Pneumonia, a lung infection, is caused by several microorganisms, including bacteria, viruses, parasites and fungi, states KidsHealth, a medical resource provided by the Nemours Foundation 2. Depending on the cause, infants with pneumonia may require medical treatment to assist with breathing or fluid replacement 2. Like any infection, treatment of pneumonia is based on the cause 2. Symptoms of pneumonia in an infant tend to be similar regardless of the cause of the infection 2.

Respiratory Symptoms

Pneumonia primarily affects the lungs 2. An infant may only have symptoms of pneumonia that involve breathing, such as rapid breathing, labored breathing or noisy breathing 2. It is evident that an infant's breathing is labored when the skin is pulled tight across the ribs with each inhale. The nostrils may retract and flare with each breath as well. Wheezing or whistling sounds while inhaling or exhaling can also be symptoms of pneumonia 2. The University of Michigan Health System explains that chest rattling is possible in infants but it is not always a definite sign of pneumonia 2. Noisiness is because of fluid building up in the lungs, specifically in the air sacs (alveoli). This fluid is the primary cause of all respiratory signs of the infection.

Abdominal Symptoms

When a respiratory infection impacts the lower parts of the lungs, abdominal symptoms of illness can be the result, states KidsHealth 2. An infant may vomit or cry from abdominal pain. Other signs that an infant is suffering from stomach pain include pulling the knees upward, crying inconsolably or refusing to eat.

Other Symptoms

The American Academy of Family Physicians says some of the strongest predictors of pneumonia in children include a fever and cyanosis, a blue tint to the skin 12. An infant without a fever and respiratory symptoms isn't likely to have pneumonia, says the AAFP 2. An infant's temperature can get as high as 104 degrees Fahrenheit. Depending on the infant's pediatrician and age, any temperature over 100 degrees may require immediate medical attention. In extreme cases, an infant may have blue or gray lips and/or fingernails. This discoloration is the result of blood cells having inadequate oxygen supply, making them easy to see through the skin.