Skin pathologies in our patients can be persistent and unsightly. They can also often defy strictly conventional approaches. This can be especially true of parasitic invasions, of which the most common are demodex and sarcoptes.
Also known as demodicosis, colloquially called “red mange”, demodectic mange is caused by a microscopic mite of the Demodex genus. A normal inhabitant of canine skin, this mite’s 20 to 35-day life cycle from birth to death takes place on an animal host. Demodex mites are transferred through direct contact from the bitch to her puppies during their fi rst week of life. When there is disruption of natural balance, these mites can proliferate out of control, causing skin disease.
Symptoms include localized or diffuse alopecia, erythema, and comedones associated with papular and pustular dermatitis. It is often associated with folliculitis and furunculosis due to secondary opportunistic bacterial and/or mycotic infections, such as Malassezia, when there are changes in the cutaneous microenvironment and/or alterations of host defense mechanisms. Factors implicated in the appearance of clinical signs of demodectic mange include genetic predisposition, malnutrition, immuno-suppressive conditions, such as stress in puppies, and/or vaccination. It should be noted that heavy metal toxicity suppresses the immune system and opens the door to chronic conditions. The vaccine preservative thimerosal (a mercury additive) is immuno-suppressive and may be a contributing factor to the appearance of demodectic mange in post-weaning puppies, and perhaps older pets. In older dogs, neoplasia, steroid use, diabetes, hyperadrenocorticism and metabolic disease have been implicated.
A 1997 study showed that a significant alteration in the CD4+/CD8+ ratio may be implicated in the pathogenesis of canine demodicosis. Dogs also exhibit signifi cantly lower values of other hematological parameters – hemoglobin, total erythrocytes, total leukocytes, lymphocytes, monocytes and neutrophils. Premature apoptosis of peripheral blood leukocytes may be implicated in the immuno-suppression of dogs with demodicosis. In addition, mural folliculitis is a consistent lesion of clinically active canine demodicosis, characterized by infi ltration of the follicular epithelium by cytotoxic T lymphocytes.
Localized demodicosis, usually in juvenile dogs, occurs as isolated scaly bald patches, usually on the face but occasionally elsewhere. It is considered common and the majority of cases resolve with no treatment of any kind. Localized disease does not involve more than two body regions. (One or two spots on the face and a leg would still qualify as localized even though the spots are not close together.) Localized disease involves no more than four spots total on the dog.
Generalized demodicosis can be very difficult to treat, and requires persistent intervention and dedicated owners, since it is multifactorial and often complicated by concurrent infections.
Demodectic pododermatitis is very resistant, confi ned to the paws, and often accompanied by bacterial infections, as the foot is the last stronghold of the mite. Old English Sheepdogs and Shar Peis tend to get severe forms of this condition.
This type is caused by the deeply burrowing mite, Sarcoptes scabiei. It is extremely contagious between dogs, and can be transmitted to people. It is the mange most people picture when the think of a “mangy dog”. Dogs are highly pruritic, with progressive hair loss, reddened skin and scabbing, especially on ear flaps, eyes, elbows, feet and chest. It is often diffi cult to detect on skin scrapings, so it is often better to treat it on clinical signs, even in the presence of a negative scraping.
• Dipping – Paramite dip (a discontinued organophosphate) and lime-sulfur dips were mainstays of treatment for sarcoptes, but of very limited value in demodecosis. Generally, anything that will clear demodex will control sarcoptes.
• Goodwinol ointment – used for many decades in our practice, since approximately 10% of localized demodicosis cases will progress to generalized demodicosis, often accompanied by lymphadenopathy. Thus, we are in favor of improving the general health of the skin and immune system. Total resolution is usually less than three months.
• Ivermectin – a broad spectrum, inexpensive parasiticide. It must be used with caution in dogs with the MDR gene, such as sight hounds and herding breeds. Ivermectin is injected or given orally at .05 mg/kg to 3 mg/kg, depending on toleration. We have had success giving ivermectin two to three times weekly, though the literature suggests daily dosing.
• Moxidectin (Advantage Multi®) – can be used to treat demodicosis and is often effective if used weekly.
• Amitraz (Mitaban) Dip – this is an old therapy we have not used in many years, but the best efficacy was at double strength applied weekly. It can be quite toxic, particularly in small dogs. Preventic (amitraz) collars have had some success, but they must be changed often (about every four weeks). • Doramectin – given as injections or orally 0.6 mg/kg every one to two weeks, or milbemycin (Interceptor) 1 mg/kg to 2 mg/kg every two weeks. • Milbemycin oxime (Interceptor) can be an effective but expensive approach to generalized demodicosis (0.52 mg/ kg to 3.8 mg/kg of body weight, q 24 hr). May be used in dogs with genetic sensitivity to ivermectin (herding breeds, primarily, carrying the MDR gene). Some dogs require concurrent dipping.
Physiological stress is an important factor in the severity of demodectic mange, so consider diet and nutrition, internal parasite control, judicious use of vaccines, and spaying females to minimize the hormonal shift that causes mites to proliferate. Avoid steroids, as they suppress the immune response. Both endogenous and exogenous steroids will cause significant involution of the thymus gland. Which brings us to our complementary therapies.
• Thymus extracts come from the thymus glands from bovine, ovine or porcine sources. Basic and clinical research has been conducted on these since the early 1900s. The results are encouraging and demonstrate the effectiveness of oral or injectable thymic fractions. Thymus extracts have been shown to modulate the production, maturation and activation of T lymphocytes and macrophages, and to stimulate conversion of immature thymocytes (T6 cells) to non-dedicated T cells (T3 cells) in human bone marrow. Auto-sanguis (auto-hemo therapy) will help with modulating the immune system, and with reducing the antigen/antibody reaction to the self tissues, down-regulating chronic inflammation. This is one of our mainstays in the treatment of immunological challenges.
• Beneficial classic homeopathics include Sulfur, Silicea and Psorinum. It is best to consult a qualified homeopath to make sure the remedy fits the case. Several complex homeopathics are available from from Heel. For example, Psorinoheel, containing miasmatic nosodes, as well as Cutis comp, Coenzyme comp, BHI Skin, and Echinacea comp forte (for concurrent pyoderma). Regrettably, these are no longer available in the US, but they can still be sourced from Europe.
• Also recommended would be an immune-stimulating glandular complex compound, and supplements that target gut/liver function. We routinely use blue-green algae as a bio-modulator, along with with Gluta-DMG (Vetri-Science), Probiotic 123 (Pure Encapsulations), Food Grade Enzymes (Ritezyme), Colostrum/IGG, et.al. A badly afflicted older dog with demodex benefited from the algae compound in addition to his ivermectin and Preventic collar, despite having concurrent ehrlichiosis.
• Other adjunctive care:
o Vitamin E (natural), up to 1,600 IU/day in divided doses.
o Omega-3 fatty acids can reduce the baseline inflammation.
o Lemongrass and cedar oil have been reported as effective therapeutics, as an adjunct to immune support.
o Herbals and supplements to fight bacterial infections and strengthen the immune system include echinacea, arabinogalactans, olive leaf, neem leaf, colostrum and pau d’arco.
o Also useful for infection is colloidal silver, which can be used topically and orally.
o Virgin coconut oil shampoo at high concentration (70% to 80%) eliminated Sarcoptes spp. and Demodex spp. by about the tenth week of treatment
o We have also been intrigued with the use of Manuka hydrosol formulas, which have antibacterial, antiinflammatory, anti-yeast and reparative qualities.
o Neem oil is helpful for both demodectic and sarcoptic mange. Bathe three times weekly with 1 oz to 2 oz of neem oil per 16 oz of shampoo.
Caswell JL, Yager JA, Parker WM, Moore PF. “A prospective study of the immunophenotype and temporal changes in the histologic lesions of canine demodicosis.” Vet Pathol, 1997: Jul;34(4):279-87.
Chen TA, Hill PB. “The biology of Malassezia organisms and their ability to induce immune responses and skin disease”. Vet Derm., 2005: 16:4–26.
Ghubash R. “Parasitic Miticidal Therapy”. Clin Tech Small Anim Pract., 2006: 21:135–44.
Gothe R. “Demodicosis of dogs – a factorial disease?” Berl Munch Tierarztl Wochenschr, 1989: Sep 1;102(9):293-7.
Kouttab et al. “Thymomodulin: Biological Properties and Clinical Applications.” Med. Oncol. and Tumor Pharmacother, 1989: 6, 5-9.
Shipstone M. “Generalised demodecosis in dogs, clinical perspective.” Aust Vet J., 2000: 78:240–42
Singh SK, Dimri U, Sharma MC, Sharma B, Saxena M. “Determination Of CD4+ And CD8+ T Cells In The Peripheral Blood Of Dogs With Demodicosis”. Parasitology, 2010: Nov;137(13):1921-4.
Singh SK. Dimri U, Sharma MC, Swarup D, Sharma B, Pandey HO, Kumari P. “The role of apoptosis in immunosuppression of dogs with demodicosis”. Vet Immunol Immunopathol, 2011 Dec 15;144(3-4):487-92. doi:10.1016/j.vetimm.2011.08.008. Epub 2011 Aug 17.
Skotnicki AB. “Therapeutic application of calf thymus extract (TFX)”. Medical Oncology & Tumor Pharmacotherapy, 1989: 6(1):31.
Skotnicki AB, Dabrowska-Bernstein BK, Babrowski MP, Gorski A, Czarnecki J, Aleksandrowicz J. “Biological properties and clinical use of calf thymus extract TFX-Polfa”. Thymic Hormones and Lymphokines, ed. Goldstein, AL. Plenum Press, 1984: 545.