Reproducibility of skin sensitivity using a quantitative skin prick test

Area of Science:

• Allergy and Immunology
• Dermatology
• Pharmacology

Background:

• Quantitative skin prick testing (SPT) is used to assess allergic skin responses.
• Reproducibility of SPT methods is crucial for accurate clinical assessment.
• Endpoint titration (EPT) and histamine equivalent reaction (HER) are common SPT quantification methods.

Purpose of the Study:

• To evaluate the reproducibility of repeated quantitative skin prick test titrations.
• To compare the reproducibility of endpoint titration versus histamine equivalent reaction.
• To determine the clinical applicability of quantitative SPT for assessing mast cell releasability.

Main Methods:

• Seven asthmatic patients underwent repeated SPT (2-4 times within 6 weeks).
• Skin sensitivity was measured using endpoint titration and histamine equivalent reaction (HER).
• Histamine dihydrochloride concentrations of 1 and 10 mg/ml were used for HER.

Main Results:

• Histamine equivalent reaction demonstrated significantly higher reproducibility than endpoint titration.
• HER using 10 mg/ml histamine dihydrochloride showed a coefficient of variation <10%.
• Repeated testing with 10 mg/ml histamine showed deviations <0.5 log step, indicating high constancy.

Conclusions:

• Quantitative SPT, particularly HER, offers a reproducible method for assessing skin sensitivity.
• HER is a reliable tool for evaluating changes in skin mast cell releasability.
• This method has clinical applications in monitoring pharmacological or immunotherapy effects in asthma.