Common Childhood Illnesses

Sometimes it seems like your child is always getting sick. Due to their underdeveloped immune systems, and the fact that they frequently put their hands or other things in their mouth, children are more susceptible to illnesses. This list is meant to highlight common infant and childhood illnesses but should not be considered a complete list. Based on your child’s symptoms, you should contact your child’s pediatrician for advice. Timely treatment of symptoms can prevent an illness from worsening or becoming an emergency. Many of these illnesses have vaccines that reduce the risk of infection.

Information has been pulled from the Centers for Disease Control and Prevention (CDC), Hartford Hospital, and the American Academy of Pediatrics via

Chickenpox (Varicella)

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV). It can cause an itchy, blister-like rash, among other symptoms. The rash first appears on the chest, back, and face then spreads over the entire body.

Common Cold

Colds are upper respiratory infections caused by viruses. In the first two years of life alone, most children have eight to ten colds. And if there are older school-age children in your house, you may see even more, since colds easily pass from one child to another.


COVID-19 is a disease caused by a type of coronavirus. This illness was first found in 2019 and has since spread worldwide (pandemic). Symptoms can range from mild, such as fever and body aches, to severe, including trouble breathing. 

Cronobacter Infection

Cronobacter sakazakii (or “Cronobacter”) is a bacteria that can live in dry foods, like powdered infant formula, powdered milk, herbal teas, and starches. It has also been found in contaminated feeding items like breast pump equipment. Cronobacter infections are often very serious for babies who are younger than 2 months or were born prematurely.


Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make toxin. It can lead to difficulty breathing, heart rhythm problems, and even death.

Ear Infections

Ear infections have many causes including bacteria, viruses, and fluid in the ear. The most common complaints include ear pain, hearing loss, and drainage.

Group B Strep

Group B streptococcus (GBS) is bacteria that can cause serious illness, particularly in newborns. It is responsible for many cases of meningitis, in infants, as well as some cases of blood infections (sepsis) and pneumonia. 

Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease is an illness that causes sores or blisters in or on the mouth and on the hands, feet, and sometimes the buttocks and legs. It is common in children under 5 years old, but anyone can get it. The illness is usually not serious, but it is very contagious. It spreads quickly at schools and child care centers. 


When children have hepatitis, it means that they have an “inflammation of the liver.” Hepatitis often is caused by a virus. 

Influenzae Type B (Hib) Disease

Bacterial infections caused by Hib are usually spread by sneezing and coughing and are responsible for childhood illnesses such as meningitis and epiglottitis. They can also cause some cases of pneumonia and ear infections. Despite the name of these bacteria, they are not responsible for influenza (flu).

Influenza (Flu)

Influenza (flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. Flu symptoms are usually worse than a cold and last longer.


Jaundice is the yellow color seen in the skin of many newborns. It happens when a chemical called bilirubin builds up in the baby’s blood.

Parasitic Diseases & Children – CDC

Pertussis (Whooping Cough)

Whooping Cough is caused by bacteria that attack the lining of the breathing passages. Because a child is short of breath, they inhale deeply and quickly between coughs. The breaths often make “whooping” sounds, which is how this illness got its common name.

Pink Eye (Conjunctivitis)

Pink Eye is the inflammation (ie, redness, swelling) of the thin tissue covering the white part of the eye and the inside of the eyelids.

Recreational Water Illness (RWI) – CDC


Rotaviruses are the most common cause of severe diarrhea in children younger than 2 years. Nearly all children will be infected with this virus by 3 years of age. Rotavirus commonly causes severe, watery diarrhea and vomiting in infants and young children which can result in dehydration.


Shigella germs spread when people put something in their mouths or swallow something that has come into contact with the stool of someone sick with Shigella. Children may get Shigella germs on their hands by touching surfaces (for example, toys, bathroom fixtures, changing tables, diaper pails) that a sick person used.

Sudden Infant Death Syndrome (SIDS)

SIDS is the unexplained death of a seemingly healthy baby less than a year old. Most of these deaths occur while babies are sleeping, which is why we also call these deaths “sleep-related deaths.”

Sinus Infections

Sinus infections happen when fluid builds up in the air-filled pockets in the face (sinuses). This fluid buildup allows germs to grow. Viruses cause most sinus infections, but bacteria can cause some sinus infections.

Sore Throat

A sore throat can be a symptom of strep throat, the common cold, allergies, or other upper respiratory tract illnesses. Sore throat caused by a virus or the bacteria called group A Streptococcus can have similar symptoms.