Fever that won’t go down, not eating, unusual lethargy, getting tired easily… Signs of “infection” that should not be watched at home
Infectious diseases can affect people of all genders and ages. They often do not have fixed, unmistakable symptoms that prove with 100% certainty that an infection is present. However, certain groups of symptoms may raise suspicion that an infection has developed in the body, such as an unusually high fever, not eating, becoming more lethargic, or getting tired easily despite little exertion.
Fever—not eating—lethargy—fatigue These symptoms are warning signs that doctors frequently emphasize: “The sooner you seek care, the sooner you may recover. The longer you wait, the greater the risk of life-threatening danger.” Understanding which symptoms warrant prompt medical attention can help reduce the risk of serious complications.
What is an infectious disease, and why is it more dangerous than you might think?
An infectious disease is an illness caused by pathogens. Patients or their relatives may therefore think it is just a common cold and wait to see how symptoms develop at home. In reality, if the body cannot control the pathogens in time, the infection may spread rapidly and become severe, affecting vital organs.
Symptoms that may indicate “a definite infection” and should be watched closely
Although infectious diseases do not have specific symptoms that are immediately obvious, they can cause groups of symptoms that doctors use as warning signs of a possible infection, especially when several of these symptoms occur together.
1. High fever and chills
A fever caused by an infection often rises suddenly and may reach 39–40 degrees Celsius, often accompanied by chills. This differs from fevers caused by other conditions, which are often low-grade or absent. If a high fever persists for several days or does not come down after taking fever-reducing medicine, seek medical attention promptly.
2. Not eating or an unusual loss of appetite
When the body is fighting pathogens, its systems work harder to build immunity, often causing patients to lose their appetite and eat noticeably less. If this continues, it may lead to dehydration and further weaken the body, making the infection more severe.
3. Becoming lethargic and less alert than usual
Lethargy and moving more slowly than usual are very important signs that are often overlooked. This is especially true in older adults with infections, who may mainly appear more lethargic than usual rather than develop an obvious high fever, as younger people often do. If relatives notice that an older adult at home is speaking less, responding more slowly, or becoming more confused than usual, they should seek medical attention promptly without waiting for a high fever to develop.
4. Getting tired easily and unusual fatigue
Fatigue that occurs despite little exertion, or becoming short of breath more easily than usual, may indicate that the body is using a great deal of energy to fight the infection. It may also be a sign that the circulatory or respiratory system is beginning to be affected.
Why is “the sooner you come in, the sooner you recover” central to treating infectious diseases?
Current approaches to treating infectious diseases follow a clear principle: the sooner the condition is diagnosed and treatment begins, the greater the chance of recovery and returning to normal life.
Doctors can collect samples for testing, identify the type of pathogen, and choose appropriate antimicrobial medication in time, before the pathogens spread and damage other organs.
By contrast, if a patient is left at home with symptoms for too long without treatment, the infection may spread and become harder to control, increasing the risk of death.
Severe infection (Sepsis): when an infection spreads and damages organs
One of the most dangerous complications of an infectious disease is sepsis, which occurs when the body’s response to an infection is so severe that it causes widespread inflammation and progresses to impair the function of vital organs.
The frightening thing about this condition is that it often has no fixed, unmistakable symptoms. Instead, it gradually becomes apparent through abnormalities in various organs, such as:
- Lungs – Rapid breathing, panting, or difficulty breathing
- Kidneys – Reduced urine output or abnormal kidney function, potentially progressing to kidney failure
- Brain – Increasing lethargy, confusion, or reduced alertness; in severe, chronic cases, this may lead to brain atrophy
The good news is that if an infection is diagnosed and treated in its early stages, there is a high chance of preserving the affected organs’ function. However, if an infection is left untreated for too long, existing organ damage may not be reversible. This is an important reason why doctors advise against waiting at home for too long if you suspect that you or someone close to you may have an infection.
When should you take someone to the hospital immediately?
Take the patient to see a doctor without delay if any of the following symptoms are present:
- A fever above 39 degrees Celsius accompanied by chills or heavy sweating, which does not come down within 24 hours
- Rapid breathing, panting, or chest pain when breathing
- Unusual lethargy, confusion, incoherent speech, or greater difficulty waking than usual (especially in older adults and young children)
- Not eating or drinking anything for a prolonged period, putting them at risk of dehydration
- A significant decrease in urine output or abnormal urination, such as painful urination or blood in the urine
- A rash on the body or spots of bleeding under the skin
If any of these symptoms occur, do not wait for all of them to appear. Even just one or two warning signs together with a fever are reason to seek medical attention for an accurate diagnosis.
Ways to reduce the risk of infection in everyday life
Prevention is always better than treatment. Simple ways to reduce the risk of infectious diseases include:
- Wash your hands regularly with soap or alcohol gel, especially before eating and after using the restroom
- Receive all recommended vaccinations as advised by your doctor
- Avoid close contact with people who are coughing, sneezing, or have a fever
- Eat clean, thoroughly cooked food and drink clean water
- Get enough rest so your immune system can function at its best
FAQ: Frequently asked questions about infectious diseases
Q: How is a fever caused by an infection different from a common cold?
A: A fever caused by an infection often rises suddenly to 39–40 degrees Celsius and is accompanied by chills and severe body aches. A common cold usually causes a low-grade fever or no fever at all, and symptoms are generally less severe.
Q: Why don’t older adults with infections usually develop a high fever like younger people?
A: The immune systems of older adults often do not respond to infections as fully as those of younger people, so they may not develop an obvious high fever. Instead, they may become more lethargic, lose their appetite, or become more confused. Relatives should therefore focus on changes in behavior rather than waiting to see whether the temperature rises.
Q: Are a bloodstream infection and sepsis the same condition?
A: A bloodstream infection is one cause that can lead to sepsis, a condition in which the body responds so severely to an infection that the function of organs throughout the body is affected. It is a medical emergency that requires treatment as soon as possible.
Q: Can taking anti-inflammatory medicine at home treat an infection?
A: Anti-inflammatory medicines used to relieve pain and reduce fever do not kill pathogens, so they cannot treat the underlying cause of an infection. Antibiotics, meanwhile, are effective only against bacteria. Taking medication without knowing what type of pathogen is involved may lead to drug resistance and worsen symptoms. A doctor should make the diagnosis and prescribe appropriate medication.
Q: How many days should you wait before seeing a doctor if you suspect an infection?
A: If there are clear warning signs, such as a high fever, increasing lethargy, or not eating at all, do not wait more than 1–2 days. The sooner you see a doctor, the greater the chance of recovery and of preventing complications.
In summary: An infection that should not be overlooked
Infectious diseases may not have symptoms that immediately confirm the diagnosis, but symptoms such as a high fever, not eating, increasing lethargy, and getting tired easily should be taken seriously. This is especially important for older adults, who often show signs of lethargy rather than a high fever.
If an infection is left untreated, it may spread and become severe, damaging vital organs such as the lungs, kidneys, and brain.
The principle to always remember is that the sooner you see a doctor, the greater your chance of recovering quickly and safely. If you suspect that you or someone you love has any of these symptoms, do not wait—seek medical attention as soon as possible for an examination and diagnosis.
