Flu: symptoms in adults and children, first signs

In November 1799, the Russian word "gripp" first appears in A. Kh. Vostokov's diary "My Chronicle" — a common name for the disease called influenza in Europe. Today more than 2000 variants of the virus have been described, but the patient's questions remain the same: how to distinguish flu from a cold, what will happen tomorrow, and when to call a doctor.

What is flu and how does it differ from a cold

Flu is an acute respiratory viral disease: influenza viruses primarily affect the upper respiratory tract, as well as the bronchi and, less commonly, the lungs. Among acute respiratory viral infections, it stands out for its potential severe course. However, over 200 types of respiratory viruses — adenoviruses, rhinoviruses, respiratory syncytial and others — produce a similar picture, so in everyday life any ARD is called "flu," which is mistaken; "stomach flu" is not flu at all, but gastroenteritis.

A cold develops gradually, over one or two days, and mainly affects the nose and throat; flu manifests within a few hours and is felt throughout the body. Fever with a cold is rare, with flu it is usual; aches, weakness, and headache are typical of flu, while with a cold a person is still able to go about normal activities.

First symptoms of flu

Symptoms appear on the 1st–4th day after infection, but the illness begins rapidly. The first signs:

• sudden high fever;
• muscle and joint pain, aches throughout the body;
• pronounced fatigue, exhaustion;
• dry cough, sore throat, runny nose;
• headache, difficulty sleeping, loss of appetite.

In children the picture is the same, but ear pain, eye pain, enlarged lymph nodes, and noticeably reduced activity are added. Vomiting and diarrhea occur more often in children than in adults. Cough is the most persistent sign: it lasts two weeks or longer.

Flu symptoms by day

From infection to the first complaints, one to four days pass. Then the illness strikes: within a few hours fever, aches, and cough develop, and the person can no longer continue normal activities. The most contagious period is the 3rd–4th day of illness, and in the first five days after infection the virus is transmitted especially easily.

By the end of the first week, most people's symptoms subside: the illness usually resolves within a week without medical help. If there is no improvement by the seventh day, this is a reason to see a doctor. Cough often outlasts the other signs, and recovery takes 7–15 days.

Influenza A in adults and children: features of manifestations

Influenza A viruses are the most common cause of seasonal flu, and only they are known as the cause of pandemics. The virus is variable. Flu symptoms are similar to other ARVIs, and the disease can be diagnosed with laboratory tests.

In people aged 65 and older, mortality among the sick reaches 1%, and this group accounts for up to 89% of all flu-related deaths. In children, ear pain, eye pain, enlarged glands, lethargy, and gastrointestinal manifestations come to the fore.

Can flu occur without fever

In typical descriptions, high fever opens the list, but the wording of complaints is broader: fever or a feeling of heat and chills. For similar but unconfirmed cases, there is a clinical diagnosis of "influenza-like illness."

Descriptions of flu are based on complaints: fever or a feeling of heat and chills, cough, sore throat, aches; the diagnosis is confirmed by a doctor using a laboratory test. Diagnosis begins with questioning, then a swab is taken from the nasal cavity or the posterior pharyngeal wall: rapid tests give results in 15–20 minutes but are less accurate than longer ones, which are performed in an hour or several hours.

When to see a doctor

Urgent consultation is needed if a child is ill and their condition worries the parents; if the person is 65 or older; if they are pregnant or have recently given birth; if there is a long-term disease — diabetes, heart, lung, liver, kidney, brain, or nerve diseases; if immunity is weakened, for example due to chemotherapy or HIV. The same reason is very poor health, shortness of breath, and no improvement after seven days of illness.

Flu itself is not a reason to call an ambulance; 103/112 — if sudden chest pain, severe shortness of breath (the person is gasping, gulping air, or cannot utter a word), or coughing up blood appears.

The material is for reference: it describes the signs of the disease and does not replace consultation with a doctor who sees a specific person.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer