Causes of Croup
Causes of croup are primarily viral in nature, with inflammation of the larynx and trachea resulting in the hallmark symptoms of barking cough and stridor. Although rare, bacterial infections or allergic reactions can also trigger croup. The vast majority of cases are due to respiratory viruses.
Viral Infections
The most common viral causes include:
Parainfluenza virus types 1 and 2: These are responsible for most cases of croup, particularly in autumn and early winter.
Respiratory syncytial virus (RSV): Known for causing bronchiolitis, RSV can also contribute to croup, especially in infants.
Influenza virus: Seasonal flu viruses can lead to more severe forms of croup.
Adenovirus and rhinovirus: These viruses can sometimes cause croup-like symptoms in toddlers and older children.
These viruses transmit through respiratory droplets and by touching infected surfaces. Children in childcare or school settings face higher exposure risk.
Immature Immune Systems
Young children are more susceptible to developing croup because their airways are smaller and their immune systems are still developing. Even a small amount of inflammation in a young child’s trachea can cause significant breathing difficulty.
Environmental Factors | Causes of Croup
Croup may also be exacerbated by:
Exposure to cold air, which can irritate the airways
Dry indoor heating, which dries out the respiratory tract and increases vulnerability to infection
Allergens or pollutants: Rarely, croup-like symptoms may be triggered by inhaling smoke or strong fumes
Non-Viral Causes
Less commonly, bacterial infections such as bacterial tracheitis or epiglottitis can cause similar symptoms to croup but are typically more severe and require hospitalisation.
Recurrent Croup
Some children experience repeated episodes of croup, often triggered by viral infections or allergic reactions. Recurrent croup may require further investigation to rule out structural airway abnormalities or chronic conditions like asthma.
In conclusion, causes of croup are mainly viral, with environmental and anatomical factors influencing susceptibility and severity. Understanding these causes helps parents take preventive measures and seek early treatment.
