Common causes of puffy eyes in a baby include viral or bacterial infections such as conjunctivitis, and allergies. In addition, when puffy eyes in a baby occur immediately after delivery, it may be related to pressure being exerted on the infant's face during the delivery process. This is very common when babies are delivered vaginally, though less common in babies delivered by Cesarean section.

Conjunctivitis can occur anytime, and is very contagious. Older children who are infected can easily transmit conjunctivitis to a baby. In addition to direct contact, conjunctivitis can also be transmitted through washcloths, towels, or bedding. Puffy eyes in a baby can also occur as as result of environmental irritants such as household cleaners, laundry soaps, and perfumes.

Although puffy eyes in a baby are a common symptom of conjunctivitis or pink eye, this is seldom the only symptom. Other manifestations of this condition include red, irritated or bloodshot eyes, excessive tearing, watery discharge, and profound itching. In addition, eyelid crusting and light sensitivity are common. Treatment for bacterial conjunctivitis includes antibiotics, however, if the condition is related to a viral infection, antibiotics will not be effective.

The appearance of puffy eyes in a baby can look ominous, but it is usually not serious. In addition, many cases of puffy eyelids in babies are simply the result of crying. Also, after delivery, a baby's eyes are instilled with eye drops to help prevent eye infection. The puffiness may be the result of these drops and will resolve in a day or two. These eye drops can burn, but are generally harmless to a baby's sensitive eyes.

Sometimes, puffy eyes in a baby can be caused by a blocked tear duct. This condition prevents tears from draining, and can even cause the eye to look as if it's swollen shut. Blocked eyelid glands can also cause puffy or swollen eyes in babies, as can a sty. A blocked tear duct usually clears up on its own, but if the problem persists, a minor procedure using a probe to alleviate the obstruction can be used.

Since babies are unable to make their needs known, parents and caregivers should be on the lookout for excessive eye rubbing that may indicate eye irritation. If symptoms persist, the baby should be seen by a pediatrician to determine the cause of the puffiness or irritation. The pediatrician may refer the baby to an eye doctor who can recommend further testing to determine the cause. In rare cases, the baby may be found to have a corneal abrasion, caused by scratching the cornea with a fingernail or other object.