感冒後嗅覚障害

摘要

Postviral olfactory disorder (PVOD) is one of the most common causes of persistent olfactory loss. It predominantly affects middle-aged and elder women. The patients usually notice loss of smell while they have a cold, but visit ENT clinics only after several weeks/months, realizing that the olfactory impairment persists despite the resolution of cold symptoms. The pathophysiology of PVOD is thought to be sensorineural damage of the neuroepithelium and/or central olfactory tracts, either by direct viral insult or by immune reaction against the virus. Endoscopic and radiological examinations reveal no abnormalities, and are useful to differentiate PVOD from other causes of olfactory impairment. Zinc, Kampo medicines, steroids, vitamins, and cerebral metabolic activators have been used singly or in combination for the treatment of PVOD. Recent studies have also reported the usefulness of olfactory-training for the treatment of PVOD. Relatively long periods (＞1 year) are usually necessary for the significant improvement of olfactory function.%感冒後嗅覚障害は，上気道のウィルス感染罹患後に上気道炎症状が消失したあとも嗅覚障害が持続する状態である.発症は中高年齢の女性に多く，嗅神経上皮および中枢嗅覚伝導路の傷害による神柽性嗅覚障害と考えられている.内視鏡検査，画像検査では異常を認めず，上気道炎罹患後に嗅覚低下を自覚したという病歴が本疾患の診断の決め手となる.基準嗅力検査では中等症以上が大半で高度低下，脱失例が半分以上を占める.治療は本邦では亜鉛製剤，漢方製剤，ステロイド点鼻および内服，ビタミン製剤，代謝改善剤などが使用されている.また嗅覚トレーニングが回復に有効との報告もある.機能回復には長期間(1年以上)かかることが多い.