunosuppressive drugs. Bathing with a benzoyl peroxide shampoo before dipping may be beneficial for its keratolytic effect and follicular flushing activity.
Clipping medium- and long-haired dogs may facilitate dipping by allowing better contact between the skin and the dip solution. Mitaban dips are applied topically and licensed for use every 14 days. The solution should be prepared as labeled dilute 1 bottle [ The person applying the dip should wear gloves and protective clothing, and the patient should be treated in a well-ventilated area.
Dip should not be toweled off; the patient should be allowed to dry naturally.
Patients receiving other monoamine oxidase inhibitors, such dogd amitriptyline and selegiline, should not receive this treatment. After the first treatment, patients may experience lethargy and sedation for 24 to 48 hours. Other adverse effects include bradycardia, hypothermia, and hyperglycemia.
Metaflumizone plus amitraz spot-on Promeris for Dogs, Fort Dodge Animal Health is labeled to kill and control Demodex spp mites on dogs. These dogs were not followed up after discontinuation of therapy. Treatment using the products discussed below is considered off-label. Adverse effects of avermectins and milbemycins are dos and include mydriasis, hypersalivation, lethargy, ataxia, seizure, coma, and death. Ivermectin Ivomec injection for cattle and swine, Merial is a common first-choice treatment of many dermatologists 2,3,5 because it is easy to administer and reasonably priced.
An injectable form of ivermectin is administered orally. Because of potential adverse effects on the central nervous system, this therapy should not be used in ivermectin-sensitive breeds i. Although milbemycin oxime Interceptor, Novartis Animal Health can be expensive for treating large-breed dogs, it may improve client compliance through its ease of administration i.
The dosage is 0. The findings suggest that sensitive-breed dogs treated with milbemycin need to be monitored carefully because they may experience ataxia.
Demodicosis in Dogs
However, these dogs were not followed up after remission. If the patient has secondary pyoderma, oral antibiotics may be needed until complete resolution of lesions, which is assessed at the first 4-week recheck appointment. Patients with deep pyoderma require longer treatment until complete resolution. Antibacterial shampoos such as benzoyl peroxide and demodicoss can be beneficial for treating patients with secondary pyoderma. Shampooing can be done weekly or more often, as necessary.
If an antibacterial shampoo is used with an amitraz dip, the patient should not be shampooed between dip treatments. Reducing stress and providing adequate nutrition can also improve success in managing demodicosis. Feeding the dog a complete and balanced diet is important.
Fatty-acid supplementation may also have a possible benefit. After treatment begins, patients should be checked every 4 to 6 weeks until two vogs negative skin-scraping results are obtained.
At each visit, a physical examination should be performed and skin scrapings taken from the areas that were scraped initially and from any new lesions.
The results should be recorded and compared with those from the previous visit. By the first recheck examination, very few, if any, Demodex mites in immature stages should be seen. Ideally, the percentage of dead adult mites should be higher than the percentage demoeicosis live adult mites.
This indicates that the owner is being compliant and the therapy is working. Treatment should be continued for 4 weeks after the second negative skin-scraping result. Once treatment is stopped, the patient is considered to be in remission.
Rechecks and skin scrapings should be performed every 3 to 4 months for the next year. Relapses can occur within this time frame, so owners need to observe their dogs carefully for evidence of disease.
One year after a second negative skin-scraping result and no recurrence of disease, the patient can finally be declared cured. Treatment can fail, and some patients may need some type of therapy for the rest of their lives. Pododemodicosis is demodjcosis difficult to cure and carries a poor prognosis. Clients need to be well informed of the challenges, time, and expense involved in treating canine demodicosis.
It is important that they also have a good understanding of the disease. Patients often appear clinically normal after 1 to 2 months of therapy, but it is vital that owners do not stop the treatment because mites may still be present and a relapse is likely without the full treatment.
Clients also need to understand that if their dog has been diagnosed with adult-onset demodicosis but an underlying condition has not been found, an underlying disease could still be predisposing the dog to demodicosis. Owners of intact dogs with generalized demodicosis should be advised ln spay or neuter their dogs 1 deodicosis of the hereditary predisposition to develop the disease and 2 to eliminate the stress of estrus, which can exacerbate the disease.
Treatment of canine demodicosis can be challenging, and therapeutic options depend on many factors, including type of demodicosis localized or generalized, juvenile or adult onsetpatient history and breed, underlying causes, and client considerations. Although obtaining a parasitologic cure using currently available treatments may take a long time, treating secondary infections or underlying conditions can greatly improve the patient’s comfort and prognosis.
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