Diseases & Conditions
Croup (laryngotracheobronchitis) is a contagious viral infection of the upper airways that causes cough and sometimes difficulty breathing, especially breathing in.
Croup is a viral infection that causes 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 is more likely to occur in children between the ages of 3 and 7. The disease is usually spread by breathing in airborne droplets containing viruses or by having contact with objects contaminated by these droplets.
Symptoms and Diagnosis
Croup usually starts with symptoms of a cold—runny nose, sneezing, mild fever, and some coughing. Then the child develops a frequent, unusual-sounding cough, which is described as "brassy" or barking. 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. 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.
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 may also open the airways significantly—something parents often discover when the child's breathing returns to normal by the time they arrive at the hospital.
Children who do not respond to these measures need to be taken to the hospital. Children with increasing or continuing difficulty in breathing, rapid heart rate, fatigue, or bluish skin discoloration need to be hospitalized. In the hospital, oxygen is given when levels of oxygen in the blood are low. Doctors usually treat the child with epinephrine Some Trade Names ADRENALIN 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 2003
Source: The Merck Manual Home Edition