Millqvist E
Allergy Centre, Sahlgrenska University Hospital, Gothenburg, Sweden.
Allergy. 2000 Jun;55(6):546-50.
A group of patients with asthma-like symptoms and sensitivity to chemical irritants, but without bronchial obstruction, has been found among subjects referred for suspected asthma. They have no well-defined diagnosis, and no objective diagnostic method has previously been available. These patients are more sensitive to inhaled capsaicin than are patients with asthma or healthy controls. The aim was to study cough and other capsaicin-induced symptoms and to test the effect of a drug (lidocaine) that inhibits nerve transmission in sensory nerves.
Twelve patients were provoked with three different concentrations of inhaled capsaicin solutions in a randomized, double-blind order. They all had asthma-like symptoms and were sensitive to chemical irritants, but had no IgE-mediated allergy or demonstrable bronchial obstruction. Before the provocations, the patients inhaled lidocaine or placebo (saline), also in a double-blind, randomized order. The results were expressed as the number of coughs and scores of various symptoms.
The patients reacted in a dose-dependent way with cough, airway, and eye symptoms, which were significantly reduced after preinhalation of lidocaine.
A drug that inhibits transmission in sensory nerves successfully blocked the number of coughs and other symptoms provoked by inhalation of capsaicin. This indicates that the mechanisms underlying chemical sensitivity in these patients may originate in the sensory nervous system, and we call this condition "sensory hyperreactivity".
在因疑似哮喘而转诊的患者中，发现了一组有哮喘样症状且对化学刺激物敏感但无支气管阻塞的患者。他们没有明确的诊断，且此前没有客观的诊断方法。这些患者比哮喘患者或健康对照对吸入辣椒素更敏感。目的是研究咳嗽及其他辣椒素诱发的症状，并测试一种抑制感觉神经中神经传导的药物（利多卡因）的效果。
12名患者以随机、双盲的顺序吸入三种不同浓度的辣椒素溶液进行激发试验。他们都有哮喘样症状且对化学刺激物敏感，但无IgE介导的过敏反应或可证实的支气管阻塞。在激发试验前，患者也以双盲、随机的顺序吸入利多卡因或安慰剂（生理盐水）。结果以咳嗽次数和各种症状的评分表示。
患者对咳嗽、气道和眼部症状呈剂量依赖性反应，吸入利多卡因后这些症状明显减轻。
一种抑制感觉神经传导的药物成功减少了吸入辣椒素诱发的咳嗽次数和其他症状。这表明这些患者化学敏感性的潜在机制可能源于感觉神经系统，我们将这种情况称为“感觉性高反应性”。
