According to the Centers for Disease Control and Prevention (CDC), millions of U.S. residents get the flu each year. While most recover without treatment, more than 200,000 have to be admitted to the hospital and about 36,000 die from flu-related causes. Flu can be especially serious for children younger than 2, the CDC says. Infant flu symptoms may be slightly different from symptoms in older children.
Systemic Symptoms
Systemic symptoms of the flu reflect the response of the immune system to the infection. They include fever, chills and sweats, headache, muscle aches and fatigue. According to the American Academy of Family Physicians, flu usually produces fever above 102 degrees Fahrenheit; however, the absence of fever does not necessarily rule out flu, the CDC notes. The immune systems of younger children may be less well-developed than those of older children, leaving them less able to mount a fever. Infants also can't tell you about their symptoms, so caregivers must rely on other cues such as irritability, lethargy, lack of appetite and increased need for sleep.
Respiratory Symptoms
Respiratory symptoms of the flu include cough, sore throat, runny nose and nasal congestion. According to the American Academy of Pediatrics, the cough associated with flu is usually dry, meaning it does not produce sputum. Most of the respiratory symptoms of flu in infants are easy to spot. The exception is sore throat. It may be difficult to get a good look at an infant's throat, but you can rely on other signs, such as food refusal and fussiness during feedings.
Gastrointestinal Symptoms
According to the CDC, flu in children sometimes is associated with vomiting and diarrhea. In infants, it may be difficult to differentiate vomiting from spit-up, which usually resembles breast milk or formula and occurs shortly after feedings. Vomiting may be brown or green (bilious), may occur unrelated to feedings and may happen more frequently than spitting-up. Similarly, infant stools normally are different from adult stools, which can make diarrhea difficult to diagnose. Stools that occur more frequently than normal or look different from the infant's usual stools may be diarrhea. Dehydration develops quickly in infants, so it's important to monitor urine output. Dark urine and fewer wet diapers may signal a problem.
