Viral Croup: A Current Perspective

Alexander K.C. Leung, MBBS, FRCPC, FRCP (UK & Irel), FRCPCH; James D. Kellner, MD, FRCPC; David W. Johnson, MD, FRCPC


J Pediatr Health Care. 2004;18(6) 

In This Article

Etiology and Epidemiology

Parainfluenza virus accounts for more than two thirds of cases of viral croup, with type 1 and 2 responsible for the majority of cases (Malhotra & Krilov, 2001; Peltola et al., 2002). Other etiologic agents include influenza virus, respiratory syncytial virus, metapneumovirus, adenovirus, rhinovirus, enterovirus and, rarely, measles virus and herpes simplex virus (Ewig, 2002; McIntosh & McAdam, 2004). When croup is caused by an influenza virus, the clinical picture is usually more severe than that caused by a parainfluenza virus (Peltola et al., 2002).

Croup accounts for approximately 15% of respiratory tract disease seen in the pediatric age group (Cherry, 2004). The condition is most common between the ages of 6 months and 3 years but can occur in children as young as 3 months and as old as 15 years of age; the peak incidence occurs during the second year of life (Thomas & Friedland, 1998). The male to female ratio is approximately 3 to 2 (Knutson & Aring, 2004). The condition is most prevalent in the fall and winter months (Ewig, 2002; Knutson & Aring, 2004). Transmission is by droplets and/or direct contact (Cressman & Myer, 1994).


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.