Diagnostic Considerations
Exercise-induced urticaria, also known as exercise-induced anaphylaxis, is a rare and unrelated condition to exercise-induced asthma (EIA). Only 500-1000 cases of exercise-induced urticaria have been reported in the literature. In this condition, there is an early stage of exercise-related fatigue and itchiness, followed by early onset of urticaria and angioedema, which is initially mild. [18]
If progression occurs in exercise-induced urticaria, there is choking, stridor, nausea, vomiting, and even hypotension. A late stage that is marked by headache may also occur. As implied by the alternative name of anaphylaxis, exercise-induced urticaria can be life threatening; however, this can be prevented by exercise modification or avoidance of certain conditions.
Professionals caring for athletes must also keep a high index of suspicion for vocal cord dysfunction, which manifests as stridor with exercise due to paradoxical contraction of the vocal cords with inspiration and does not respond to the same treatment. The highly driven, high-performing adolescent athlete, especially the female athlete, is at high risk for this condition. Vocal cord dysfunction can be evaluated via laryngoscopy after an exercise challenge (see Laryngoscopy and Challenge Tests).
The physician, trainer, or other medical staff must always consider bronchospasm in athletes with the previously described complaints. A high index of suspicion diminishes the possibility of missed diagnoses. A thorough knowledge of the differential diagnosis (see Differentials) and how to work up the possibilities are also important (see Workup).
Other problems to be considered in patients with EIA include deconditioning syndrome, seasonal asthma, and upper airway obstruction.
Differential Diagnoses
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Pathogenesis of asthma. Antigen presentation by the dendritic cell with the lymphocyte and cytokine response leading to airway inflammation and asthma symptoms.
