CROUP
Croup is characterized by a loud cough that resembles the barking of a seal and may be accompanied by fast or difficult breathing and sometimes a grunting noise or wheezing while breathing. At first, a child may have cold symptoms like a stuffy or runny nose for a few days and may also have fever. As the upper airway (the lining of the windpipe and the voice box) becomes progressively inflamed and swollen, the child may become hoarse, with a harsh, barking cough.
If the upper airway becomes swollen to the point where it is partially blocked off, it becomes even more difficult for a child to breathe. This happens with severe croup. With severe croup, there may be a high-pitched or squeaking noise (stridor) when breathing in. A child will tend to breathe very fast, and the stomach or the skin between the child's ribs may seem to pull in during breathing. The child may also appear pale or bluish around the mouth because he is not getting enough oxygen.
Symptoms of croup often worsen at night and when the child is upset or crying. In addition to the effects on the upper airway, the infections that cause croup can result in inflammation further down the airway, including the bronchi (breathing tubes) and the lungs.
The term croup does not refer to a single illness, but rather a group of conditions involving inflammation of the upper airway that leads to a characteristic barking cough, particularly when a child is crying. Most croup is caused by viruses, but similar symptoms may occasionally be caused by bacteria or an allergic reaction. The viruses most commonly involved are parainfluenza virus (accounting for most cases), adenovirus, respiratory syncytial virus, influenza, and measles.
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bronchiolitis
Bronchiolitis is a common illness of the respiratory tract caused by a respiratory infection that affects the tiny airways, called the bronchioles, that lead to the lungs. As these airways become inflamed, they swell and fill with mucus, making it difficult for a child to breathe.
The first symptoms of bronchiolitis are usually the same as those of a common cold:
stuffiness
runny nose
mild cough
These symptoms last a day or 2 and are followed by worsening of the cough and the appearance of wheezes (high-pitched whistling noises when breathing out).
Sometimes more severe respiratory difficulties gradually develop, marked by:
rapid, shallow breathing (60 to 80 times a minute)
a rapid heartbeat
drawing in of the neck and chest with each breath, known as retractions
flaring of the nostrils
irritability, with difficulty sleeping and signs of fatigue
The child may also have a fever, a poor appetite, and may vomit after coughing. Less commonly, young infants, especially those born prematurely, may have episodes where they briefly stop breathing (this is called apnea) before developing other symptoms.
In severe cases, symptoms may worsen quickly. A child with severe bronchiolitis may tire from the work of breathing and have poor air movement in and out of the lungs, due to the clogging of the small airways. The skin can turn blue (called cyanosis), which is especially noticeable in the lips and fingernails. The child can also become dehydrated from working harder to breathe, vomiting, and taking in less during feedings.
Contagiousness
The infections that cause bronchiolitis are contagious.