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Updated: Jul 16, 2026
Precision Implementation of Minimal Erythema Dose (MED) Testing to Assess Individual Variation in Human Inflammatory Response
Published on: October 3, 2019
Objective evaluation of skin prick test reactions using digital photography
Rosaly Vieira dos Santos1, Richard G Titus, Hermênio Cavalcante Lima
1Immunodermatology and Clinical Immunology Research Center at Federal University of Paraná, Paraná, Brazil.
Background:
The skin prick test has been used worldwide to determine IgE-mediated hypersensitivity. However, the most current method to record this reaction has problems with accuracy and precision.
Objective:
To demonstrate a new approach to measure the skin prick reaction and its kinetics with precision.
Methods:
The skin prick test was induced using histamine or Dermatophagoides pteronyssinus antigen in 80 volunteers aged 4 and 67 years who had different skin colors. Digital photographs were obtained at 0, 3, 5, 10, 15 and 20 min. The mean wheal and erythema area as well as the erythema intensity were determined using Adobe Photoshop software. The accuracy and precision of this approach were also evaluated.
Results:
The digital photographic analysis measured the wheal and erythema sizes independent of the antigen or skin color with precision. In addition, a new variable of this test, the skin erythema intensity, could be determined objectively using the chromaticity of reflected light.
Conclusions:
Digital photographic analysis is a precise and objective method to evaluate the skin prick test reaction, which can be used independent of the patient's skin color in clinical or research settings.
