Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow, Poland.
Med Phys. 2011 Feb;38(2):765-72. doi: 10.1118/1.3533940.
The allergic response is commonly identified and assessed by skin testing. The usual method to quantify skin reactions is to mark wheal and erythema regions and assess the surfaces affected by the reactions; however, subjective interpretation of the outcome may cause errors. Skin thermography supplemented by a mathematical model based on the pathophysiology of heat generation was evaluated as a novel, objective, and sensitive indicator of the skin prick test result.
TH measurements were performed simultaneously with routine skin prick tests for 24 patients. Eight allergens and control (histamine) were examined. Thermographic images of both forearms were acquired every 70 s from 0 to 910 s after skin prick and analyzed with the use of dedicated software. The introduction of potential allergens and histamine at sites on the skin induces a complex sequence of events known as the local inflammatory response. The crucial steps of the process have been considered in the model. In the model, the authors assumed that the reaction takes place in the thin skin layer and that histamine is the principal mediator of the allergic reaction. Histamine penetrates the skin and binds to receptors of nearby capillaries and venules. The engorged vessels are, in turn, responsible for skin redness and an increase in skin temperature.
The model parameters were determined by fitting the analytical solutions to the spatiotemporal distributions of the differences between measured and baseline temperatures. The model reproduces experimental data very well. The coefficient of determination ranged from 0.805 to 0.995. Seven model parameters were tested to find the optimal marker of the intensity and kinetics of the allergic reaction. The parameter which quantifies a release of histamine after allergen injection has appeared to be the best indicator of the allergen-induced response. The parameter correlates with the routine assessment based on wheal and erythema areas (correlation coefficient = 0.98).
It was demonstrated that the thermographic measurements supplemented by the mathematical model offer a new approach to the quantification of allergen-induced skin reactions. Despite the applied simplifications, the proposed model reflected properly the mechanism of heat generation during skin prick test. Moreover, the continuous recording of the skin temperature represents an additional possibility to investigate the mechanism of the allergic reaction.
过敏反应通常通过皮肤测试来识别和评估。定量皮肤反应的常用方法是标记风团和红斑区域，并评估受反应影响的表面；然而，结果的主观解释可能会导致误差。皮肤热成像辅以基于发热病理生理学的数学模型被评估为一种新的、客观的、敏感的皮肤点刺试验结果指标。
对 24 例患者同时进行 TH 测量和常规皮肤点刺试验。检查了 8 种过敏原和对照（组氨酸）。从皮肤点刺后 0 到 910 秒，每 70 秒采集一次前臂的热像图，并使用专用软件进行分析。潜在过敏原和组胺在皮肤部位的引入会引起一系列被称为局部炎症反应的复杂事件。该模型考虑了该过程的关键步骤。在该模型中，作者假设反应发生在薄的皮肤层中，并且组氨酸是过敏反应的主要介质。组氨酸渗透皮肤并与附近毛细血管和小静脉的受体结合。充血的血管反过来导致皮肤发红和皮肤温度升高。
通过将分析解拟合到测量和基线温度之间的时空分布差异，确定模型参数。该模型很好地再现了实验数据。决定系数范围从 0.805 到 0.995。测试了七个模型参数以找到过敏反应强度和动力学的最佳标记物。定量过敏原注射后组胺释放的参数似乎是过敏原诱导反应的最佳指标。该参数与基于风团和红斑面积的常规评估相关（相关系数=0.98）。
证明了热成像测量辅以数学模型为定量过敏原诱导的皮肤反应提供了一种新方法。尽管应用了简化，但所提出的模型正确地反映了皮肤点刺试验过程中发热的机制。此外，皮肤温度的连续记录为研究过敏反应机制提供了另一种可能性。
