Croup

Alternative names:

acute laryngotracheobronchitis; viral croup

Definition:

A condition of breathing difficulty caused by infection, inflammation, and swelling of the upper airway (larynx, trachea, and bronchus).

Croup is characterized by a "barking" cough (sometimes described as a hoarse cough, or as a seal-bark cough); hoarseness (laryngitis); noisy, high-pitched breathing sounds when inhaling (stridor); and increasing difficulty in breathing.

Causes, incidence, and risk factors:

Croup is usually caused by viral infection (parainfluenza virus, respiratory syncytial virus (RSV), and influenza viruses A and B) which is present in the air around others with the infection. A bacterial infection leading to croup is most often caused by Hemophilus influenza (epiglotitis, a life-threatening infection). Croup can also be caused by allergies, trauma, or foreign bodies (toys, peanuts, other small objects) in the airway. Croup most often occurs in children between 6 months and 3 years of age.

The recognizable barking cough and noisy breathing (stridor) is caused by swelling in the upper airway (larynx, trachea, and bronchi). The child's breathing becomes more difficult and requires increasing physical effort. The child may be physically tired but is unable to rest because of the increased breathing effort.

The child may be restless, have a fever, and be working hard to keep breathing. Extra effort to breathe may be noticed as wider opening of the nasal openings during inhalation (nasal flaring); increased use of the muscles in the neck and chest; and unwillingness to lie down, rest, eat, or drink. In severe cases the child's lips and fingers may turn blue (cyanosis), indicating inadequate oxygen supply.

See also epiglottitis.