Flu in Children: How to Recognize the Symptoms and When to See a Doctor

Influenza (the flu) is an acute viral infection that affects the respiratory tract and can cause complications. The disease is most common during the autumn and winter months. Young children, particularly those under 5 years of age, as well as children with chronic conditions, are especially vulnerable.

Unlike many other acute respiratory viral infections (ARVIs), the flu often starts suddenly and is accompanied by a significant deterioration in a child's general condition. Just a few hours earlier, the child may have felt well, but then develops a fever, weakness, headache, and other symptoms.

At Dobrobut Medical Network, we follow the principles of evidence-based medicine: we help identify the cause of the illness quickly and prescribe only medications with proven effectiveness that are safe for children. If you are concerned about the first signs of flu in your child, our pediatricians and doctors are available around the clock to provide professional medical care.

How Does the Flu Spread and What Is Its Incubation Period?

Influenza is caused by the influenza virus. It spreads mainly through inhaling infectious respiratory particles released when an infected person breathes, talks, coughs, or sneezes. Infection can also occur through contaminated hands and surfaces, although this route is considered less common.

After entering the body, the virus multiplies in the cells of the respiratory tract. The incubation period — the time between infection and the appearance of the first symptoms — is usually about two days, but can range from one to four days. If you notice that your child's condition is deteriorating rapidly, the characteristic symptoms of flu in children can help distinguish it from a common cold within the first few hours.

Main Symptoms of Flu in Children

The most common symptoms of flu in children include:

• a sudden rise in body temperature;
• chills;
• pronounced weakness and fatigue;
• headache;
• muscle and joint pain;
• dry cough;
• sore or irritated throat;
• runny or blocked nose;
• loss of appetite.

Some children, particularly younger ones, may also experience nausea, vomiting, and diarrhea.

The severity of symptoms can vary depending on the child's age, overall health, and the course of the illness. The absence of a high fever does not rule out influenza.

When Should You See a Doctor?

Contact a pediatrician if your child's condition causes concern, the fever persists, symptoms become more severe, or the child's condition worsens again after a temporary improvement.

It is especially important to seek medical advice promptly if your child has asthma, diabetes, heart or lung disease, an immunodeficiency, or another condition that increases the risk of complications. Children in high-risk groups may need medical assessment at the very beginning of the illness.

Seek immediate medical attention if your child has any of the following symptoms:

• difficulty breathing or unusually rapid breathing;
• the chest pulling inward when breathing in;
• bluish lips or face;
• severe chest pain;
• marked lethargy, confusion, or difficulty waking the child;
• seizures;
• signs of significant dehydration, including no urination for an extended period;
• a sudden deterioration after a temporary improvement.

How Is Flu Diagnosed in Children?

A doctor makes the diagnosis based on the child's symptoms, medical history, physical examination, and assessment of their condition. In many cases, no additional tests are necessary.

When indicated, the doctor may recommend testing for the influenza virus. This may include rapid influenza antigen tests or molecular diagnostic methods, such as polymerase chain reaction (PCR). The choice of test depends on the clinical situation and the availability of testing.

If a complication such as pneumonia is suspected, the doctor determines whether further investigations are needed. Depending on the child's condition, these may include laboratory tests or imaging studies.

Usually, no special preparation is required for a routine pediatric examination. If testing is planned, follow the healthcare professional's instructions. A timely visit to the clinic helps clarify the symptoms of flu in children and develop a safe care plan without delay.

What to Expect During Recovery

The main symptoms of uncomplicated influenza usually begin to subside gradually over several days, and most symptoms resolve within about a week. However, a cough, weakness, and fatigue may persist for longer.

During recovery, it is important to ensure that your child has:

• enough rest and a full night's sleep;
• regular fluids in small amounts;
• a comfortable indoor environment and regular ventilation;
• a gradual return to their usual activity level as their condition improves.

If symptoms do not improve, become more severe, or a fever returns after the child has started feeling better, seek medical advice again.

Flu Prevention

To reduce the risk of infection, it is recommended to:

• wash hands regularly with soap and water;
• ventilate indoor spaces;
• avoid close contact with people who have symptoms of a respiratory infection;
• teach children to cover their mouth and nose with a tissue or the crook of their elbow when coughing or sneezing;
• avoid touching their eyes, nose, and mouth with unwashed hands;
• maintain a regular sleep schedule and provide a balanced diet.

Comprehensive flu prevention in children includes both following personal hygiene practices and creating a healthy environment at home.

Vaccination remains the most effective way to protect against influenza and its severe complications. Annual flu vaccination significantly reduces the risk of hospitalization and pneumonia in children.

If your child does develop the flu, the doctor may consider prescribing direct-acting antiviral medication, such as oseltamivir. These medications are most effective when treatment begins early — within the first 48–72 hours after symptoms appear. They are particularly recommended for children with severe influenza, hospitalized patients, and children in high-risk groups.

What Not to Do

To protect your child's health and avoid complications during the illness, never:

• Give acetylsalicylic acid (aspirin) without medical advice. Taking this medication during viral infections can cause a life-threatening condition known as Reye's syndrome, which involves severe damage to the liver and brain.
• Give antibiotics without a doctor's recommendation. Antibiotics act only against bacteria and are completely ineffective against influenza viruses. Unnecessary antibiotic use can disrupt the normal microbiota and contribute to bacterial antibiotic resistance.
• Rub your child with alcohol or vinegar. Cooling the body with alcohol- or vinegar-based solutions can cause toxic substances to be absorbed through the skin and trigger a dangerous spasm of blood vessels.
• Use heat treatments or steam inhalations when your child has a high fever. Mustard plasters, hot foot baths, and hot steam place additional strain on the cardiovascular system and may cause burns to the respiratory tract.
• Use immunomodulators or cough syrups without a doctor's prescription. Medications with unproven effectiveness and syrups that thin mucus are not recommended for young children because they cannot cough up the increased amount of mucus effectively.

To book a pediatric appointment, get a rapid diagnostic test, or arrange a vaccination, call our contact center or fill out the form on our website.