Croup (laryngotracheobronchitis) is an inflammation of the windpipe (trachea) and voice box (larynx) typically caused by a contagious viral infection that causes cough, a loud squeaking noise (stridor), and sometimes difficulty with breathing in (inspiration).
Croup is caused by a viral infection that leads to swelling of the lining of the airways, particularly the area just below the voice box (larynx). Parainfluenza virus is the most common cause, but croup can be caused by other viruses, such as the respiratory syncytial virus or an influenza virus. Although croup is most common in the fall and winter, it occurs throughout the year. Croup primarily affects children 6 months to 3 years of age, although it occasionally affects those younger or older. Croup caused by an influenza virus may be particularly severe and may occur in a broader age range of children. The infection usually is spread by breathing in airborne droplets containing viruses or by having contact with objects contaminated by these droplets. Most children experience only a single episode of croup, but a few have repeated episodes (spasmodic croup) caused by viral infections that gradually decrease in frequency and severity.
Symptoms and Diagnosis
Croup usually starts with symptoms of a cold—runny nose, sneezing, mild fever, and some coughing. Then the child develops hoarseness and a frequent, unusual-sounding cough, which is described as brassy or barking. Croup ranges widely in its severity. Sometimes swelling of the airway causes difficulty breathing, which is most noticeable on breathing in (inspiration). In severe croup, there may be a loud squeaking noise (stridor) heard with each inspiration. About 50% of children have a fever. All symptoms are typically much worse at night and may awaken the child from sleep. The child's condition often improves in the morning and worsens again the next night.
A doctor distinguishes croup by its characteristic symptoms, especially the sound of the cough. The worst of the symptoms usually lasts 3 to 5 days, and the cough continues but changes to a looser-sounding cough. This change can cause concern for parents who think the infection has moved to the chest. However, it is the normal progression of the illness.
X-rays of the neck and chest help the doctor make a definitive diagnosis.
If a child develops a croupy breathing pattern, the parents should contact the doctor because children with croup can become very ill very quickly. In general, a child who is mildly ill with croup may be cared for at home and usually recovers in 3 to 4 days. The child should be made comfortable, given plenty of fluids, and allowed to rest because fatigue and crying can worsen the condition. Home humidifying devices (for example, cool-mist vaporizers or humidifiers) may reduce drying of the upper airways and ease breathing. The humidity can be raised quickly by running a hot shower to steam up the bathroom. Carrying the child outside to breathe cold night air also may open the airways significantly.
For sicker children, the doctor may recommend a single dose of a corticosteroid to prevent worsening of symptoms. Children with continuous croup should be seen immediately by a doctor who will likely recommend corticosteroids and may hospitalize the child for observation and care. Children with increasing or continuing difficulty in breathing, rapid heart rate, fatigue, or bluish skin discoloration need to be given oxygen, as well as fluids by vein. Doctors usually treat the child with epinephrine given in a nebulizer and corticosteroids given by mouth or injection. These drugs help shrink swollen tissue in the airways. Children who improve with these treatments may be sent home, although children with more severe cases should remain in the hospital. Antibiotics are used only in the rare situation when a child with croup also develops a bacterial infection. Rarely, a ventilator is needed. Fortunately, the vast majority of children with croup recover completely.
Last full review/revision February 2009 by Anand D. Kantak, MD; John T. McBride, MD