What is the most common virus that causes laryngitis?

Most Common Viral Cause of Laryngitis

Parainfluenza viruses are the most common causative agents of acute laryngitis in children. 1

Primary Viral Etiology

• Parainfluenza viruses represent the predominant viral cause of acute laryngitis (croup), particularly in children aged 0.5 to 3 years 1

• In documented cases of infectious subglottic laryngitis, parainfluenza virus was isolated in 60% of cases, making it by far the most frequently identified pathogen 2

• Other respiratory viruses can also cause laryngitis, though less commonly than parainfluenza 2, 3

Clinical Context and Diagnosis

• Acute laryngitis typically presents with dry, barking cough and inspiratory difficulty with wheezing 1

• The diagnosis is clinical, based on characteristic symptoms rather than laboratory confirmation 1, 4

• Viral infections of the airways lead to narrowing of the laryngeal lumen in the subglottic region in approximately 3% of children 4

Important Distinction: Laryngitis vs. Pharyngitis

• The evidence provided primarily addresses pharyngitis (throat infection), where respiratory viruses including adenovirus, influenza, parainfluenza, rhinovirus, and RSV are common causes 5, 6

• However, for laryngitis specifically (voice box infection), the evidence clearly identifies parainfluenza as the dominant pathogen 1, 2

Common Pitfall to Avoid

• Do not confuse laryngitis with pharyngitis—they involve different anatomical sites and have different predominant viral causes 1, 4

• While multiple respiratory viruses can affect the larynx, parainfluenza viruses have been specifically documented as the leading cause in clinical studies 1, 2