What is croup?Croup is breathing difficulty accompanied by a barking cough. Croup, which is swelling around the voacl cords, is common in infants and children and can have a variety of causes. The symptoms of croup are caused by the swelling and inflammation of the tissues around the larynx and vocal cords. The diameter of the upper airway in young children is narrow
to begin with, so this swelling further reduces the size of the airway. This makes breathing noisier and more labored.
Croup is usually caused by the parainfluenza virus, although there are many other possible viral causes. These include the RS virus, influenza virus type A, rhinovirus, adenovirus, and Coxsackie virus. 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.
Croup primarily affects children younger than 5 years old because their small airways are more susceptible to narrowing when swollen. Adults may simply have a cold with laryngitis, but children may develop croup. Croup is contagious, and is usually spread by airborne infectious droplets sneezed or coughed into the air by infected children. When infectious droplets are inhaled by a healthy child, symptoms can develop in 2 to 3 days. The infection can also be spread by infected mucus deposited on doors, furniture, toys, and other objects. A healthy child can become infected by accidentally touching the infectious mucus and transferring the infection into his/her mouth.