Canis ISSN: 2398-2942

Skin: flea bite hypersensitivity

Synonym(s): Flea allergic dermatitis

Contributor(s): Rosanna Marsella, Richard Squires

Introduction

  • A pruritic, papular dermatitis, often of the dorsal lumbosacral region due to sensitization to flea salivary allergens.
  • The most common cause of hypersensitive skin disease.
  • Cause:Ctenocephalides felis, via allergens presented when flea bites.
  • Signs: pruritus, tapeworm segments, flea bites on owner, pyotraumatic dermatitis, superficial pyoderma.
  • Diagnosis: clinical signs, hematology, histopathology, serology.
  • Treatment: flea control and possibly glucocorticoids.
  • Prognosis: excellent, provided flea control maintained.

Pathogenesis

Predisposing factors

General
  • Contact with fleas.
  • Multi-animal households.
  • Contact with free-ranging cats.
  • History of exposure to the tapewormDipylidium caninum Dipylidium caninum , for which the flea is the intermediate host.
  • Moving from a cold to a warm area, ie from a low exposure to fleas to high exposure.

Pathophysiology

  • Hypersensitivity is triggered by the flea bite.
  • Most dogs show an immediate-type hypersensitivity reaction, a wheal or papule develops within 15-30 min. This persists for up to 72 hours. Crusts develop secondarily due to self trauma.
  • Many dogs also show a delayed reaction.
  • Up to 30% of dogs only show a delayed reaction.
  • Skin biopsies also show a cutaneous basophil reaction and late phase IgE-mediated reactions.
  • Continually exposed dogs may become partially immunologically tolerant, but it is rare to achieve natural desensitization.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lee S E et al (1999) Putative salivary allergens of the cat flea, Ctenocephalides felis. Vet Immunol Immunopathol 69 (2-4), 229-237 PubMed.
  • Marsella R (1999) Advances in flea control. Vet Clin North Am 29 (6), 1407-1424 PubMed.
  • Bevier D E (1997) Flea allergy dermatitis testing breakthrough. Canine Pract 22 (2/3), 49-50 VetMedResource.
  • McKeon S E, Opdebeeck J P (1994) IgG and IgE antibodies against antigens of the cat flea, Ctenocephalides felis, in sera of allergic and non-allergic dogs. Int J Parasitol 24 (2), 259-263 PubMed.
  • Stopler R, Opdebeeck J P (1994) Flea allergy dermatitis in dogs diagnosed by intradermal skin tests. Res Vet Sci 57 (1), 21-27 PubMed.
  • Dryden M W & Blakemore J C (1989) A review of flea allergy dermatitis in the dog and cat. Comp Anim Prac 19 (6 & 7), 10-17 VetMedResource.

Other sources of information

  • MacDonald J M (1993)Flea Allergy Dermatitis and Flea Control.In:Current Veterinary Dermatology.Eds. C E Griffinet alSt Louis: Mosby Year Book p 57.
  • Scott D W, Miller W H & Griffin C ECanine Flea Bite Hypersensitivity.In: Muller and Kirk'sSmall Animal Dermatology.5th edn. Philadelphia: Saunders. pp 536-539.


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