Influenza: symptoms, treatment, duration

Influenza: symptoms, treatment, duration

Influenza is a serious respiratory disease caused by viruses. Flu is very contagious. Especially in the winter months many people fall ill. However, a simple cold is often mistaken for flu, although the differences are very large. Read here which symptoms are typical for a flu and how you can protect yourself!

Brief overview

  • Symptoms: sudden onset of fever with chills, bone pain, chesty cough, sore throat, headache, sometimes gastrointestinal problems
  • Infection: via fine droplets in the air we breathe, contact with contaminated objects and surfaces
  • Pathogen: Influenza A and B viruses, which can change rapidly (therefore no permanent immune protection)
  • Prevention: Vaccination (for risk groups), avoid contact with infected persons, wash hands regularly
  • Treatment: only symptomatic with pain and fever medication (ibuprofen, paracetamol), bed rest, drink a lot
  • Possible complications: Pneumonia, sinusitis, middle ear inflammation, heart muscle inflammation, meningitis

Flu: Symptoms

Anyone who lies in bed with a cough, a cold and a fever often wonders whether he is suffering from a flu or a cold (flu-like infection). The most important distinguishing criterion is that while you slowly get worse when you have a cold, the flu suddenly hits you.

Flu or cold? The most important differences


Flu “Common cold” (flu-like infection)
sudden fever of at least 38.5°C slowly rising or no fever at all
Fever usually lasts longer than three days Fever often only temporary
severe feeling of illness mild to moderate feeling of illness
often nausea, vomiting, diarrhoea no gastrointestinal problems or mild nausea
thereafter often persistent performance weakness then quickly efficient again


The most common signs of influenza are high fever, chills and a pronounced feeling of illness. A dry dry chesty cough is also often experienced by those who are ill. Here you will find an overview of all possible flu symptoms:

  • high fever
  • Chills
  • Exhaustion
  • dry dry cough
  • rare cough with tough, partly bloody sputum
  • Sniffles
  • Sore throat
  • Pharyngitis
  • Conjunctivitis
  • Gastrointestinal complaints such as nausea, vomiting, diarrhoea
  • Headache
  • Sensitivity to bright light (photophobia)
  • bloated face
  • Joint and muscle pain


    The main objective here for a diagnosis, is to rule out other diseases as the cause of the symptoms and to identify patients at risk. So that the flu does not take a serious course. The best way to protect yourself from this is to have your annual flu vaccination. This generally reduces your risk of being infected.

    Influenza is transmitted by droplet infection e.g. by sneezing, coughing, kissing or shaking hands. This means that basic hygiene measures such as hand washing or hand disinfection are advisable. Also avoid contact with sick people. A mouthguard would also help – but this is difficult to implement. The basic rule is: a healthy lifestyle with a balanced diet and exercise strengthens the immune system and protects against illness.

    The cause of influenza is a virus. Therefore, a therapy with drugs is difficult. There are active substances, but they have to be taken very early on and do not shorten the duration of the disease. If you have influenza, lie down in bed and lower your fever if necessary, either by taking medication or by measures such as calf compresses.

    Flu: Special symptoms

Influenza viruses do not cause typical symptoms in every person. Although they can spread and multiply quickly, they often cause only minor symptoms. For example, flu headaches are interpreted as migraines, or exhaustion due to illness is interpreted as work-related exhaustion.

In children, influenza is often accompanied by inflammation of the middle ear with earache. Infants can develop a so-called pseudocroup: An inflammation of the larynx below the glottis causes a barking cough.

After a cured flu many people feel weak and tired for a long time, suffer from circulatory problems and headaches. Even if a person suffering from influenza has not taken sufficient care of himself or herself, the illness can last longer. Coughing and fatigue can then last for weeks. In this case one speaks of a “dragged flu”.

Flu: complications

For people with a weak immune system, there is a risk that the flu will take a complicated course. At risk are children, pregnant women, elderly people, people with chronic diseases such as asthma or people taking immunosuppressive drugs.

If the immune system is running at full speed due to the flu virus infection, the body is more susceptible to other diseases. Then bacteria can enter the body more easily. This is called a super infection. The first signs of this are a renewed rise in fever and weakness or a cough that gets worse again. The following complications can result from such a bacterial superinfection:

Inflammation of the respiratory tract

Paranasal sinusitis often develops as a bacterial superinfection in influenza. People who suffer from asthma or COPD often also suffer from pneumonia caused by bacteria during flu. It is even more common than pneumonia caused by the influenza viruses themselves. Bacterial pneumonia is a life-threatening complication and the most common cause of a fatal course of influenza.

Inflammation of the middle ear

Children in particular often get a bacterial middle ear infection in addition to the flu.

Heart inflammation

The heart can also be affected by influenza. If the heart muscle becomes inflamed, this is called myocarditis. In pericarditis, the pericardium is inflamed. Myocarditis is a dangerous complication because it often causes few symptoms. Occasionally fever, chest pain and noticeable cardiac arrhythmia occur. If people who unknowingly suffer from myocarditis exert themselves too much, the risk of sudden cardiac death is increased.

Pericarditis usually does not progress as dramatically and heals on its own after some time. In both cases, however, hospitalisation and bed rest are necessary to reduce the risk of further complications.


In rare cases, influenza can develop into meningitis. In addition to fever, severe head and neck pain and “stiff neck” may occur. If confusion, drowsiness or a seizure is added to these symptoms, it is most likely that not only the meninges but also the brain has become inflamed.

Influenza: protection against infection

When someone who has the flu sneezes or coughs, the viruses – enclosed in fine secretion droplets – fly through the air. If the droplets are inhaled by other people, they too can fall ill with flu. Even if one touches surfaces contaminated with influenza viruses, one can become infected, for example, by door handles, PC keyboards, bus stops on the bus, or if one shakes hands with a flu patient.

You can reduce your risk of infection by

  • wash your hands regularly
  • do not touch the face and especially the eyes with your hands (influenza viruses are often collected with your hands and could reach the mucous membranes)
  • waive the handshake
  • avoid large crowds
  • keep the room air moist (dry heating air removes moisture from the airways and makes it easier for pathogens to enter)

As with any infectious disease, people who come into contact with the pathogen more frequently are particularly at risk. Therefore, people working in medical facilities such as hospitals, medical practices, old people’s or nursing homes have an increased risk of infection. However, the flu viruses can also spread faster in schools, kindergartens and day-care centres.

Preventing influenza: vaccination

The best way to protect yourself from an influenza infection is to have a vaccination. People with a weak immune system are recommended to be vaccinated.

The best time for a flu vaccination is in autumn. However, because flu viruses change very quickly, the vaccination must be repeated every year to be effective. Recent studies show that repeating the vaccination every year can further improve protection against influenza.

You can read about what you need to know about the vaccination and more information about flu vaccination here: Flu Vaccination

Influenza: treatment

The flu can only be treated to a limited extent at its source. However, the symptoms can be considerably alleviated by various means.

Flu treatment: medication

There are special drugs against influenza viruses that block the protein neuraminidase. These so-called neuraminidase inhibitors prevent the influenza viruses from multiplying further. As a result, the disease usually progresses much milder and shorter. However, these only work in the first two days after the onset of symptoms. Neuraminidase inhibitors are also not effective against all influenza viruses and have some side effects.

Influenza viruses are coated by the enzyme neuraminidase, which enables them to detach from the infected cell after multiplication. The group of drugs known as neuraminidase inhibitors prevents the detachment, so that the newly formed viruses stick to the cell membrane and cannot spread further in the body.

If the flu takes a complicated course, bacteria often cause disease symptoms in addition to the influenza viruses. Such a bacterial superinfection can then be treated with antibiotics. These kill the bacteria, but do not work against the influenza viruses.

Alleviation of the symptoms

Various drugs can reduce the flu symptoms and thus make the disease more bearable. Painkillers such as ibuprofen, acetylsalicylic acid or paracetamol help against headaches or aching limbs. Caution: Children should not take acetylsalicylic acid during flu. High fever can be treated with antipyretic medication – the above-mentioned active ingredients also help here. In addition, cough syrups or decongestant nasal drops can be useful in the event of corresponding symptoms.

Flu treatment: home remedies

Household remedies are often used in conjunction with drug therapy.

You can read about which household remedies are suitable for influenza in the article Household remedies for colds and flu.

Influenza: Course of the disease and prognosis

One to four days after one has been infected with the influenza virus, the first symptoms appear. However, infected persons are often contagious themselves even before the outbreak of symptoms.

The flu can take a very different course. With a normal flu, the fever disappears after five to seven days. However, symptoms such as coughing, a cold or a feeling of weakness can last another week or two.

For people with a weakened immune system, such as children, the elderly, pregnant women or patients with chronic illnesses (especially respiratory diseases), a flu often lasts longer. Complications can then also occur, which in rare cases can even be fatal.

Because the influenza virus constantly develops new subtypes due to altered gene segments, people can fall ill with influenza several times in their lives. In contrast to other infectious diseases, which you only get once because the immune system has developed effective protective mechanisms against the pathogen, you do not become permanently immune to influenza.

This applies at least to the more common influenza A virus. However, there are different types of influenza virus. Type B changes much more slowly, so that one usually only falls ill with influenza once in one’s life from influenza B viruses, often already in childhood. The disease is usually mild.

How does a summer flu go?

The course of the so-called summer flu, which is actually not a “real flu”, is also usually mild. This is because it is not caused by influenza viruses, but by enteroviruses. As the name suggests, it usually occurs in summer and is similar to a cold.

How to distinguish summer flu from influenza and information on the treatment of summer flu can be found in the article Summer flu

Flu: examinations and diagnosis

Anyone who suspects they have been infected with the flu virus should see a doctor. In particular, people with an increased risk, such as the elderly or chronically ill, should consult their family doctor at the first sign of influenza.

In many cases, the doctor can already determine whether a patient is suffering from influenza or just a flu-like infection (cold) based on the patient’s medical history and a physical examination. However, if the patient is very ill or there is a risk that the disease will take a severe course, virus detection is useful. If the result is positive, treatment against viruses can be started immediately.

Influenza virus detection

The rapid influenza test provides an important indication as to whether these are actually flu viruses. For this test, saliva is swabbed from the nose or throat with a cotton swab and applied to a test strip. If the test is coloured, an influenza infection is very likely.

Sometimes, however, the material has to be sent to a laboratory where a genetic analysis can identify the virus one hundred percent.

Duty to notify

In a hospital, for example, sick people are isolated in a single room. Visitors and medical staff must wear protective clothing when entering the sickroom. Washing hands regularly also helps to prevent the virus from being passed on to other people.

Influenza: The influenza virus

Influenza is caused by viruses that are scientifically called influenza viruses. In total, there are three different types of influenza viruses: A, B and C. But only influenza A viruses can be really dangerous to humans. Unlike the B viruses, which usually only provoke milder disease courses, and the C viruses, which only occur very sporadically, they are responsible for serious influenza epidemics. They are very versatile and are divided into a large number of subgroups.

These subgroups, which are called H1N1 or H3N2, for example, are divided according to the proteins on the surface of the influenza A viruses, with the help of which the viruses can enter the host cells and subsequently free themselves from them. H stands for haemagglutinin, N for neuraminidase.

If influenza occurs at different times and places, it is called an epidemic. If the wave of the disease crosses countries or even continents, it is called a pandemic. Waves of influenza occur almost every year during the winter season. Every ten to 40 years there is an influenza pandemic, but the severity of the illness can vary. In 2009, 18,000 people worldwide died of “swine flu”.

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