It will arrive without warning, it will mess up everyone’s plans and it will transform even the most rational of adults into a detective struggling with the thermometer. There fever: an unwelcome companion of the winter months, it often remains an enigma even in the golden age of medicine. Thirty-seven and six, what to do, you wait? At 38 you go on tachipirina, but it will be influence or Covid? And then if the temperature rises we are all ready to diagnose ourselves with anything, from the new exotic flu perhaps coming from Australia to the latest disease we read about in the newspapers: what if that strange virus that she caught had arrived here too? Sofia Goggia in Argentina?
When faced with fever, fear is a bad advisor, just like underestimation. And if once upon a time there were family doctors who visited homes and recommended “milk, bed and wool” (treatments, it must be said, which were often not conclusive), today the situation is much more complicated. Because a feverish rise can be many things, and many are not simply seasonal colds: in a globalized society where an intercontinental flight transports a colony of mosquitoes all over the world, fever speaks a different language, a kind of Esperanto that needs to be deciphered in a more sophisticated way than was done in the past. “Fortunately today we have many more tools than just a few years ago,” he tells Panorama Alberto Benettidirector of the internal medicine-high complexity department of theNiguarda Hospital of Milan. «In the emergency room we use i multiplex swabswhich in the case of suspected fever allow us to simultaneously identify, in addition to influenza and Covid, the respiratory syncytial virus, metapneumovirus and other respiratory pathogens. We also have specific tests for some bacterial infections, such as legionella, pneumococcus and mycoplasma.”
Beyond simple influenza: diagnostic complexity and hidden risks
Not that everyone has to undergo a battery of tests when the thermometer rises, but if the clinical picture requires it, there is the possibility of expanding the investigations. Above all to avoid complications, such as pneumonia which in the last summer months – out of season compared to the collective imagination – affected numerous public figures: from Claudio Baglioni (who had to cancel his Italian concert tour) to Vittorio Sgarbi, still hospitalized, up to the American country singer Travis Tritt, who declared he had contracted the pneumonia without realizing it, only to then “collapse” after two weeks of vague discomfort.
But can you really have pneumonia without realizing it? “It can happen, although generally the disease manifests itself clearly with fever, cough and, sometimes, chest pain: however, not all types of pneumonia have the same severity” he replies Francesco Blasidirector of pneumology atIrccs Policlinico hospital of Milan. «Some forms, caused by atypical pathogens such as mycoplasma and chlamydia, can start with fever and sore throat and develop a cough after two or three days, with symptoms similar to bronchitis. In other cases the picture may be milder, the patient in good health may not realize he has it and only discover it later, perhaps after an x-ray that shows signs of past infections.”
When the clinical picture worsens: sepsis and vital parameters to monitor
Be careful, though. Because there are pneumonias that can evolve seriously, such as those caused by pneumococcus or legionella, and when the infection triggers a systemic response and compromises other organs, a sepsisa sometimes fatal septic shock. «In these cases you need to pay attention to warning signs: mental confusion, worsening of breathing, very rapid or irregular heartbeat, significant drop in blood pressure and reduction in the amount of urine”, continues Blasi. «Profuse sweating associated with a sudden worsening of the general condition should also raise suspicion. If a person with fever presents a sudden change in the usual parameters, immediate medical attention is needed.”
This great diagnostic capacity, also available in emergency departments thanks to the new swabs, most of the time allows patients to be started on the correct treatment path, but must not generate false security: the danger is finding ourselves with patients who are discharged in good condition and then, once home, rapidly worsening, perhaps after pneumonia or a legionella infection. The risks of a “relapse” are high. The latest “famous” case in chronological order concerns the US NASCAR champion Kyle Busch, who died in May after severe pneumonia which resulted in sepsis. Busch fainted while, already convalescent, he was testing a simulator: he died a short time later without ever having regained consciousness. While in December 2025, in Sicily, a man discharged from the emergency room with a diagnosis of pneumonia – but without complications requiring hospitalization – died just two days after returning home.
The unpredictability of the course and the need for continuous assistance
How can this happen? «Each patient is a case in itself, and each infection, both viral and bacterial, can have a trend that cannot be predicted 100%, despite the classifications – the so-called risk scores – allowing us to evaluate them with ever more precision» continues Blasi. «This is why we hospital doctors insist on the fact that, once discharged, any patient must be followed by the general practitioner and local facilities. Infections with fever can be unpredictable and very debilitating.”
Sofia Goggia, who contracted the disease, knows something about it chikungunya virus while she was in Argentina training for the ski season and rushed back to Italy exhausted by the illness. «Chikungunya is a viral infection, transmitted by mosquitoes of the Aedes genus», he explains Antonio Casciodirector of the Infectious Diseases Unit of the Polyclinic of Palermo (a city where, moreover, an emergency is underway due to the detection of legionella bacteria, which has led to the closure of three schools). «Transmission occurs mainly in tropical and subtropical areas, but in recent years we have also observed cases of autochthonous transmission in Italy. It can cause high fever, even above 39 degrees, and joint pain in different parts of the body. In some cases the manifestations can be very severe and last a long time, with complications such as myocarditis and neurological manifestations.” In chikungunya, joint disorders can last for months and become disabling: Goggia said he also had difficulty speaking and walking.
From emergency bells to persistent low-grade fever: how to find your way
This obviously does not mean that temperatures above 38 and a half should always suspect who knows what and rush to the emergency room. «The warning signs that should make us worry are lethargy, intense headache, especially if associated with neck stiffness, and tachycardia», continues Cascio. «If red spots appear on the skin it is a big warning sign: they could be petechiaeskin haemorrhages which in case of fever may be associated with meningococcal infections, sepsis or haemorrhagic diseases. We also remember that they must never be taken antibioticsin case of fever, if you do not have a diagnosis formulated by a doctor”.
Then there is the so-called “low-grade fever”, which fluctuates around 37.5 and continues for weeks. Even if it allows you to carry out normal activities, it is still a sign not to be underestimated. «It can be the indicator of a non-infectious inflammatory process, linked for example to rheumatological diseases or tumor pathologies, responsible for paraneoplastic fevers», specifies Benetti. «However, a persistent fever rise does not automatically mean autoimmune disease or cancer. It is necessary to evaluate the clinical picture, collect an accurate medical history and listen to the patient, investigating any other symptoms. It is from these elements that the need to deepen the diagnosis may emerge.”
High temperatures are never trivial, almost never innocent, and must always be considered as a whole. «Humanity has three great enemies: fever, famine and war; of these, the most terrible is fever.” Thus spoke the Canadian doctor William Osler, one of the fathers of modern medicine, in 1896 during the American Medical Association congress in Atlanta. The world has changed, but his words are still valid.
