Fever is the temporary increase in body temperature and occurs as a defense mechanism of the body to protect itself from bacteria or viruses responsible for the presence of an infection or disease. Therefore, although fever is a symptom that generates general malaise, chills and headaches, it is considered to be a kind of battle that the body is fighting in our favor and not against us.
The causes of fever can be many , but among the most common are respiratory infections (bronchitis or pneumonia), urinary tract infections, flu, gastroenteritis, and sinusitis. Although these conditions do not pose a greater risk to health when properly treated, it is necessary to monitor temperature levels to prevent fever from turning the outlook into a major complication. For this reason, in this FastlyHealarticle we focus on telling you when to go to the emergency room for fever in adults so that you know how to recognize those situations in which this symptom is dangerous.
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When is fever in adults?
The first thing to know when to go to the doctor for a fever is to recognize which are the elevated temperature levels that indicate that a person has a fever.
Fever in adults occurs when the body temperature, measured in the armpit, oscillates around 38ºC and is considered a mild fever. Between 37ºC and 37.5ºC it is considered a low-grade fever, the tenths that alert us that the body is beginning to combat a threat.
However, it must be taken into account that as the day passes and night falls, the body temperature usually rises one degree, so the diagnosis of fever can vary depending on the time of day. Also, when a woman is in the second phase of the menstrual cycle, her body temperature is normally one degree higher than usual. Physical activity and emotions such as stress, fear and anxiety can also produce normal variations in temperature that should not be considered a fever.
To learn more about fever in adults, you can consult: How much is fever in adults?
Fever in adults: when to go to the doctor?
Fever becomes dangerous when the body temperature reaches 40ºC , at that time you should see a doctor immediately. There are particular situations in which the condition of the person or its symptoms suggest visiting a specialist urgently. Some of the possible scenarios are:
- When the person has a fever for more than 48 hours.
- The fever does not go down with medication or it goes down and soon goes up again.
- Intermittent fever has occurred for a week.
- The person with a fever suffers from a major illness such as heart disease or diabetes mellitus.
- The person with a fever has a rash or bruises on the skin.
- If the person has an autoimmune disease or suffers from HIV.
- If a person with a fever was recently given a vaccine or injection.
In the same way, when the fever produces high levels of temperature, it usually wreaks havoc on the body at a general level, so it is also important to see a doctor if the fever is accompanied by :
- Shaking chills.
- General weakness
- Threw up.
- Diarrhea.
- Drowsiness.
- Tos.
- Lack of appetite.
- Burning when urinating.
- Earache.
- Throat pain.
Go to the emergency room immediately when the person with a fever:
- Seizures
- Loss of consciousness or confusion.
- Difficulty speaking or breathing.
- Severe headache and very high fever.
- Purple color on nails, tongue and lips.
- Dificulty to walk.
- If a rash appears on the skin.
- Stiff neck.
- Refusal to move arms or legs, which may indicate bacterial meningitis .
Fiber in the elderly: when to go to the doctor?
Fever can be a fatal symptom when high temperature levels harm the elderly, especially if they have some type of cardiovascular, neurological, kidney or respiratory disease, since commonly the medication used to treat these conditions further weakens the immune system , increasing the risk of complication in the elderly when they have a fever .
Therefore, unlike fever in adults, when the temperature is higher than 38ºC in the elderly, it is necessary to see a doctor. In general, most cases are treated in primary medicine and hospitalization is not necessary, but it is very convenient to be close to a specialist who controls the temperature more effectively and examines the entire symptomatic picture of the person to prevent further risks.
How to lower a fever in an adult at home
Here are some tips on how to lower fever in adults to relieve discomfort:
- Drink plenty of water to facilitate rehydration.
- Stay in bed and rest.
- Avoid being very warm, using light clothing.
- The room temperature should be comfortable, neither too hot nor too cold.
- A lukewarm bath after taking fever medicine helps to lower your temperature. Cold baths should be avoided or it could lead to shock.
- Avoid using ice or cold blankets.
- Eat liquid foods like soups, they can help prevent the body from becoming dehydrated from fever.
If you want to know more tips, you can read our article How to lower fever in adults at home .
This article is merely informative, at FastlyHeal .com we do not have the power to prescribe medical treatments or make any type of diagnosis. We invite you to see a doctor in the case of presenting any type of condition or discomfort.
If you want to read more articles similar to Fever in adults: when to go to the emergency room? , we recommend that you enter our Immune System category .

I am a Surgeon with a diploma in comprehensive ultrasound and surgical care residency, an area I am specializing in. During the exercise of my profession, I have realized the need for patients to know the diseases they suffer, and I can tell you that a large part of their complications is due to a lack of information. Being a health web writer allows me to transmit my experience, without borders, to all those readers eager for knowledge, educate them in the prevention of diseases and promote a healthy lifestyle.