Otolaryngology Book


Patch Testing

Aka: Patch Testing
  1. See Also
    1. Allergy Test
  2. Indications
    1. Allergic Contact Dermatitis (Type 4 Hypersensitivity)
  3. Efficacy: Evaluating Allergic Contact Dermatitis
    1. Test Sensitivity: 70%
    2. Test Specificity: 70%
  4. Technique
    1. Place drop of each diluted agent in patch test chamber
    2. Apply patch to non-irritated, clean skin of back
    3. Outline each patch outline with pen
    4. Label agent locations on skin and in medical record
    5. Remove patch in 48 hours
    6. Measure skin reaction (see below)
  5. Approach: Interpretation of skin test
    1. Erythema: 1+
    2. Edema or Vesicles involve <50% of patch area: 2+
    3. Edema or Vesicles involve >50% of patch area: 3+
  6. Causes: False positive (consider if multiple positives)
    1. Hyperirritability of skin
    2. Contaminant irritant or allergen on tested skin
    3. Reaction to tape holding patch in place
    4. Irritant Contact Dermatitis
      1. Reaction resolves more quickly than in allergy
      2. Burning sensation contrasted with itching in allergy
      3. Sharply demarcated reaction
  7. References
    1. Mydlarski in Middleton (1998) Allergy, Mosby, p. 1141-2 [PubMed]
    2. Riedl (2003) Am Fam Physician 68:1781-90 [PubMed]

You are currently viewing the original 'fpnotebook.com\legacy' version of this website. Internet Explorer 8.0 and older will automatically be redirected to this legacy version.

If you are using a modern web browser, you may instead navigate to the newer desktop version of fpnotebook. Another, mobile version is also available which should function on both newer and older web browsers.

Please Contact Me as you run across problems with any of these versions on the website.

Navigation Tree