Although newborns are not usually prone to wheezing, according to Children's Memorial Hospital, first-time wheezing is quite common between the ages of 2 and 5 months. Resembling a whistle, wheezing is usually heard when an infant exhales, and is a symptom of many childhood illnesses and conditions. Understanding the most common causes of wheezing in infants can help parents determine treatment and prevention options.
Bronchiolitis and RSV
Bronchiolitis is a common viral infection caused by RSV, or the respiratory syncytial virus. Because an infant's airways are naturally small, the infection can easily cause the airway to swell and make breathing difficult. In addition to wheezing when exhaling, other symptoms include rapid breathing, a cough and fever. Supportive care can provide symptom relief while the illness runs its course.
Early Asthma
Asthma is a condition that causes the airways to swell, tighten and produce large amounts of mucus. Wheezing is one of several symptoms that may indicate asthma in a young child. According to MayoClinic.com, other symptoms include rapid breathing, frequent coughing that occurs after activity, and a family history of allergies, asthma or eczema.
Unfortunately, diagnosing infants is difficult because lung functioning tests require a level of cooperation that is challenging for children under the age of 5. According to Children's Memorial Hospital, "recurrent episodes of wheezing has been defined by the National Asthma Education and Prevention Program Expert Panel as more than three episodes of wheezing in the past year that lasted more than one day and affected sleep." Doctors usually treat wheezing that resembles asthma with asthma medications. Parents should note that their baby does not necessarily have asthma just because asthma medications help relieve breathing difficulty. Many children who experience infant wheezing "grow out of it," and do not develop asthma.
Infant Reflux
Infant gastroesophageal reflux disease, or GERD, occurs when stomach acids regurgitate into the stomach due to a weak or malfunctioning valve between the stomach and the esophagus. According to AskDrSears.com, symptoms of infant GERD often include colicky or irritable behavior, frequent spit-up or vomiting, and unexplained bouts of wheezing or asthma-like symptoms.
Less Common Causes
While asthma, reflux and RSV are the most common explanations for infant wheezing, there are also a few less likely culprits. Wheezing is more common in premature infants with extremely small airways. Wheezing can also occur when an infant inhales a foreign object or a piece of food into the lungs. Cystic fibrosis also causes wheezing, according to KidsHealth, although other symptoms, like delayed growth, are also present.
