What is croup?

A condition that mostly affects babies and young children between the ages of 6 months and 3 to 5 years of age, croup is a viral infection that results in swelling of the voice box (larynx), vocal cords, bronchial tubes (bronchi or upper airways of the lungs) and windpipe (trachea), irritating the upper airways.

Swelling results in a narrowing of the airways and leads to breathing difficulties (which can develop a high-pitched whistling sound called stridor - this can be heard while breathing in) and a cough resembling that of a dog’s bark (some liken the sound to the bark of a seal as well). A little one’s voice may also become hoarse and raspy too.

Viruses which are responsible for the common cold or flu (parainfluenza viruses), as well as others such as respiratory syncytial virus (RSV) and adenovirus, generally also cause croup. The majority of instances are caused by a virus. The most common germ which affects young children is RSV (respiratory syncytial virus).

Croup can, however, on occasion, be caused by bacteria (bacterial tracheitis – a secondary bacterial infection of the trachea) or inhaled irritants resulting in allergies. Normally, if symptoms of croup do not resolve, a doctor can distinguish between the viral and bacterial infection in order to recommend effective treatment. Viral and bacterial infections are not typically treated in the same way.

Babies and young children are most vulnerable to croup, with infections typically peaking around 24 months of age. Older children and adults can become infected as well. Incidences of this viral infection tend to be higher around the autumn (fall) and winter months of the year.

Croup is generally not considered a very serious viral infection and is more often than not, mild. For the most part, an infection runs its course and can be comfortably treated at home. More severe instances can occur and will then require medical intervention.

Illustration showing the difference between healthy airways and ones affected by croup.

NEXT Causes and types of croup

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