大约五分之一的40岁及以上的人以及三分之一的80岁及以上的人报告出现嗅觉和味觉障碍。这些障碍会影响生活质量，以及识别烟雾和毒素的能力。嗅觉和味觉障碍可能是痴呆症或帕金森病的早期症状，并与增加的死亡率相关。功能障碍可能明显可见，也可能隐晦发展。虽然有筛查问卷可供使用，但许多患者对自身障碍缺乏意识。大多数嗅觉和味觉障碍是由鼻窦疾病引起的，但也可能由吸烟、药物、头部外伤、神经退行性疾病、酒精依赖以及其他较少见的疾病引起。鉴别诊断应指导评估，并包括鼻前窥镜检查、口腔、头部和颅神经的检查。进一步的调查通常是不必要的，但鼻内窥镜检查和鼻窦的计算机断层扫描可能会有所帮助。如果存在异常的神经检查结果，或者怀疑存在创伤或肿瘤，应进行头部磁共振成像检查。对于难以治疗的病例或与嗅觉或味觉功能障碍相关的生活质量较差的患者，应进行嗅觉测试。当可逆原因得到治疗时，嗅觉和味觉障碍可能会得到缓解，但当其原因是创伤、年龄或神经退行性疾病时，改善的可能性较小。嗅觉训练是一种自我管理的正念曝露疗法，可以改善嗅觉功能。医生应鼓励患者确保烟雾和其他警报器正常运作，并遵守食物过期日期。

Disorders of smell and taste are reported by approximately one-fifth of people 40 years and older, and one-third of people 80 years and older. These disorders affect quality of life and the ability to identify smoke and toxins. Smell and taste disorders can be early signs of dementia or Parkinson disease and are associated with increased mortality. Dysfunction may be apparent or may develop insidiously. Screening questionnaires are available, but many patients are unaware of their disorder. Most smell and taste disorders are due to sinonasal disease but also could be caused by smoking, medications, head trauma, neurodegenerative disease, alcohol dependence, or less common conditions. The differential diagnosis should guide the evaluation and include anterior rhinoscopy and an examination of the oral cavity, head, and cranial nerves. Further investigation is often unnecessary, but nasal endoscopy and computed tomography of the sinuses may be helpful. Magnetic resonance imaging of the head with contrast should be performed if there is an abnormal neurologic examination finding or if trauma or a tumor is suspected. Olfactory testing is indicated in refractory cases or for patients with poor quality of life and disease associated with smell or taste dysfunction. Smell and taste disorders may resolve when reversible causes are treated, but improvement is less likely when they are due to trauma, age, or neurodegenerative disease. Olfactory training is a self-administered mindful exposure therapy that may improve olfactory function. Physicians should encourage patients to ensure that smoke and other alarms are operational and to adhere to food expiration dates.