Flu Symptoms 2019; 10 Common Signs & Symptoms of Flu


Every year, everywhere, millions and millions of people around the world contract the flu. In fact, The World Health Organization reports that flu epidemics cause anywhere between 3 to 5 million cases of severe illnesses that result in hundreds of thousands of deaths. The flu, although extremely common, is no small thing.

Further complicating this picture is the fact that very often, flu symptomatology is confused with that of the common cold. With the potential for generating such dramatic impact on the state of health of so many individuals, it is imperative that we learn to recognize flu symptoms for what they are, in an attempt to minimize their effects on our bodies.

What is the flu?

Like the common cold, the flu is an acute respiratory disease. However, unlike the common cold, which is caused by several types of viruses, the flu is produced exclusively by the influenza virus. And in contrast to the common cold, whose symptoms develop gradually, the flu arrives suddenly, and its symptoms develop with greater intensity and severity.

Thankfully, the duration of the flu is “self-limiting,” that is, most patients begin to improve after only a few days. However, it can sometimes produce more severe conditions, such as pneumonia. Additionally, in rare cases, the flu has been known to exacerbate pre-existing conditions such as heart disease and diabetes, which can lead to death.

How is the flu spread?

The Influenza virus is spread from a sick individual to a healthy individual through the thousands of microscopic droplets of saliva that are generated with each cough or sneeze. Another highly infectious vector is the one created by the many surfaces that harbor the virus, and that come into daily contact with healthy individuals such as bathroom door handles and common household appliances like TV remotes.

Moreover, when contaminated hands are brought near the face, the Influenza virus is able to enter the new host’s respiratory tract easily. As such, the importance of hygienic practices such as the proper cleaning of hands and covering of the mouth when sneezing or coughing, cannot be stated enough.

In the case of the Influenza virus, the span of time between the moment of infection and the initial appearance of symptoms, also known as the viral incubation period, lasts between one to four days. However, most people become infectious one or two days before the appearance of the first symptoms.

What are the first signs of the flu?

The most notorious fact about the influenza virus is that the flu manifests suddenly and with a high fever of about 38 or 39 degrees. The fever, which is typically accompanied by chills and body aches, lasts about two or three days. Along with the high fever, the flu usually presents with a severe malaise and a sense of fatigue or weakness that can be extreme.

However, many of the symptoms associated with the disease are also present in a host of other viral infections, especially in patients with the common cold. Therefore, it’s highly relevant that we learn to differentiate between the two.

Let us take a closer look at the most common symptoms of the flu and how they compare to their manifestations in patients with the common cold.

Flu symptoms 2019


Any time the body is affected by a viral or bacterial infection, a fever is likely to be generated. The fever, which can be described as a marked increase in the body’s normal temperature range, is a useful defense mechanism that can reduce the presence of infectious agents in the body by increasing the proliferation of T cells and the mobility of leukocytes.

High fevers, which are present in close to 90% of patients with the flu, can reach upwards of 40 degrees Centigrade. In these cases, it becomes crucial to control the temperature, especially in the elderly and young children, because essential body functions can potentially become affected. The common cold, on the other hand, rarely presents with a high fever and only occasionally with a low-grade fever.

In the case of high fevers, follow these tips to lower the temperature:

  • Apply a cold, damp compress to your forehead.
  • Take a bath in lukewarm water.
  • Drink plenty of fluids and when hungry, eat foods that are easily digestible.
  • Take acetaminophen and ibuprofen to help treat discomfort and lower the temperature.


Chills, or tremors, can occur at the beginning of an infection. They are often associated with fevers because of an increase in muscular contractions that occurs when the body attempts to regulate body temperature. Generally speaking, young children tend to have higher fevers than adults do, so chills are especially common in that demographic. It should be noted that “Goosebumps” are not the same as chills. Goosebumps appear on the surface of the skin due to cold air, and in some cases due to strong emotions such as shock or fear. Same as with fevers, chills are rarely seen in patients with the common cold.


Cough is a natural reflex of the body whose primary purpose is to protect the lungs by expelling infectious secretions. In other words, the cough reflex can help to clear the airways of the respiratory system of excessive mucus, which helps to fight off infections.

A cough can be productive or non-productive. More specifically, a productive cough generates mucus, while a non-productive cough does not. The duration of the cough depends primarily on its causes. Acute coughs, like those caused by the common cold or influenza infections, typically last no more than three weeks. Furthermore, the common cold only occasionally produces a mild to moderate cough; however, the flu is likely to produce a dry cough that can be very intense.

Sore Throat

When the throat or pharynx becomes inflamed as a result of viral or bacterial infection, patients experience a sore throat. Sore throats cause significant pain and discomfort when swallowing or talking. Sore throats are commonly observed in patients infected with the common cold and, less frequently so, in patients with the flu.


Sneezing can be a symptom of an infection or an allergy and is the result of inflammation of the trigeminal nerve of the nose. Sneezing functions as a defense mechanism in which air is abruptly expelled through the nose and mouth in order to rid the various mucous membranes of the respiratory tract of irritating particles.

It is important to note that while sneezing can protect the body from infectious agents, it also dramatically increases the infectious potential of the disease by contaminating the air with microscopic droplets of saliva loaded with viruses and bacteria. Sneezing is quite frequent in patients with the common cold but only sometimes observed in patients with the flu.


Rhinorrhea is the excessive buildup of mucous fluid inside the nasal cavities. Rhinorrhea is caused by bacterial and viral infections, as well as by allergic rhinitis or sinusitis.

The mucus generated by the flu is thick and abundant and has the potential to reach the lungs where it can complicate the prognosis. In the case of the common cold, rhinorrhea is extremely bothersome, and continually generates discomfort in patients who must constantly clear their nasal cavities of thin and clear mucus.

In both cases, the abundance of mucus has the potential to lead to further inflammation of the airways, as well as obstruction of the various nasal passages.


Headaches that accompany viral infections, such as the common cold and the flu, usually have the same duration as the disease. Although In some cases, the duration of the headache can extend beyond the duration of the infection. Headaches tend to be mild in patients suffering from the common cold, and tend to be much more intense in patients with the flu.

Additionally, there are cases in which the flu can produce more severe complications such as sinusitis. Sinusitis, which is the inflammation of the mucosa that lines the paranasal sinuses, is highly painful. The paranasal sinuses, are a group of four air-filled passages that are located behind the nasal cavity, and can be divided into: The frontal sinuses, located on the front of the skull and above the nose; the sphenoid sinuses and ethmoid air cells, located on the sides of the nose; and the maxillary sinuses, located in the cheeks.

In healthy patients, air passes through the sinuses without a problem; however, people suffering from sinusitis frequently suffer from obstructions of these sinus passages, which creates significant discomfort and difficulties when breathing, as well as Sinus Headaches.

Flu patients have been known to experience Sinus Headaches, which are headaches that are caused by obstruction of the paranasal sinuses. These headaches are characterized by a feeling of intense pressure around the eyes, cheeks, and forehead. Often, the pain worsens when the patient leans forward or lies down.


Myalgias consist of variable intensity aches or pains that can affect one or more muscles of the body. Ligaments, tendons, and fascia may also be involved. The causes behind the appearance of myalgia are incredibly varied and run the gamut from muscle fiber overload and injury to the presence of certain diseases in the body such as the common cold, the flu, and other respiratory tract infections. Myalgia experienced by patients with the common cold tends to be typically mild; however, patients with influenza habitually experience intense, and debilitating muscle pains.


Fatigue is common prodrome of both the common cold and the flu. Fatigue is a feeling of extreme and persistent tiredness. The flu can make patients feel tired and exhausted, primarily when several other symptoms are affecting various systems and functions of the body. Occasionally, fatigue may persist for weeks after all other symptoms have disappeared.

Fatigue is very common with the flu; this is because the immune system must spend significant amounts of metabolic energy in the fight against the influenza virus. In cases of the common cold, fatigue may be present but to a lesser degree of intensity.


Digesting food requires a considerable amount of energy, and the body will often divert some of this energy towards the immune apparatus during bouts of infection. Additionally, some people develop vomiting and diarrhea, although this is more common in children than in adults. Therefore, loss of appetite is common in flu patients, especially if they have developed these additional symptoms that affect the digestive system. However, the healing process will require energy and nutrients; as such, if inappetence prevents the patient from eating any food whatsoever, it becomes crucial to seek immediate medical attention.


flu symptoms
Flu Symptoms

How to prevent the flu?

Doctors have developed a seasonal vaccine against the influenza virus that is applied annually, and that is recommended for all people. Every year, millions of dollars are spent conducting campaigns to inform and protect at-risk populations from the flu. At-risk populations include the elderly, young children, and immunosuppressed patients. Vaccination against influenza is also strongly recommended for all health professionals because they are significantly more exposed to infection.

Barring the use of the vaccine, influenza can be prevented by practicing basic hygienic measures, such as frequent hand washing, and common sense practices such as proper disposal of tissues and covering the mouth and nose when coughing and sneezing.

Treatment and prognosis

Most people are able to recover without any special therapeutic treatment, except for the use of antipyretics to lower fever and sufficient bed rest. In extreme cases where patients are at risk of developing severe complications, the use of antivirals can be used to treat the infection. However, it is hardly ever necessary. In the case of the flu, bed rest and hydration remain the most important therapeutic options for treatment during bouts of the disease.


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Dasaraju, P. V., & Liu, C. (1996). Infections of the respiratory system. In Medical Microbiology. 4th edition. University of Texas Medical Branch at Galveston.