Qualizza Rosanna, Megali Raffaella, Incorvaia Cristoforo
Allergy Service, Istituti Clinici di Perfezionamento, Milano, Milan, Italy.
Iran J Allergy Asthma Immunol. 2009 Sep;8(3):161-4.
Toxocara canis is an intestinal nematode affecting dogs and cats that causes human infestations by ingestion of embryonated eggs excreted in dogs' faeces. Humans are transport hosts, in whom the larvae do not develop to adult worms, but may migrate to various tissues and organs, and survive for several years, giving rise to several clinical symptoms, which include allergy-like presentations. We report three cases presenting as dermatitis, rhinitis, asthma, and conjunctivitis which were diagnosed and unsuccessfully treated as allergy. The correct diagnosis was established after detecting anti-Toxocara antibodies by Western blotting. All clinical symptoms showed improvement after starting treatment with mebendazole and subsequent courses of the antiparasitic drug resulted in full recovery. This suggests the possible role of Toxocara canis in inducing chronic symptoms of allergic type. This is particularly important for asthma, where it has been demonstrated that Toxocara canis infection causes allergic inflammation in the lungs associated with bronchial hyperreactivity. On the other hand, in our patients with asthma and with dermatitis the positive results from allergy tests were a confounding factor in delaying the correct diagnosis, which was finally obtained by the detection of antibodies to Toxocara canis.
犬弓首蛔虫是一种寄生于犬猫肠道的线虫，可通过摄入犬粪便中排出的感染性虫卵导致人类感染。人类是转运宿主，幼虫在人体内不会发育为成虫，但可能迁移至各种组织和器官，并存活数年，引发多种临床症状，包括类似过敏的表现。我们报告了3例表现为皮炎、鼻炎、哮喘和结膜炎的病例，这些病例最初被诊断为过敏并接受治疗但未成功。通过蛋白质印迹法检测到抗犬弓首蛔虫抗体后才确诊。开始使用甲苯达唑治疗后，所有临床症状均有所改善，后续使用抗寄生虫药物治疗后完全康复。这表明犬弓首蛔虫可能在诱发慢性过敏型症状中起作用。这对于哮喘尤为重要，已有研究表明犬弓首蛔虫感染会导致肺部过敏性炎症并伴有支气管高反应性。另一方面，在我们的哮喘和皮炎患者中，过敏试验的阳性结果是延迟正确诊断的一个混杂因素，最终通过检测犬弓首蛔虫抗体才得以确诊。
