Is Croup Cough contagious?
Croup is very much contagious, and is primarily spread through the airborne medium - that is the infectious droplets which get sneezed out or coughed out into the air by other infected children. A healthy child could develop symptoms in 2-3 days after inhaling these droplets. The infection also spreads through common objects shared with infected children because infected mucus gets deposited on doors, toys, furniture, and many other objects. A healthy child may get infected through accidental transfer of the infectious mucus to his/her mouth. So essentially, croups is indeed contagious and therefore appropriate precautions can protect a child from contracting croup.
It's absolutely imperative that the child's breathing is monitored closely especially at night time or during naps to check for difficulty in breathing. The narrowing of the air passages and the difficulty in breathing associated with it are the most crucial concerns. Should the child, at any point, have difficulty in breathing, fever in excess of 103o F or feel restless, the doctor should immediately be notified.
Are multiple instances of croup possible for a child?
Yes. Since croup is caused not by just one virus but by multiple ones with many subtypes of each virus - RSV (respiratory syncytial virus), parainfluenza, adenovirus, and the flu virus (influenza). As a result, for each type of virus, a child may get croup another time.
NOTE: if a child has a tendency to get croup a little too often - there is a possibility that the child is suffering from spasmodic croup which is acute spasmodic laryngitis. This may be caused by a variety of factors - allergies or reflux or viruses. Children who have spasmodic croup may have breathing trouble but wouldn't have fever and have recovery time as short as just a few hours.
If it's contagious, how to prevent it?
No vaccines or medications are in existence today which may prevent croup cough (barring perhaps the flu vaccine) but a decrease in exposure to sick people can probably decrease the chance of infection. Promoting basic practices like proper hygiene and avoiding food sharing etc also help in preventing infection.