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Acute laryngotracheobronchitis (Croup): Symptoms, Causes, Treatments and Preventions

Acute laryngotracheobronchitis (croup) is a common disease in infants 1 to 3 years old. It is caused by viruses or bacteria inflaming the mucous membrane of the larynx. However, in many cases the cause is not known. Symptoms appear as the airway narrows due to severe swelling of the laryngeal mucosa for some reason. There is a sore throat or a change in voice, a sound when inhaling, a characteristic cough called barking cough, which is said to be similar to the barking of a dog, and difficulty breathing and depression of the chest wall.


Patients with acute laryngotracheobronchitis initially complain of symptoms of upper respiratory tract infection with fever, and a characteristic barking cough sound appears several days later. The cough that occurs at this time is usually not accompanied by phlegm and is characterized by aggravation at night. In rare cases, difficulty breathing due to subglottic edema may occur.


Acute laryngotracheobronchitis is mostly caused by para-influenza virus infection, but there are many cases due to bacterial infection. Inhalation of dust and smoke, excessive use of vocal cords, etc. are also the cause, and infectious diseases such as diphtheria and whooping cough are also contributing factors. Cases caused by diphtheria or whooping cough are called true croup, and cases caused by other causes such as pharyngitis or laryngitis are called pseudo croup.

Diagnosis methods

Diagnosis is possible through symptoms and cervical X-ray examination results, and a steeple sign that looks like a spire in the lower part of the glottis due to edema on the neck X-ray is characteristic.


Reduction of swelling, thinning of secretions, and securing the airways (in case of severe breathing difficulties) are the basics of treatment. Sufficient fluid therapy, humidity control, and oxygen supply are required to dilute the secretions and soften the crusts in the airways. If symptoms continue to worsen despite these treatments, epinephrine spray and high concentrations of corticosteroids should be used. In some cases, endotracheal intubation or tracheostomy may be required. If secondary infection by bacteria is suspected, antibiotics should be used.

Progress and complications

Symptoms may appear suddenly in the middle of the night, or intermittent symptoms may appear 2-3 hours after falling asleep. It usually improves the next morning. If appropriate treatment is initiated after an accurate diagnosis, it can be cured without serious complications, but in rare cases, severe airway obstruction can lead to death.

Prevention methods

It is easy to recur, so it is always necessary to adjust the humidity and temperature appropriately.

Healthy living guide

It is essential to maintain adequate humidity and temperature. In a dry environment, turn on a humidifier to control the humidity. Sudden breathing difficulties at night can be dangerous, so parents should sleep with their babies. In the event of a sudden deterioration of the baby’s condition, parents should take the baby directly to the emergency room.

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