[Use of thermographic methods for estimation of skin prick test results. II. Evaluation of skin prick test results with histamine solutions of different concentration using liquid crystal mixtures].

The aim of the study was to evaluate the usefulness of liquid crystal thermography in interpretation of skin prick tests with selected allergens and different solutions of histamine. The study group consisted of 35 young adults with indications for skin prick tests, and in whom skin tests with different solutions of histamine were also carried out (10 mg of histamine per 1 ml diluted to a concentration of 1:1, 1:10, 1:100). The skin reaction was assessed visually after 15 minutes, measuring flare and wheal diameter and utilizing the liquid crystal thermographic method--assessing the diameter of each colour green, blue, violet. For statistical purposes the area was also calculated. A correlation of each area was performed with the wheal and flare diameter. The area of the skin reaction was largest for both methods using the undiluted solution of histamine, the smallest using the 1:100 dilution. The liquid crystal thermographic method showed larger areas of skin lesions than those using only the visual method by analyzing the size of the wheal and flare. Due to this fact skin tests should be carried out at lest 9 cm apart from each other. The largest correlation was found between diameter of the flare and area of blue colour of the liquid crystal thermographic method (registering the temperature of 34.3 degrees C-36.3 degrees C). Using the thermographic method a joint temperature analysis of the wheal and flare lesions are performed. The results of this study correspond with the earlier, preliminary studies showing the usefulness of the liquid crystal thermographic method in assessing skin reactions to different allergens and histamine solutions.