What are common childhood illnesses?

Experienced parents know that children often become sick from various conditions such as coughs and colds, sore throat and ears, rashes and stomach aches. Children tend to explore their world through touching and tasting and are more likely to touch their nose, mouth or eyes with a finger that has been contaminated by a potential infection.

As their immune system is still developing, children do not have enough immunity to fight of infections, which causes them to become sick more often than adults. This constant exposure to new illnesses is necessary to help build up a child's immune system, which enables them to fight off infections as they grow older.

The more common illnesses that children develop tend to be easily managed and treated, while maintaining good hand hygiene can also limit their spread. Furthermore, adhering to your local vaccination schedule will reduce the likelihood of a child contracting some of these illnesses, or will, at least, reduce the severity of the disease if it is contracted.

Fever in a child; feverish child.Children have an underdeveloped immune system. 

Immune system

The organs and cells involved in protecting the body against infection.




The body's ability to protect against an infection or toxin, generated by immunisations or exposure to previous infection.

Signs and symptoms


Chickenpox is a condition that is caused by primary infection with the varicella-zoster virus. Chickenpox is most common in children under 10 years of age, but anybody can potentially develop it if they have not been vaccinated or infected in the past. The introduction of a vaccine against the virus that causes chickenpox has seen a decline in the occurrence of chickenpox.

Chickenpox classically starts with a rash on the face, chest and back. The rash is associated with itchiness and, after a few days, the rash turns into blisters that become cloudy and form scabs. Other typical symptoms of chickenpox may include fever, headache, loss of appetite, a dry cough and nausea.

Chickenpox can be spread between people by directly touching the blisters, saliva or mucus of an infected person, by inhaling droplets from an infected person's coughing and sneezing and by touching contaminated items from an infected person.

A person with chickenpox is contagious for a few days leading up to the development of the rash and remains contagious until all their blisters have crusted over, which takes about six days.


Conjunctivitis, also known as pink eye, occurs when the outer layer of the eye and the inside of the eyelids become inflamed. Some of the more common symptoms associated with conjunctivitis may include redness and irritation to the eyes, itchy and teary eyes and pus around the eyes.

Conjunctivitis can last from a couple of days to a few weeks and can be caused by either a bacterial or viral infection, or an allergic reaction. Infective conjunctivitis is caused by bacteria or viruses and is easily spread between people by coming into contact with the fluid from the eyes of an infected person. Allergic conjunctivitis occurs when a substance, such as dust or pollen, comes into contact with the eyes and prompts an overreaction of the immune system.

Head lice

Head lice are blood-sucking insects that are spread through contact between people. Head lice are most commonly found on the scalp, but can also infest the eyelashes and eyebrows. Head lice cannot jump or fly and are not passed on through pets.

Head lice are very common in school-aged children and are most often spread by direct person-to-person contact. Head lice are less likely to be spread by hairbrushes, hats or pillowcases. They cause itchy skin on the scalp, neck or around the ears. The itching is caused by the saliva of the lice as they feed off the skin. Head lice lay their eggs on the hairs of the head.

Middle ear infections

A middle ear infection is an infection of the ear, behind the eardrum. Middle ear infections are caused by bacteria or viruses and often happen when a cold has set in. They usually resolve on their own without medical intervention. 

Middle ear infections are very common and may be associated with pain and fever. This type of ear infection is most common in children under six years of age. Children of this age are more likely to experience these infections because their Eustachian tubes are shorter and their positioning makes it easier for bacteria and viruses to find their way to the middle ear and once an infection sets in, the size of the tubes makes them more prone to blockage.

Persistent infections can cause hearing problems, impaired hearing and speech, or developmental delays.


Nappy rash

Nappy rash is very common in babies between the ages of nine weeks and 12 months. Nappy rash presents as red and inflamed skin around the genitals, bottom and thighs. Nappy rash can be caused by leaving a soiled nappy on for long periods, chemical exposure (e.g. from baby wipes or lotions) and can be aggravated by a yeast infection (thrush).

Fifth disease

Fifth disease is also known as slapped cheek syndrome, or its official name, erythema infectiosum. Fifth disease is caused by a parvovirus, and is usually a mild condition that resolves on its own without medical intervention. Fifth disease is commonly passed on by fluid droplets from sneezing and coughing.

The symptoms generally appear about 4-14 days after the infection has occurred, however, many children also do not develop any symptoms from the infection. In the early stages it can be associated with cold-like symptoms such as mild fever, headache and a sore throat, which gradually fade and the characteristic red rash appears on the cheeks. By the time the rash has appeared, children are no longer contagious.

Roseola infantum

Roseola infantum is a mild infection that is also known as sixth disease or exanthema subitum. It typically affects children aged six months to three years. It is caused through an infection by a species of the herpes virus that does not cause cold sores. Roseola infantum is contagious and is spread by fluid droplets through coughing or sneezing and is associated with a raised red skin rash and fever that may last from a few hours to days. As the fever subsides, a raised red rash appears, first on the body and neck and later on the face, arms and legs. This condition generally resolves within a week and does not usually require medical intervention.

Hand, foot and mouth disease

Hand, foot and mouth disease is a mild illness that most commonly affects children under five years of age and is more prevalent during warmer months. It is commonly associated with blisters on the fingers, palms, soles of the feet, mouth and sides of the tongue, but some children also experience a sore throat, fever and lack of appetite.

Hand, foot and mouth disease is caused through an infection by Coxsackie virus and spread by droplets from sneezing and coughing, through faecal matter or from the fluid of the blisters of an infected person. The virus can still be spread through faecal matter up to a number of weeks after the symptoms have cleared up.


Asthma is a common condition that affects the lungs and impairs breathing. Asthma is characterised by whistling or wheezing sounds when breathing, tightness in the chest, frequent coughing spells, rapid breathing, laboured breathing and shortness of breath.

During an asthma attack, the airways of the lungs become inflamed, swollen and filled with mucus. The muscles around the lungs tighten, which causes the airways to narrow and makes it increasingly difficult to breathe.

Asthma can have various triggers and some of the more common triggers may include lung infections, strong emotions and stress, cold air, exercise, sudden changes in weather or temperature, and airborne allergens. Asthma is often linked to other allergic conditions such as eczema and hay fever and it tends to run in families.


Croup is a condition that is characterised by a barking cough, a hoarse voice and noisy breathing. Croup, also known as laryngotracheobronchitis, is usually caused by a viral infection that leads to inflammation of the upper airways, which are comprised of trachea and bronchi. It develops over several days and often occurs after more typical cold or flu symptoms such as sore throat, mild fever and runny nose.

Croup most commonly affects children under five years of age, as their small and soft windpipes are more vulnerable to swelling and inflammation. Most cases of croup are mild and resolve within 3-7 days without medical intervention.


Tinea is a highly contagious fungal infection that can affect the scalp, face, body, feet or nails. A tinea rash has a characteristic circular pattern that develops on the skin once infected. This usually appears within 10-14 days after infection.

Tinea can cause the skin to become dry, scaly, yellowish and crusty. Tinea is spread by direct contact with an infected person or pet, or it can be picked up from damp floors and showers, especially in communal areas such as gyms and swimming pools.


Gastroenteritis is caused by inflammation of the lining of the small and large intestines and stomach. Symptoms, which may include fever, vomiting, abdominal cramps and diarrhoea, usually appear 12-48 hours after infection and may last up to three days. Gastroenteritis can be caused by infection with bacteria, viruses or parasites.

An infection may be passed on by eating and drinking contaminated food and water, or through the faecal-oral route from another person carrying the infection. Due to its highly contagious nature, gastroenteritis can spread quickly through schools and communities.

For most mild cases, gastroenteritis is generally a short-term condition, but more severe symptoms may prompt medical intervention.

Cold and flu

Cold and flu are both contagious respiratory illnesses, but colds are generally associated with milder symptoms, while the flu, or influenza, is usually accompanied by fever, aches and chills. Children may also experience a fever when they have a cold, as their bodies are not properly equipped to fight off an infection without raising their body temperature. Young children may experience colds regularly because they have not had the chance to build up immunity to the various viruses that can cause colds.

Colds tend to only last a few days and are often associated with sneezing, a runny nose, coughing, a dry throat and mild body aches and headaches. Flu can last for over a week and has similar symptoms to a cold, but tends to cause more severe and intense fever, body aches and extreme tiredness.

Colds and flu tend to be more common during winter months because the cold weather means people tend to stay in closer contact indoors, making it easier to spread infection.

Sore throat

Children often experience sore throats. Most sore throats in young children are caused by viral infections that resolve without medical intervention. Sore throats of viral origin may also be accompanied by a fever.

School-aged children tend to develop sore throats after infection with group A Streptococcus bacteria. Group A sore throats are also called strep throat and may be accompanied by other symptoms such as swollen glands in the neck, white patches of pus in the back or sides of the throat or small red spots on the roof of the mouth. If younger children are infected with group A Streptococcus, they may have a thick nasal discharge, fever and a lack of appetite. 

Food allergies

Up to one in five children have at least one food allergy. Children who have a food allergy also commonly have other allergic conditions such as asthma or eczema. Common food allergies include cow's milk, peanuts, fish, shellfish, tree nuts, eggs, soy and wheat. The most severe allergies tend to be associated with peanuts, tree nuts, fish and shellfish and tend to last a lifetime, while children may outgrow allergies to food such as wheat, eggs, soy and cow's milk.

Food allergies can cause symptoms such as hives, rash, swollen lips and tongue, nausea, vomiting, diarrhoea, wheezing and a drop in blood pressure. Severe allergic responses require immediate medical attention and children with known allergies may be prescribed an auto injector of adrenaline in case of anaphylaxis.

Anxiety and depression

Until children are around eight years of age, they do not experience anticipatory anxiety; for example, they are not overly preoccupied about an upcoming event or situation. As children grow older, they start to develop the capacity to think ahead and may worry or become stressed, thinking about getting sick or hurt, or about losing family members. Children who experience excessive levels of anxiety may perform more poorly at school, they may miss out on social experiences or they may go on to develop relationship problems and depression.

Depression is more common in teenagers and is associated with changes in behaviour such as becoming more withdrawn or isolated, a marked drop in school performance, changes in sleeping and eating patterns, angry outbursts and a prolonged sad mood. Depression is a very complex condition and treatment can vary widely.

Allergic reaction

A problematic physiological response to an allergen that comes into contact with the body.


Airway passages that branch from the windpipe, which themselves branch into smaller passages. Bronchi is plural of bronchus.

Eustachian tubes

A tube that links the back of the nose to the middle ear.

Immune system

The organs and cells involved in protecting the body against infection.


A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.


A bodily fluid that is the result of an inflammatory response at an infection site. Its colour can range from whitish to yellow to green, depending on the composition. Pus is mainly composed of dead bacteria, white blood cells and cellular debris.


Also called the windpipe. A cartilaginous tube in the neck that connects the throat with the airways of the lungs.


A single-celled fungus that can causes infections. Candida, the cause of thrush, is an example of a yeast.



Risk factors

The risk factors for common childhood illnesses vary, depending on the specific illness and its associated cause. Some contagious conditions are more likely to occur during cooler months, when children are indoors and infection is more easily spread. Not keeping up to date with the recommended childhood immunisations can put your child at risk for some illnesses.

Methods for diagnosis

Many of the conditions described here can be diagnosed by a doctor conducting a physical examination, taking a medical history and assessing the presenting symptoms. Some conditions require further diagnostic testing, such as asthma, the diagnosis of which involves measuring lung function and capacity, or food allergies, for which diagnosis may involve skin prick testing. 

Types of treatment

The underlying cause of an illness and the severity of symptoms will determine the appropriate treatment for an illness. Many illnesses listed here are generally mild and are likely to resolve on their own and may be well managed with home care.

Potential complications

Most of the common childhood illnesses resolve with simple home care and do not require medical intervention. 

Some of the more serious symptoms that may be associated with common childhood illnesses may include:

  • A high fever that lasts more than 48 hours;
  • Blood in urine or vomit;
  • Rashes that appear suddenly and spread quickly;
  • Excessive sleepiness or confusion;
  • Severe breathing difficulties and wheezing, and;
  • Severe diarrhoea and/or vomiting that lasts for more than 24 hours.

Serious symptoms like these require prompt medical attention.


Because children often play and study in groups, they are more likely to spread some of the contagious illnesses described here. Some contagious infections are spread by direct and indirect contact by droplets from sneezing and coughing, while others can remain on surfaces, such as toys or handles, for hours.

Infections that affect the gastrointestinal tract are spread by eating and drinking contaminated food and drinking water, or by coming into contact with the faecal matter from someone carrying an infection, such as through changing nappies.

By teaching your children to wash their hands regularly, especially after going to the bathroom, before eating and drinking, after blowing their nose and after touching a pet, you can help lessen the chance of them contracting a contagious infection. By recognising an infection early on, you can reduce its spread by practising good hand hygiene within your family and keeping the home clean and tidy by disposing of used tissues and wiping down countertops and surfaces as much as possible, which will reduce the chance of other family members falling ill.


Child and father washing hands; preventing spread of infection using hygiene; good hand hygiene.Proper handwashing reduces the spread of contagious infections. 

