Sinuses are not fully developed until age 20. This makes diagnosing a sinus infection in a child or infant more difficult, the American Academy of Otolaryngology Head and Neck Surgery states. Signs of a sinus infections in an infant can be subtle. Distinguishing a sinus infection from the common cold or some other illness can be done by examining the signs of illness that exist. Sinus infection symptoms may not be the same for every infant.
Length of Illness
The common cold and a sinus infection share many symptoms. A sinus infection can resemble a common cold that gets worse over time. Instead of improving, the cold symptoms may be persistent. When cold-like symptoms persist beyond 10 to 14 days, it is possible the infant has a sinus infection.
Drainage
A sinus infection causes mucus to drain from the nose and down the back of the throat. The nasal discharge may be yellow or green. As the mucus drains, it can irritate the throat and make it sore or cause an infant to cough. Pain in the throat is just one of several reasons an infant may have poor feeding habits while ill. A sinus infection may also cause a reduced appetite or difficulty breathing through the nose while eating.
Fatigue
An infant may be more fussy than normal when ill or show a lack of interest in activities. This can interfere with playtime or make interacting with a baby more difficult. Sleeping may be interrupted by coughing, especially at night. Eye swelling may be worse in the morning from the infection of the sinuses. Darkened tissue around the eyes can be another sign of a sinus infection.
Other Symptoms
An infant may cry or fuss more when placed on her back to sleep. This could be due to an infection resulting from buildup of fluid in the ear. An ear infection isn't an actual sign of sinus infection but it does commonly accompany infection of the sinuses. A low fever--less than 100 degrees F--is possible, but is not common in infants.
