The first indication of the common cold in a baby is often:

• A congested or runny nose
• Nasal discharge that may be clear at first but might thicken and turn yellow or green

Other signs and symptoms of a common cold in a baby may include:

• Fever
• Sneezing
• Coughing
• Decreased appetite
• Irritability
• Difficulty sleeping
• Trouble nursing or taking a bottle due to nasal congestion

The common cold is an infection of the nose and throat (upper respiratory tract infection) that can be caused by one of more than 100 viruses. Rhinoviruses are the most common.

Once infected by a virus, your baby generally becomes immune to that virus. But because so many viruses cause colds, your baby may have several colds a year and many throughout his or her lifetime. Also, some viruses don't produce lasting immunity.

A common cold virus enters your baby's mouth, nose or eyes. Your baby can be infected with a virus by:

• Air. When someone who is sick coughs, sneezes or talks, he or she might directly spread the virus to your baby.
• Direct contact. Someone with a cold who touches your baby's hand can spread the cold virus to your baby, who can become infected after touching his or her eyes, nose or mouth.
• Contaminated surfaces. Some viruses live on surfaces for two hours or longer. Your baby may catch a virus by touching a contaminated surface, such as a toy.

A few factors put infants at higher risk of a common cold.

• Immature immune systems. Infants are, by nature, at risk of common colds because they haven't yet been exposed to or developed resistance to most of the viruses that cause them.
• Exposure to other children. Infants spend time with other children, who don't always wash their hands or cover their coughs and sneezes, which increases your baby's risk of catching a cold.
• Time of year. Both children and adults are more susceptible to colds from fall to late spring.

• Acute ear infection (otitis media). This is the most common complication of the common cold. Ear infections occur when bacteria or viruses enter the space behind the eardrum.
• Wheezing. A cold can trigger wheezing, even if your child doesn't have asthma. If your child does have asthma, a cold can make it worse.
• Sinusitis. A common cold that doesn't resolve may lead to a secondary infection within the sinuses (sinusitis).
• Other secondary infections. These include pneumonia, bronchiolitis and croup. Such infections require evaluation by a doctor.