Exercise-Induced Laryngeal Obstruction (EILO) versus Exercise-Induced Asthma in Athletes: A Narrative Review of Differentiation and Management

Abstract

Background: Exercise-induced laryngeal obstruction (EILO) and exercise-induced bronchoconstriction (EIB), the clinical hallmark of exercise-induced asthma, are the two dominant medical explanations for exertional dyspnoea in athletes. They are physiologically distinct yet routinely confused, and EILO is frequently mislabelled and mistreated as refractory or difficult-to-control asthma.

Aim: To critically compare EILO and exercise-induced asthma in athletes and to synthesise current evidence on their differentiation and clinical management.

Material and methods: Narrative review of peer-reviewed clinical studies, consensus documents and reviews addressing the pathophysiology, epidemiology, diagnosis and treatment of EILO and EIB in athletic and adolescent populations.

Results: EILO is a mechanical, predominantly supraglottic, inspiratory upper-airway collapse that peaks at maximal effort and resolves within minutes, whereas EIB is an inflammatory, expiratory lower-airway obstruction that typically peaks after exercise. Continuous laryngoscopy during exercise is the diagnostic gold standard for EILO, while EIB requires objective bronchoprovocation. Symptoms and questionnaires cannot reliably separate the two conditions, which frequently coexist. EILO responds to non-pharmacological strategies and does not respond to asthma medication or inhaled ipratropium, whereas EIB is managed with inhaled corticosteroids and beta-2 agonists within anti-doping limits.

Conclusions: Persistent exertional dyspnoea that fails to respond to asthma therapy should prompt objective testing for EILO rather than escalation of asthma treatment. Awareness, objective diagnosis and condition-specific management are essential to avoid medical error and impaired performance.