Doctors define wheezing as a high-pitched or whistling sound that occurs when exhaling. Uncommon during the first two months of life, wheezing is most likely to occur between 2 and 5 months of age, according to Children's Memorial Hospital of Chicago. Several conditions can cause infant wheezing, and all require parents to seek medical attention.
Respiratory Infections
Viral respiratory infections, in particular respiratory syncytial virus or RSV, can cause an infant's first wheezing attack. These infections usually occur during the cold winter months, and cause fever along with coughing and wheezing. Between viral attacks, wheezing ceases and the child appears otherwise healthy.
Foreign Object Inhalation
Coins, small toys, or anything small enough for busy infants to put in their mouths or noses while exploring, can accidentally block their lower airway. According to MedlinePlus, when an infant inhales a foreign object into the respiratory tract, it can cause breathing problems and lead to infection. Depending on the size of the inhaled object, wheezing is often the only symptom.
Asthma
While wheezing is a common sign of asthma, not all infants who wheeze will go on to develop asthma. In addition to wheezing, an infant with asthma will usually breathe louder or faster than normal, and have frequent coughing fits that get worse after actively playing. Infants with asthma often experience clear runny noses due to allergies. Doctors usually do not diagnose asthma until an infant is older, according to MayoClinic.com.
