All you need to know about childhood illnesses: symptoms, treatments and advice

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There are many childhood illnesses. And many of them are highly contagious. This article looks at the most common childhood illnesses and how to treat them.


What is a childhood illness?

A childhood illness is a condition that occurs mainly in young children. Most are common, banal ailments. They can have two origins: viral or bacterial. 

For some diseases, there are vaccines and simple hygiene measures you can apply to avoid contracting them and stay healthy.

What are the most common childhood illnesses in infants?

Here are the most common childhood illnesses. All have different symptoms and treatments


Chickenpox is caused by the varicella-zoster virus (VZV). It's a highly contagious virus, most often found in late winter and spring l.

Varicella is transmitted in several ways: 

  • It can be transmitted by direct contact with skin blisters and mucous membranes;
  • Or directly through the respiratory tract and saliva.

A person infected with chickenpox is contagious between 24 and 48 hours before the rash appears, and continues to lbe contagious for about 1 week afterwards, until the vesicles become dry.

Symptoms of chickenpox include fever, and a rash that develops into vesicles (about 3 to 4 mm in diameter). The vesicles are also filled with a clear, dewy liquid. Itching may also occur.

Lhe intensity of the rash depends on the individual, with some people having very few vesicles, while others may have several successive outbreaks covering the whole body.

Chickenpox generally heals in 10 to 12 days

Most children who contract chickenpox as infants are immune.

Scarlet fever

Scarlet fever is a bacterial childhood illness. Caused by the streptococcus family, it produces symptoms such as fever, chills and angina (swollen neck glands and a red, swollen throat). Headaches, nausea, vomiting and stomach aches can also occur. 

One of the characteristic symptoms of scarlet fever is the appearance of a rash on the skin around two or three days after the onset of the sore throat.

Red spots make the skin feel rough and grainy. 


Bronchiolitis is a contagious viral disease , often impressive in its symptoms, but benign.

This disease affects children under the age of 2. Symptoms include respiratory discomfort, coughing and rapid, wheezing breathing. It lasts an average of 10 days. 

During the first ten days, infants are closely monitored. However, it is possible for some infants to develop a more severe form of bronchiolitis, requiring hospitalization

The virus is present in saliva and bronchial secretions, so it can be transmitted by sneezing, spitting, coughing, kissing , etc., as well as lthrough objects contaminated with saliva, such as children's toys.


Gastroenteritis can originate from a variety of sources: viruses, bacteria, parasites or fungi. But in children, most gastroenteritis is caused by a virus called "rotavirus".

Gastroenteritis manifests itself as :

  • diarrhea;
  • Nausea and vomiting;
  • loss of appetite;
  • stomach cramps;
  • fever;
  • fatigue.

Gastroenteritis generally doesn't last very long, with vomiting sfading away in about two days, while diarrhea can persist for one to two weeks. Gastroenteritis can lead to dehydration. 

Gastroenteritis is an infectious disease transmitted by : 

  • contact with a sick person;
  • eating contaminated food or drinkingcontaminated water;
  • contact with certain objects containing fine particles of stool and vomit from infected people.

Warning: a child may still be contagious in the days following the disappearance of symptoms.


Measles is lone of the most contagious diseases among linfants.

Symptoms include high fever, runny nose, diarrhea, conjunctivitis, loss of appetite and the appearance of patches on the body. 

It is contagious 6 days before the first signs appear, making it highly contagious. As measles sattacks the mucous membranes of the respiratory tract, it can lead to severe complications, including death. For this reason, it is compulsory to vaccinate babies against measles as soon as they reach 1 year of age. A booster shot is then required between the 16th and 18th month following the first vaccination.

The disease is transmitted via the mucous membranes of the respiratory tract.

Many other conditions

There are many other childhood illnesses, such as otitis , which is an ear infection caused by a virus or bacteria.

Mumps is a viral disease characterized by inflammation of the salivary glands. In some children, it causes no visible symptoms. 

Finally, hand-foot-and-mouth disease is a viral but benign illness. 

What about nocturnal enuresis and diaper rash?

L'ucturnal enuresis or "bedwetting ", is a common childhood problem. While they're asleep, they can't hold it in, so they urinate without realizing it. This can happen frequently or occasionally. Although bedwetting can be a cause for concern for parents, it is not a childhood illness, but rather a developmental disorder.

As fordiaper rashis an irritation of the skin around the diaper area. The result is redness and local inflammation of the skin. Likewise, it's not a childhood illness, but more a care problem or a skin reaction to the diaper's components. Good hygiene and protective creams can effectively prevent diaper rash.

What types of illnesses affect babies and lchildren?

There are many causes of childhood illness.

Viral or bacterial diseases

They can be viral in origin and give rise to fever, as in the case of bronchiolitis, bronchitis, gastroenteritis, acute laryngitis, hand-foot-and-mouth disease, chickenpox, roseola, mumps etc... 

Or of bacterial origin, as in the case of scarlet fever, certain gastroenteritis, whooping cough and bacterial meningitis.

Many can be prevented by vaccination.

Worms and parasites

Some can also be caused by parasites or worms. Examples include pinworms, giardiasis and ascariasis. 

Skin diseases

There are also dermatological diseases such as scabies, warts, atopic eczema, urticaria etc... 

Growth and environmental diseases

Some pathologies are caused simply by your baby's growth, such as scoliosis. Your child may also be prone to allergies (food or otherwise) and infant asthma. We can also mention 

When should a baby see a doctor?

If your child displays symptoms similar to those described in this article, it's advisable to consult your paediatrician. If you have any doubts about your baby's health, don't hesitate to seek advice.

FAQs on childhood illnesses

What are the main contagious childhood diseases?

The main contagious childhood illnesses are chickenpox, bronchiolitis, gastroenteritis and measles.

How to recognize childhood illnesses?

Children's illnesses have their own specific symptoms, which vary from one condition to another. The best way to recognize them is to visit a doctor or pediatrician.


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