Masqueraders in clinical allergy: laryngeal dysfunction causing dyspnea.

The allergist may be called upon to evaluate patients with dyspnea that is labeled "refractory asthma." In some patients, the site of origin of their dyspnea is the larynx. The diagnosis of laryngeal disorders requires a thorough understanding of the normal function of the laryngeal anatomy and physiology. Some patients with asthma may have a component of their airway obstruction in the larynx and large airways. Paradoxical vocal cord motion occurs when the true vocal cords approximate during inspiration, and although severe subjective dyspnea may occur, in most cases there is no evidence of hypoxia, hemoglobin desaturation, or an abnormality of the arterial-alveolar oxygen gradient. Provocative tests with methacholine are negative in this group of patients. Patients with PVCM are usually female and may have an affiliation with the medical profession. Many have psychologic difficulties, and the foundation of treatment is speech therapy and psychotherapy if indicated. Other disorders that may produce dyspnea from laryngeal dysfunction include Meige syndrome, abductor spastic dysphonia, and laryngospasm. Recognition of these disorders will expedite timely, accurate diagnosis and treatment.