Pyrexiophobia: symptoms, causes and treatment

We know that there are phobias for any stimulus we can imagine. Many of them are considered “rare” phobias, due to their low frequency of occurrence and / or the characteristics of the phobic stimulus.

This is the case with pyrexiophobia, which is an intense, irrational, and disproportionate fear of febrile hallucinations.. In this article, we’ll learn what this particular phobia is, and go over what fever is and what hallucinations are. Finally, we will know the symptoms, causes and treatments of pyrexiophobia.

    Pyrexiophobia: what is it?

    Pyrexiophobia is the phobia of febrile hallucinations. In other words, it seems an intense fear of suffering from hallucinations in feverish states. It is a specific phobia (anxiety disorder), classified as “another type of phobia” according to the DSM-5 (Diagnostic Manual of Mental Disorders).

    When you have a very high fever, hallucinations are sometimes one of the symptoms that can occur. Hallucinations are “objectless perceptions”, that is to say they involve, for example, seeing something that does not really exist, or hearing it, noticing it, feeling it, etc.

    like that, hallucinations can be of different types: auditory, visual, tactile… They usually appear associated with delusions (in psychotic disorders), although this is not the case in fever.


    Hallucinations also appear in other pathologies, this time more serious, because they are mental disorders and not a simple fever. This way, they appear especially in psychotic disorders (Eg schizophrenia). They can also appear in mood disorders (bipolar disorder and depressive disorder) or in cognitive impairment disorder (dementia).

    In the population without mental pathology, although less frequent, hallucinations can also appear, in very stressful situations. It is generally a more “physiological” type of hallucination; more precisely, we are talking about hypnagogic and hypnopomic hallucinations. The former appear when we enter a state of sleep, and the latter, when we wake up.

    However, in pyrexiophobia, fear appears only in the face of hallucinations caused by fever.


      The fever consists of an increase in body temperature. This increase is usually temporary and responds to a specific disease, infection, or discomfort. In most cases, a fever is a response to infections.

      What causes fever is a group of substances (endogenous and exogenous) called “pyrogens”. But how exactly does a fever occur? As we said, pyrogens are the causative agents of fever. These substances work in the centers of the hypothalamus (more precisely, in the centers called “thermoregulators”), increasing their temperature.

      When can you tell he has a fever? In the case of children, fever is considered to occur when the temperature is equal to (or higher) than:

      38 degrees Celsius (38 ºC): if measured in the buttocks 37.5 ºC: if measured in the mouth 37.2 ºC: if measured under the arm (armpit)

      In adults, they are considered to have fever when the body temperature is between 37.2 ºC and 37.5 ºC.

      Very strong fevers: hallucinations

      As we said, hallucinations appear when the fevers are very high. We are talking about temperatures that can exceed 41 ° C. This type of fever is usually not caused by an infection, but by an alteration of the central nervous system (CNS).

      When the body temperature is so high, the body may be damaged. In addition to hallucinations, other symptoms appear such as confusion and drowsiness. The hallucinations that appear can be of different types and intensities.

      On the other hand, if the body temperature continues to rise, the damage that the body may suffer is irreversible; in these cases, the proteins eventually lose their structure. Finally, when a temperature of 42 ºC is reached, she falls into a coma, and with 43 ºC death occurs.

      differential diagnosis

      We know that a high fever can cause hallucinations. However, there are other medical conditions that cause high fever and hallucinations, And that we must take into account so as not to confuse the symptoms:


      Encephalitis consists of inflammation of the brain, which in turn can cause irritation and swelling. Usually its cause is a virus. Symptoms of encephalitis include hallucinations and high fever. However, we insist that in pyrexiophobia the phobia only occurs in hallucinations caused by fever.


      Symptoms of pyrexiophobia, as a specific phobia, mainly consist of an intense, persistent and disproportionate fear of hallucinations caused by a high fever.

      Another symptom of pyrexiophobia is avoiding the phobic stimulus; in that case, the person would prevent everyone from suffering from fever (Although this is a difficult situation to control). This avoidance of fever would logically involve avoiding hallucinations.

      Additionally, as with all phobias, there is discomfort associated with the symptoms, which affects the general functioning of the person. This discomfort is clinically significant and interferes with the daily life of the individual with pyrexiophobia.

        the causes

        The causes of pyrexiophobia are linked to previous lived experiences, related to hallucinations caused by the fever itself. In other words, it is likely that the person experienced these hallucinations in a situation of very high fever and experienced the situation as very unpleasant.

        Probably the hallucinations caused him fear, anguish, anxiety or such a degree of bewilderment that the experience ended up being traumatic and causing pyrexiophobia.

        Other possible causes of pyrexiophobia are related to more temperamental or personality aspects; there is another type of people predisposed to suffer from anxiety disorders. They are people with a more precarious, more unstable or “fragile” temperament. In addition, if the person already has another prior anxiety disorder, the risk may also increase.


        Pyrexiophobia is treated like a specific phobia that it is. The main (and most effective) psychological treatment indicated for specific phobias is exposure therapy.. Thanks to it, we can expose the patient to more and more anxious situations and closer to the phobic stimulus.

        In the case of pyrexiophobia, since it would not be ethical to induce a feverish state or induce hallucinations by drugs, one may choose to expose him to symptoms similar to these states. This can also be done through a virtual reality exhibition or through a symbolic exhibition (through videos).

        The aim is that the patient, as far as possible in this case, experiences / feels the symptoms that cause him so much anxiety (hallucinations) and the intense fear associated with them disappears.

        Cognitive techniques can also be used that allow the patient to have a more realistic view of the stimuli of which he is so afraid, understanding that these should not cause him harm. It is important that you understand that high fevers only appear in extreme and infrequent cases, that often it cannot be controlled or predicted, and that in the event that they do occur, any hallucinations you may experience do not occur. will not harm either.

        Ultimately, fever is an adaptive response of the body that alerts us that “something is wrong” (coupled with hallucinations, which can hardly be avoided) and it must. be transmitted to the patient, to reduce the catastrophic and pessimistic thoughts associated with pyrexiophobia.

        Bibliographical references:

        • American Psychiatric Association -APA- (2014). DSM-5. Diagnostic and Statistical Manual of Mental Disorders. Madrid: Panamericana.
        • Escoto, MA (2019). Encephalitis. KidsHealth for parents.
        • Ortega, M. (2018). How does fever come about? Hospital Clínic de Barcelona. Clinical portal. BBVA Foundation.

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