Contributors: Karen Campbell, David Scarff

 Species: Canine   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading


  • One of the most common causes of dermatoses in dogs.
  • Cause: parasitic infection.
  • Signs: mild to severe skin lesions +/- systemic involvement, pruritus.
  • Diagnosis: skin scrapes, identification of parasite, response to treatment.
  • Treatment: effective use of antiparasitic agent.
  • Prognosis: good with effective treatment.
  • Non-parasitic insects can also be implicated.

Presenting Signs

  • Reaction of skin to ectoparasitism varies from trivial to lethal but usually includes inflammation.
  • Pruritus common.
  • Owner lesions.
  • Visualization of parasites.
  • Systemic involvement.



  • Ancylostoma braziliense, Ancylostoma caninum(not seen in UK),Uncinaria stencephala, ancyostomiasis and uncinariasis, hookworm dermatitis.
  • Pelodera strongyloides, pelodera dermatitis (not in UK).
  • Strongyloides stercoralis, strongyloides stercoralis-like infection (one report, not in UK).
  • Anatrichosoma cutaneum, anatrichosomiasis (only in Africa).
  • Schistosomiasis (not in UK).
  • Dracunculusspp, dracunculiasis (not in UK).
  • Dirofilaria immitus, dirofilariasis Canine cardiopulmonary dirofilariasis (rare in UK - not endemic).
  • Taenia crassiceps(one report, USA).
  • Habronemiaspp (one report, USA).
  • Gnathostoma spinigerum(one report, Australia).
  • Lagochiascaris major(one report, Brazil).
  • Rickettsia rickettsii, Rocky mountain spotted fever (USA only).
ProtozoaNon-parasitic mites and insects
  • Environmental mites, egDermatophagoides pteronyssinus,Dermatophagoides farinae.
  • Spiders.
  • Bees.
  • Wasps , see canine facial eosinophilic folliculitis and furunculosis Skin: eosinophilic folliculitis and furunculosis.
  • Hornets.
  • Moths.
  • Ants.
  • Caterpillars.


Presenting Problems

  • Pruritus.
  • Skin lesions.
  • Deep pyoderma/cellulitis.

Client History

  • Severe to mild pruritus.
  • Localized, multifocal or generalized hair loss.
  • Skin lesions on owner.
  • Seasonal occurrence.
  • Skin lesions on in contact animals.
  • Dandruff.
  • Observation of parasites, fleas, lice, ticks,Trombiculaspp, flies, mosquitoes or non-parasitic insects, eg bees, wasps, hornets, ants, caterpillars.
  • Environmental conditions may be suggestive.
  • Head-shaking/aural pruritus.
  • Discharge from ear canal.
  • Malodor.
  • Depression.
  • Housing of patient.

Clinical Signs

  • Skin inflamed and edematous.
  • Excoriation and alopecia as a result of pruritus.
  • Erythema, pustules, papules and crust formation.
  • Hyperpigmentation and lichenification in chronic cases.
  • Scaling.
  • Observation of parasites or other insects.
  • Pinnal scratch reflex.
  • Non-pruritic alopecia.
  • Otitis externa.
  • Pododermatitis.
  • Regional or generalized lymphadenopathy.
  • Nodule formation.
  • Systemic signs.

Diagnostic Investigation

  • Skin scrape Scraping: skin : mites,Pelodora strongyloides.
  • Skin squeezings for demodex.
  • Otoscopic examinationforOtodectes cynotis Otodectes cynotis.
  • Wet paper testfor fleas.
  • Parasiticide therapeutic trial- regression of clinical signs, eg of flea or sarcoptes infestation, once flea control programme instituted.
  • Knott's testfor microfilaria ofDirofilaria spp.
Fecal analysis
  • Hookworm eggs.

Differential Diagnosis




  • Generally good with adequate therapy.

Expected Response to Treatment

  • Resolution of pruritus within days.
  • Skin lesions reducing over weeks.

Reasons for Treatment Failure

  • Incorrect diagnosis.
  • Inadequate treatment by owner.
  • Concurrent disease untreated, eg pyoderma and parasitic infection or parasitic infection secondary to atopy.

Further Reading


Refereed papers

Other sources of information

  • Nesbitt G H & Ackerman L J (1991)Dermatology for the Small Animal Practitioner.Veterinary Learning Systems Co. pp 32 (Excellent table of common parasitic diseases with history, clinical signs and diagnosis).
  • Scott D W, Miller W H & Griffin C E (1995)Muller and Kirk's Small Animal Dermatology.5th edition. Philadelphia: W B Saunders Company. pp 392-468 (Detailed dermatology text book for in-depth reading).

Other Sources of Information