Croup is a respiratory infection in children that produces characteristic symptoms and signs. The infection mainly involves the vocal cords (larynx) and windpipe (trachea), and to a lesser extent the upper airways of the lungs (bronchi). The majority of the symptoms come from inflammation of the larynx. Usually, croup is caused by a viral infection. It may be caused by many different viruses, including those responsible for colds and the flu. Less commonly, croup can be caused by a bacterial infection.

Signs and symptoms associated with croup include fever, sore throat, hoarseness, and cough. The cough has been described as having a "barking" sound that may be associated with a harsh, raspy sound during inspiration, known as stridor. Other possible symptoms can include impaired voice, agitation, fast breathing, noisy breathing, fatigue, runny nose, and stuffy nose.

Causes of croup

Many different viruses cause croup, including influenza, adenovirus, measles, and parainfluenza RSV. Occasionally, a bacterial infection causes croup. Acid reflux, allergies, and inhaling irritants.