What does Atypical Mean?

The atypical adjective qualifies that which, due to its properties or characteristics, is different from the common types or the models that represent the elements of its class. The concept of atypical can be linked to ideas such as strange, weird, irregular or extravagant.

For example: “I do not understand why the dog reacted in that way: it is something atypical”, “It will be an atypical tournament since, for the first time in history, thirty teams will participate”, “It is an atypical summer, with temperatures that are kept below 20º ”.


The atypical is what escapes the ordinary. Suppose that a man, when leaving his place of work, usually goes home without exception and usually arrives between 6 and 7 p.m. If one day at 9 pm you still have not returned home, it is probably an atypical situation. So it would be understandable that if you haven’t talked about a change in plans in advance, your family starts to worry about the excessive delay.

The notion of atypical also appears in various sciences and disciplines. In the field of statistics, we speak of an outlier with reference to an observation that, compared to the other data collected, is numerically very distant. If in a sample of 100 people, 99 individuals measure between 1.50 and 1.85 meters and a subject measures 2.20 meters, this last value can be marked as atypical.

For medicine, on the other hand, an atypical pneumonia is a type of pneumonia (disease that affects the respiratory system) that does not have its origin in the usual pathogens.

First of all, it is necessary to mention that typical pneumonia is the swelling or inflammation of the tissue of the lungs that occurs when a germ causes an infection. In the case of the atypical one, the infection is caused by another type of bacteria. Although it may seem otherwise at first glance, the symptoms of the latter are usually milder than those of the former.

Before detailing the symptoms, it is necessary to delve into the causes, which in this case include the attack of three different types of bacteria:

* Mycoplasma: causes homonymous pneumonia, which usually affects individuals who have not yet reached 40 years of age;

* Chlamydophila pneumoniae: this type of atypical pneumonia can appear at any time of the year;

* Legionella: it occurs very frequently in adults or the elderly, with immune problems, chronic diseases or with tobacco addiction. It is known as Legionnaires’ disease.

Atypical pneumonia caused by the first two bacteria is usually mild, while the third presents a curve characterized by an increase in severity during the first six days, followed by an improvement that can take up to five days. Among the most common symptoms are chills, cough (in the case of Legionella pneumonia, it can include blood and mucus), fever of varying intensity, and problems breathing normally (especially when exerting).

On the other hand, we have a series of symptoms that do not appear as frequently, among which are: chest pain (becomes more severe when coughing or deep breathing), confusion (especially in elderly people), headache, lack of appetite, fatigue, stiff joints, muscle aches and sweating. Less common are: diarrhea, pain in the eyes and ears, lump on the neck, and rash.

Atypical pneumonia patients should undergo a complete evaluation by the physician, followed by a chest X-ray to rule out other respiratory infections, such as bronchitis.