Appropriate diagnosis and management of persistent eczematous conditions such as contact dermatitis are common challenges for the allergist. Patch testing attempts to reproduce the allergic reaction on the normal skin on the upper back of the patient.
Patch Testing for Proper Diagnosis of Contact Dermatitis
Contact allergen skin testing is a simple and objective scientific method available to physicians to augment the diagnostic process. Often, the patch test response is the crucial piece of information that allows for the early identification of the offending allergen(s) and confirmation of a diagnosis of Allergic Contact Dermatitis (ACD) and/or Irritant Contact Dermatitis (ICD). Once a diagnosis is achieved, the patient can then take appropriate action to avoid exposure to the allergen and, if possible, substitute non-allergenic agents.
The patches are applied and subsequently removed after 48 hours. The patch site continues to be read after 72 – 96 hours.
The diagnostic value of patch testing depends upon the choice of the test substance, the vehicle, the concentration, results in interpretation, and patient counseling. Patch tests are comprised of materials that occur in the home, work, and/or recreational environment.