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Mites in Cats, Dogs, etc (Mange, Acariasis, Scabies, Demodicosis)

Updated: Dec 14, 2021


Normal skin anatomy

Mange (demodicosis) refers to an inflammatory, parasitic skin condition of animals that is caused by increased numbers of microscopic mites that are normally present in low numbers in the hair follicles and sebaceous glands of the skin of otherwise healthy animals. The mites cause irritation of the skin, resulting in itching, hair loss, and inflammation and the condition is highly contagious. Though dogs and cats are very susceptible, horses and other domestic animals, as well as wild animals, including humans, can also be infected.


Human demodicosis caused by Demodex folliculorum

There are several types of mange that affect animals, and they include canine scabies (sarcoptic mange), ear mites (otodectic mange), walking dandruff (cheyletiellosis), and trombiculosis.

3D illustration of a Demodex mite
3D illustration of a Demodex mite

However, as a public health consideration, Demodex sp do not cross species barriers, i.e., they are species-specific. Generally, mites occur only on one type of host and a few closely related species, e.g. on canids such as dogs, wolves and foxes, but not on cats; or on cattle and buffaloes but not on sheep or goats, etc.

Species of Mites in livestock and pets

 

All species of mites occur worldwide. Demodex mite infestation usually remains asymptomatic but an important causative agent for many dermatological conditions.

  1. Demodex canis affects dogs (canine follicular mange mite, red mange mite)

  2. Demodex cati affects cats (feline follicular mange mite)

  3. Otodectes cynotis affects mainly cats, seldom dogs; ear mite

  4. Notoedres cati affects cats; feline scabies, cat mange mite

  5. Cheyletiella spp., affects mainly cats, occasionally dogs; walking dandruff

  6. Pneumonyssoides caninum affects dogs; nasal mite

  7. Sarcoptes scabiei var. canis, affects dogs, canine scabies


  1. Demodex bovis (cattle follicle mite)

  2. Chorioptes bovis (chorioptic mange mite)

  3. Psoroptes ovis (cattle scab mite)

  4. Sarcoptes scabiei var. bovis (itch mite, sarcoptic mange mite)


  1. Chorioptes equi (itchy leg mite)

  2. Demodex equi (horse follicle mite)

  3. Psoroptes equi (horse scab mite)

  4. Sarcoptes scabiei, var. equi (the common mange mite)


  1. Chorioptes ovis (chorioptic mange mite)

  2. Psorergates ovis (sheep itch mite)

  3. Psoroptes ovis (sheep scab mite)

  4. Sarcoptes scabiei var. ovis (itch mite, sarcoptic mange mite)


  1. Demodex phylloides (pig follicle mite)

  2. Sarcoptes scabiei var. suis (pig itch mite, sarcoptic mange)


  1. Cnemidocoptes gallinae (depluming itch mite)

  2. Cnemidocoptes mutans (scaly leg mite)

  3. Dermanyssus gallinae (bloodsucking, red poultry mite, red chicken mite)

  4. Epidermoptes bilobatus (scaly skin mite)

  5. Ornithonyssus bursa (bloodsucking, tropical fowl mite); tropical and subtropical climate

  6. Ornithonyssus sylviarum (bloodsucking, northern fowl mite); moderate climate

Man

  1. Demodex folliculorum (commonly localized to the face)

  2. Demodex brevis (commonly found on the neck and chest)

Most people are only carriers of Demodex mites and do not develop clinical symptoms. Human demodicosis can therefore be considered as a multi-factorial disease, influenced by external and/or internal factors.


What are the presenting signs of mange?

 

Mange in dogs and cats can occur at any age presenting either as localized (juvenile-onset) or generalized (adult-onset) demodicosis.

Bulldog with localized demodicosis

Localized (juvenile-onset) demodicosis presents as a focal area of hair loss (alopecia) in puppies less than 12 months of age with severe itchiness. In some instances, cases are due to a genetically linked defect in the immune system, as evidenced by certain breed predispositions. Internal parasites or malnutrition may also predispose younger patients to a proliferation of Demodex spp mites due to immunosuppression. In puppies, Demodex canis is transmitted by the mother within 2 - 3 days after birth causing a low or moderate multiplication with no lesion or localized demodicosis with spontaneous healing. In genetically predisposed puppies, there is moderate multiplication of the Demodex mites causing generalized demodicosis.


Generalized (adult-onset) demodicosis has lesions spread all over the body, with secondary skin bacterial infection (deep pyoderma), and is common in dogs older than 4 years of age.


The first image shows a demodectic mange mite under a microscope. A French Bulldog with generalized demodectic mange, before and after treatment. (Charlie Walker, ThePhotoVet)

The majority of these patients have an underlying condition—typically a disease that suppresses the immune system and predisposes them to demodicosis.


Demodicosis can also be very specifically localized:-


1) Pododemodicosis, affecting feet only with secondary pyoderma

Deep pyoderma pododemodicosis
Deep pyoderma pododemodicosis (Charlie Walker, ThePhotoVet)

2) Otodemodicosis, affecting outer ears causing external ear inflammation and excessive wax production (ceruminous otitis externa), or causing a greasy, mildly alopecic disease which may be pruritic and which predominantly affects the dorsum and head of adults especially by the mite species Demodex injae.

Demodectic otitis
Demodectic otitis (Charlie Walker, ThePhotoVet)

There are three species of Demodex that have been reported as normal commensals in the dog, i.e., Demodex canis (follicular mite), Demodex cornei and Demodex injae. Demodex canis is the most common and is associated with generalized demodicosis and Demodex cornei, once considered a separate species, it is actually a variant of Demodex canis.

What are the predisposing factors for mange?

 

In adult-onset, the following are common predisposing factors:-

  • Serious metabolic disease.

  • Immunosuppressive therapy.

  • Malignant neoplasia

  • Stress.

  • Endoparasite infestation.

  • Deep mycoses

The following conditions are specifically always associated with generalized demodicosis:-

How is mange Diagnosed?

 
1. Client history
  • Localized, multifocal or generalized alopecia.

  • Dandruff.

  • Malodor.

  • Discharge from ears.

  • Lameness.

  • Depression/lethargy.

  • Itchiness (Pruritus.)

2. Clinical signs
  • Hair loss (Alopecia)

  • Secondary bacterial skin disease (pyoderma)

  • Ear disease (Otitis externa)

  • Itchiness (Pruritus.)

  • Scaling.

  • Bacterial infection of paws (Pododermatitis and furunculosis).​


a. Localized demodicosis

  • Focal alopecia - commonly affected face, forelimbs.

  • Redness of skin (erythema) and scaling in alopecic areas (areas with loss of hair).

  • Hyperpigmentation.

  • Secondary superficial skin bacterial infection (pyoderma)

  • Pruritus (Itchiness)


b. Generalized and adult-onset demodicosis

  • Lesions generalized/diffuse .

  • Hair loss.

  • Erythema (redness of the skin).

  • Pruritus (itchiness).

  • Scaling.

  • Crusting.

  • Edema.

  • Hyperpigmentation.

  • Secondary deep pyoderma (skin bacterial infection).

  • Pain.

  • Lymphadenopathy (enlarged lymph nodes).

  • Follicular hyperkeratosis, follicular casts and comedones on close examination.

  • Patches of melanosis in the Yorkshire Terrier.

  • Generalized pustules.

  • Hemorrhagic bullae.

  • Discharging sinuses.

c. Pododemodicosis

Only feet are affected and secondary pyoderma is common. The dog always exhibits lameness due to the painful nature of the condition.

Localized demodicosis (pododemodicosis) - Charlie Walker, ThePhotoVet

d. Demodex injae

  • Mild alopecia on dorsum and head.

  • Seborrhoea oleosa.

  • Pruritus.

e. Otodemodicosis

  • Ceruminous otitis externa.

3. Diagnostic investigation a. Skin scrape:
  • Deep scrapings are taken in 2-3 places after clipping hair and squeezing the skin before scraping.

  • Large numbers of Demodex spp eggs, larvae, nymphs or adults (small numbers are found in normal animals).

b. Hair plucking (Trichography):

  • This is an alternative to skin scrape and is useful in some areas where access is difficult, eg interdigital webs and on the face (used occasionally).


Treatment

 

Localized demodicosis Localized demodicosis may resolve without treatment within 2 months, hence no treatment is required unless secondary infection develops. In breeding dogs, treatment is withheld initially to determine whether the condition will resolve on its own or progress to generalized demodicosis. If progression occurs, the dog should not be used for breeding because it may pass the disease to subsequent generations. Secondary bacterial infection is treated with topical antibacterial shampoo, eg chlorhexidine 0.5%, benzoyl peroxide 2.5%, ethyl lactate 10% +/- systemic antibiotics.


Generalized and adult-onset demodicosis Elimination of concurrent pyoderma is essential to the success of mange treatment.

The most effective treatments are the isoxazoline class of products given at the doses and frequencies licensed to treat flea infestations. Currently, they are not licensed to treat demodicosis with the exception of sarolaner (Simparica) but are licensed to treat other ectoparasites in dogs e.g. fleas and ticks.


What products are in the isoxazoline class?

The Food and Drug Administration (FDA-approved) drugs in this class are

  • Bravecto (fluralaner) tablets for dogs

  • Bravecto (fluralaner) topical solution for cats and dogs

  • Bravecto Plus (fluralaner and moxidectin) topical solution for cats

  • Bravecto 1-month (fluralaner) tablets for dogs

  • Credelio (lotilaner) tablets for dogs and cats

  • Nexgard (afoxolaner) tablets for dogs

  • Simparica (sarolaner) tablets for dogs

  • Simparica Trio (sarolaner, moxidectin and pyrantel) tablets for dogs

  • Revolution Plus (selamectin and sarolaner) topical solution for cats


These products are approved for the treatment and prevention of flea infestations, and the treatment and control of tick infestations. Some are also approved for treatment and control of ear mite infestations and some gastrointestinal parasite infections, and a few are also approved for the prevention of heartworm disease.


Traditional topical treatment

  • Full body clip.

And Bath (weekly) with antiseborrheic shampoo And Antibacterial shampoo, eg benzoyl peroxide 2.5% (for follicular flushing action but can lead to excessive drying or irritation in some individuals), towel dry. And Follow with amitraz (0.05% weekly baths, 10 min contact time, immerse feet for 10 min for pododemodicosis, continue until 2 negative skin scrapes at 3-4 week interval is achieved). Optimum efficacy (80%) is reported at a concentration of 600 mg/ml weekly. Amitraz is contra-indicated in Chihuahua, cats and in diabetic dogs. And Systemic antibiotics, eg cephalexin 20-30 mg/kg BID for at least 3-4 weeks.

  • Use bactericidal antimicrobials for 3-6 weeks or longer if necessary.

Application of amitraz

  • In all but short-coated dogs, clip the entire coat; remove crusts and exudate using antimicrobial shampoos and dry the animal completely before application of amitraz. Apply in a well-ventilated area using protective equipment including gloves. Allow amitraz to air dry.

  • Or Amitraz plus ivermectin: Amitraz used as above plus ivermectin (0.3 mg/kg PO twice-weekly (double dose of ivermectin if still no response to treatment).

  • Or Amitraz plus liquid paraffin: for otodemodicosis or pododemodicosis, topical 0.5 ml amitraz (5%) plus 30 ml liquid paraffin.



Oral treatment

Ivermectin as a prolonged administration is essential. It is continued for one month after the second of two negative skin scrapings taken one month apart; 300-600 ug/kg administered orally once daily.

Ivermectin may cause serious toxic effects in dogs and it is contraindicated in Border Collies, Shetland Sheepdog, Old English Sheepdog and related breeds. Due to potential toxic side-effects, the starting dose rate is at 50 ug/kg and increased at increments of 50 ug/kg daily. Owners are advised to look for signs of ivermectin toxicity and the need to cease treatment if those signs occur. Ivermectin is continued for 60 days beyond multiple negative skin scrapings (3-8 months).​

Milbemycin oxime is less toxic than ivermectin but very expensive; it is administered at 1-2 mg/kg orally once daily. Continued for 30 days beyond multiple negative skin scrapings.


Moxidectin at 200-400 ug/kg administered orally once daily.


Control & Prevention

 
  1. Continue to use isoxazoline product.

  2. Neuter dogs with generalized and adult-onset demodicosis as a predilection to mange is a heritable defect.

  3. The use of isoxazolines for routine flea prevention, in areas where this is desirable, is predicted to prevent demodicosis.

References

 
  • Junquera, P. (2021, July 12). The biology of mites, parasites of dogs, cats, horses & livestock - cattle, sheep, goats, pig, poultry. Retrieved from Parasitipedia Website: https://parasitipedia.net

  • Rather PA, Hassan I. Human demodex mite: the versatile mite of dermatological importance. Indian J Dermatol. 2014;59(1):60-66. doi:10.4103/0019-5154.123498

  • Mueller R S, Rosenkrantz W, Bensignor E, Karaś-Tęcza J, Paterson T, Shipstone M A (2020) Diagnosis and treatment of demodicosis in dogs and cats: Clinical consensus guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 31(1), 5-27 PubMed.

  • Becskei C, Cuppens O & Mahibir S P (2018) Efficacy and safety of sarolaner against generalized demodicosis in dogs in European countries: a non-inferiority study. Vet Dermatol 29 (3), 203-e72 PubMed.

  • Synder D E, Wiseman S & Lilenberg J E (2017) Efficacy of lotilaner (Credelio™), a novel oral isoxazoline against naturally occurring mange mite infestations in dogs caused by Demodex spp. Parasit Vectors 10 (1), 532 PubMed.

  • Beugnet F, Halos L, Larsen D et al (2016) Efficacy of oral afoxolaner for the treatment of canine generalized demodicosis. Parasite 23, 14 PubMed.

  • Six R H, Becskel C, Mazaleski M M et al (2016) Efficacy of sarolaner, a novel oral isoxazoline, against two common mite infestations in dogs: Demodex spp and Otodectes cynotis. Vet Parasitol 222, 62-66 PubMed.

  • Fourie J, Liebenberg J E, Horak I G et al (2015) Efficacy of orally administered fluralaner (Bravecto) or topically applied imidacloprid/moxidectin (Advocate) against generalized demodicosis in dogs. Parasit Vectors 8, 187 PubMed.

  • Shipstone M (2000) Generalised demodicosis in dogs, clinical perspective. Aust Vet J 78 (4), 240-242 PubMed.

  • Chesney C J (1999) Short form of Demodex species mite in the dog - occurrence and measurements. JSAP 40 (2), 58-61 PubMed.

  • Paradis M (1998) Ivermectin in small animal dermatology Part II. Extralabel applications. Comp Cont Ed Prac Vet 20 (4), 459-469 VetMedResource.

  • Kwochka L W, Kunkle G A & Foil C O (1995) The efficacy of amitraz for generalised demodicosis in dogs - a study of two concentrations and frequencies of application. Comp Cont Ed Prac Vet 7 (1), 8-17 VetMedResource.

  • Foley R H (1991) Parasitic mites of dogs and cats. Comp Cont Ed Prac Vet 13 (5), 783-800 VetMedResource.

  • Smith E K (1988) How to detect common skin mites through skin scrapings. Vet Med 83 (2), 165-170 VetMedResource.

  • Miller W H Jr, Griffin C E & Campbell KL (2013) Canine demodicosis. In: Muller and Kirk's Small Animal Dermatology 7th edition. W B Saunders, Philadelphia. pp 304-313 (Detailed dermatology textbook for in-depth reading.)

  • Kwochka K W (1993) Demodicosis. In: Current Veterinary Dermatology - the Science and Art of Therapy. Eds. C E Griffin, K W Kwochka & J M MacDonald. St Louis: Mosby Year Book. pp 72-84. (Excellent diagnostic criteria chart and treatment plan.)




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