Canis ISSN: 2398-2942

Skin: intradermal test

Contributor(s): David Scarff, Catherine Fraser

Overview

  • Identify potentially important allergens in order to start immunotherapy once a diagnosis of atopy Skin: atopy has been made.

Sampling

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Tests

Methodologies

  • Skin testing is performed with dogs in lateral recumbency usually with the use of sedation, eg medetomidine Medetomidine.
  • An area approximately 15x15 cm over the lateral trunk is clipped.
  • Injection sites are marked with a felt-tip marker.
  • 0.05 ml of each of a panel of allergens is injected into the dermis with histamine and saline used as positive and negative controls respectively.
  • Injection sites are examined 15 min later for immediate reaction Intradermal skin testing , and at 24-48 hours for delayed reaction.

Availability

  • Intradermal skin testing is available by referral to a veterinary dermatologist.
    Intradermal skin test panels are available but testing and interpretation should only be undertaken by experienced practitioner.

Validity

Sensitivity

  • 66-90%.
  • A positive intradermal skin test indicates that animal has skin sensitizing antibody.
    A positive test does not necessarily mean that the allergen is clinically significant in that animal.

Specificity

  • Completely negative results are usually because the tentative diagnosis of atopy was incorrect.

Technique (intrinsic) limitations

  • False-positives: may occur if very irritable, inflamed or traumatized test site, eg with pyoderma Skin: mucocutaneous pyoderma.
  • False-negatives: if drug interference, inherent host factors, eg serious internal disease, testing at the wrong time of year.

Technician (extrinsic) limitations

  • Poor skin test technique may give false-negative or false-positive results.
  • Irritant allergens may give false-positive results.
  • Insufficient allergenic principle, eg outdated extract may give false-negative results.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Mueller R S, Bettenay S V & Tideman L (2000) Aero-allergens in canine atopic dermatitis in southeastern Australia based on 1000 intradermal skin tests. Aust Vet J 78, 392-399.
  • Codner E C & Lessard P (1993) Comparison of intradermal allergy test and enzyme-linked immunosorbent assay in dogs with allergic skin disease. JAVMA 202, 739.

Other sources of information

  • Moriello K A & Mason I S (1995) Eds Handbook of Small Animal Dermatology.1st edn. Pergamon. pp 33-36. (Concise step-by-step procedure.)
  • Scott D W, Miller W H, Griffin C E (1995) Eds Muller and Kirk's Small Animal Dermatology. 5th edn. Philadelphia: WB Saunders Co. (Concise step-by-step procedure).
  • Sousa C A & Norton A L (1990) Advances in methodology for diagnosis of allergic skin disease. Vet Clin North Am Small Anim Pract 20, 1419-1427.
  • Reedy L M & Miller W H (1989) Allergic skin diseases of dogs and cats.1st edn. Philadelphia: W B Saunders. pp 81-109. (Detailed procedure and interpretation.)


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