The 14 types of fever (and body temperature levels)

Let's take a look at the types of fever that exist, classifying and ordering them according to their dangerousness.

Fever is one of the most common experiences in the life of virtually every human being with time to develop, and it is linked to a wide variety of health disorders. That is why it is important to understand this phenomenon and to know how to identify the different types of fever that exist.

In this article we will see what types of fever exist according to different classifications, as well as their characteristics and possible dangers for the health.

What is fever?

The fever, the increase of corporal temperature, is given like reaction of the body before an agent identified like pathogenicwith the purpose of eliminating it and activating the immune system.

Thus, fever acts as a sign that something in our body is not going well and also promotes the non-proliferation of germs, since these normally only grow at normal temperatures between 35.5 and 37 °C; we will consider fever when the temperature is above 38 °C, being this valued as urgent when it exceeds 41 °C. Viewed another way, normal human body temperature is considered to be between 35.5 and 37 °C, which may vary according to the subject.

Thus, temperatures between 37 and 38 °C constitute what is known as a febrile fever when it is maintained for 24 hours. If it is higher than 38 °C, it is considered a fever, at 39 °C the fever is classified as moderate, and at 40 °C it indicates an emergency situation.

We say that an individual has a fever when we observe an increase in body temperature, a hyperthermia; this is called fever. is produced in the presence of a possible pathogenic agent, usually an infection.. This increase in temperature signals that our immune system has been put into operation to fight these elements that have "sneaked" into the body; therefore, it works as an alarm to act if we see that this feverish state does not improve, and also as a defensive mechanism to kill certain harmful microbes.

The characteristic symptoms of fever are: headache, muscle pain, chills and drowsiness. In general, a feeling of tiredness a feeling of tiredness and exhaustion..

The types of fever (classified and explained).

There are different types of fever that we will classify according to their intensity, their duration, their time pattern, what causes them and how they started. The classification of fever according to intensity has already been introduced in the previous section. We have: febrile fever if the temperature is 37 to 38 °C, fever from 38 to 41 °C, and hyperpyrexia if it exceeds 41 °C.

We must take into account how we take the body temperature, since depending on the instrument we use it may vary. Thus we can measure it in different parts of the body such as in the mouth (oral), rectum, armpit, ear or forehead. It is considered that the most accurate are those that we take orally or rectally; in the other three, which are more frequent, show less accurate results. For this reason, it will be necessary that when we tell the doctor our temperature we indicate with which measuring device we have taken it.

The following are some of the types of fever that are considered according to the variables mentioned above.

1. Types of fever according to their duration

Depending on the course and duration of the fever we speak of three types of fever

Acute fever

As its name indicates, this is the fever that lasts less time, less than 1 week, this will be the fever that lasts less time, less than 1 week. The usual causes of this type of fever are viral or some type of infection, this type of fever usually reaches higher temperatures or worsen as the day goes by, higher temperature during the night. Examples of acute fever can be skin, respiratory or urinary infections.

1.2 Subacute or prolonged fever

We speak of subacute fever when the subject is more than 1 week with fever, but does not exceed 3 weeks.. This type of fever is linked to bacterial infections, examples of which could be enteric fevers such as typhoid.

1.3 Chronic fever

Chronic fever exceeds 3 weeks of symptomatology. It may be due to one of the previous fevers (acute or subacute) that have not been cured, or to some type of infection with chronic involvement, such as HIV or tuberculosis.

2. Type of fever according to the pattern

Depending on the temporal pattern of fever periods, we differentiate between four types.

2.1 Intermittent fever

As its name indicates, this type of fever varies throughout the day, during 24 hours, with periods of fever and periods of fever.There are periods of fever and others without elevated temperature. Examples of this type of fever are abdominal abscesses, caused by a pocket of pus or malaria.

Within the intermittent fevers we find heectic or septic feverThis is characterized by a great difference in temperature between fever and non-fever periods; it is usually due to septic processes where there is a dysfunction in the organs due to a dysregulation of the infection.

On the other hand, we also find daily feverwhich exhibits a regular daily episode of fever and is typically caused by some species of Plasmodiumwhich is a type of protozoan (for example, malaria can be classified within this type).

2.2. Remitting fever

In the remittent type of fever the high temperature remains permanently high, without reaching normal levels during the day, but variations of more than 1 °C do occur.. An example could be brucellosis, a type of bacterial infection that is transmitted from animals to humans, being common when eating raw or unpasteurized dairy foods.

2.3. Continuous fever

In the case of continuous fever, it is similar to the previous type of fever, i.e., the high temperature is maintained throughout the day, but in this case there are no large oscillations, the difference between maximum and minimum temperature is not greater than 1 °C.The difference between maximum and minimum temperature is no more than 1 °C. A disease that can present this pattern of fever is pneumococcal, which results in a serious infection by bacteria, specifically by Streptococcus.

2.4 Relapsing fever

Recurrent fever, also called relapsing, periodic or undulating fever, alternates between periods of fever and periods without fever. This definition may be similar to intermittent fever, but unlike intermittent fever, where the variation occurs at an interval of 24 hours, in recurrent fever the interval of variation is larger..

Thus, after a period with normal temperature, the fever reappears and another type of pattern of those already mentioned may then occur. Within the recurrent fever, two types can be distinguished: pel-ebstein fever, which is characterized by being infrequent and presenting a pattern of 3 to 10 days with fever followed by 3 to 10 days without fever and so on continuously, and tertian, quartan and quintan fever, in these types there are febrile intervals followed by two (tertian), three (quartan) or four (quintan) days with normal temperature.

Type of fever according to its cause

As mentioned above, the increase in fever is due to the appearance of a pathogenic agent that activates the immune system, so there may be different causes.

Fever due to infection

Fever due to infection is the most common cause.It can occur in different parts of the body and can be cutaneous, gastrointestinal or throat.

The increase in temperature is beneficial, since it helps the immune system to become active and function more quickly and, on the other hand, most infectious agents develop at normal temperatures between 36-37%, ceasing to proliferate if there is an increase in temperature.

3.2. Fever due to autoimmune involvement

In the autoimmune type of fever the increase in temperature is due to the immune system's misinterpretation of its own cells, which are not recognized as such.The immune system does not recognize them as such and for this reason attacks them. An example is lupus which, among other symptoms, produces fever without any known cause.

3.3. Oncological fever

In this case the increase in temperature and activation of the immune system is due to the detection of a tumor. is due to the detection of a tumor that the body interprets as a pathogen and increases its action to eliminate it. and increases its action to eliminate it.

3.4. Vaccine fever

The function of vaccines is to prepare and teach the organism, the immune system, how to act in the presence of certain viruses or bacteria. Thus, it consists of the introduction of some fragment of inactive virus or bacteria that normally only generate a mild reaction..

3.5. Fever due to tooth growth

When the teeth begin to erupt it is common for the child to show discomfort and may even produce an increase in temperature and inflammation as a response of the immune system to protect the subject. Normally, the increase in temperature is mild, giving only a low-grade fever..

3.6. Fever as a drug side effect

As a side effect of some drugs, an increase in temperature may appear as a febrile fever or a slight fever, although, normally, if there are no complications, this fever will be mild. If there are no complications, it usually disappears when the drug is withdrawn..

3.7. Fever due to the presence of clots

A clot is a mass of platelets, proteins and blood cells stuck together. When this body forms in the circulatory system and clogs or is in danger of clogging veins or arteries, the body activates the immune system and raises the body's temperature to facilitate removal of the clot. and increases the body temperature in order to facilitate the elimination of the clot.

Fever of unknown origin

In this type of fever, as its name indicates, the cause is not known, since it is not due to any of the aforementioned conditions. If the fever lasts for a short period of time, it will not be a major complication, but if the high temperature persists for more than 3 weeks, i.e. it becomes chronic, the doctor will continue to analyze what may be the cause of such dysregulation.

4. Types of fever according to its onset

Depending on the mode of onset of fever, we differentiate between sudden and slow-onset fever.

4.1. Sudden-onset fever

In this case we observe that temperature rise occurs suddenly.

4.2. Slow-onset fever

A slow-onset fever is when the temperature increase appears progressively.