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What temp is too high for a fever: How high a fever is too high?

Fever | Johns Hopkins Medicine

What is a fever?

A fever is a body temperature that is higher than normal. It usually means there is an abnormal process occurring in the body. Exercise, hot weather, and common childhood immunizations can also make body temperature rise.

What causes a fever?

A fever is not an illness by itself. Rather it is a symptom that something is not right within the body. A fever does not tell you what is causing it, or even that a disease is present. It may be a bacterial or viral infection. Or, it could be a reaction from an allergy to food or medicine. Becoming overheated at play or in the sun can also result in fever.

What are the symptoms of a fever?

Normal body temperature ranges from 97.5°F to 98.9°F (36.4°C to 37.2°C). It tends to be lower in the morning and higher in the evening. Most healthcare providers consider a fever to be 100.4°F (38°C) or higher. High fevers may bring on seizures or confusion in children. It’s not how high the temperature is, but how fast the temperature goes up that causes a seizure.

A fever has other symptoms besides a higher-than-normal temperature. These are especially important when caring for babies, young children, and disabled people. These groups may not be able to express how they feel. Signs that mean fever include:

  • Flushed face
  • Hot, dry skin
  • Low output of urine, or dark urine
  • Not interested in eating
  • Constipation or diarrhea
  • Vomiting
  • Headache
  • Aching all over
  • Nausea

How is a fever diagnosed?

The best way to diagnose a fever is to take a temperature with a thermometer. There are several types of thermometers, including the following:

  • Digital thermometer (oral, rectal, or under the armpit)
  • Tympanic (ear) thermometer (not recommended in babies younger than 6 months of age)
  • Temporal artery (temperature taken across the forehead area)

Taking a temperature rectally is the most accurate method in children under 3 years of age. In older children and adults, take the temperature under the armpit or in the mouth. Talk with your healthcare provider about the best way to take your temperature.

Most thermometers today are digital, but there are some glass thermometers containing mercury still in use. Mercury is toxic substance and is dangerous to humans and the environment. Because glass thermometers can break, they should be disposed of properly in accordance with local, state, and federal laws. For information on how to safely dispose of a mercury thermometer, contact your local health department, waste disposal authority, or fire department.

How is a fever treated?

You can treat a fever with acetaminophen or ibuprofen in dosages advised by your healthcare provider. Switching between giving acetaminophen and ibuprofen can cause medicine errors and may lead to side effects. Never give aspirin to a child or young adult who has a fever.

A lukewarm bath may reduce the fever. Alcohol rubdowns are no longer recommended.

Call your healthcare provider for guidance anytime you are uncomfortable with the conditions of the fever, and remember to contact your healthcare provider any time a temperature spikes quickly or persists despite treatment.

When should I call my healthcare provider?

Call your healthcare provider right away for a fever in a baby younger than 3 months old.

Call right away or seek immediate medical attention if any of the following occur with a fever:

  • Seizure
  • Feeling dull or sleepy
  • Irregular breathing
  • Stiff neck
  • Confusion
  • Purple spotted rash
  • Ear pain (a child tugging on his or her ear)
  • Sore throat that persists
  • Vomiting
  • Diarrhea
  • Painful, burning, or frequent urination

Key points about fevers

  • A fever is not an illness by itself, but, rather, a sign that something is not right within the body.
  • Illness, exercise, hot weather, and common childhood immunizations can make body temperature rise.
  • In addition to an elevated temperature, look for other signs, such as: flushed face, hot skin, low urine output, loss of appetite, headache, or other symptoms of an infection or illness.
  • Once you have determined that the person has a fever, you may treat it by giving acetaminophen or ibuprofen in dosages advised by your healthcare provider.
  • Call your healthcare provider if a baby under 3 months has a fever, or seek immediate medical attention if a fever is accompanied by a seizure, lethargy, irregular breathing, stiff neck, confusion, or other signs of a serious illness.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.

Fever | Boston Children’s Hospital

Your child has a fever if her temperature is 100.4 degrees Fahrenheit or higher.

The body has several ways to maintain normal body temperature. The body responds to changes in temperature by:

  • increasing or decreasing sweat production
  • moving blood away from, or closer to, the surface of the skin
  • getting rid of, or holding on to, water in the body
  • naturally wanting to seek a cooler or warmer environment

What causes a fever?

When your child has a fever, her body works the same way to control the temperature but it resets its thermostat at a higher temperature. The temperature increases for a number of reasons:

  • Chemicals called cytokines or mediators are produced in the body in response to an invasion from a microorganism, malignancy, or other intruder.
  • The body is making more macrophages, which are cells that go to combat when intruders are present in the body. These cells actually “eat up” the invading organism.
  • The body is busily trying to produce natural antibodies which fight infection. These antibodies will recognize the infection next time it tries to invade.
  • Many bacteria are enclosed in an overcoat-like membrane. When this membrane is disrupted or broken, the contents that escape can be toxic to the body and stimulate the brain to raise the temperature.

What conditions can cause a fever?

The following conditions can cause a fever:

  • infectious diseases
  • certain medications
  • heat stroke
  • blood transfusion
  • disorders of the brain

What are the benefits of a fever?

A fever actually helps the body destroy its microbial invader. It also stimulates an inflammatory response, which sends all kinds of substances to the area of infection to protect the area, prevent the spread of the invader, and start the healing process.

What are the symptoms that my child may have a fever?

Children with fevers may become more uncomfortable as the temperature rises. The following are the most common symptoms of a fever. However, each child may experience symptoms differently. In addition to a body temperature greater than 100.4 degrees Fahrenheit, symptoms may include:

  • Your child may not be as active or talkative as usual.
  • She may seem fussier, less hungry, or thirstier.
  • Your child may feel warm or hot. Remember that even if your child feels like she is “burning up,” the actual rectal or oral temperature may not be that high.

The symptoms of a fever may resemble other medical conditions. According to the American Academy of Pediatrics, if your child is younger that 2 months of age and has a rectal temperature of 100. 4 degrees Fahrenheit or higher, you should call your pediatrician. If you are unsure, always consult your child’s physician for a diagnosis.

When should a fever be treated?

If your child is very uncomfortable, treatment may be necessary. Treating your child’s fever will not help her body get rid of the infection any quicker, but it will relieve discomfort associated with it.

Rarely, children between the ages of 6 months and 5 years can develop seizures from high fever (called febrile seizures). If your child does have a febrile seizure, there is a chance that the seizure may occur again, but, usually, children outgrow the febrile seizures. A febrile seizure does not mean your child has epilepsy.

What can I do to decrease my child’s fever?

Give her an anti-fever medication, such as acetaminophen or ibuprofen. DO NOT give your child aspirin, as it has been linked to a serious, potentially fatal disease, called Reye syndrome.

Other ways to reduce a fever:

  • Dress your child lightly. Excess clothing will trap body heat and cause her temperature to rise.
  • Encourage your child to drink plenty of fluids.
  • Give your child a lukewarm bath.
  • Place cold washcloths over areas of the body where the blood vessels are close to the surface of the skin such as the forehead, wrists, and groin.

When should I call my child’s physician?

If your child’s temperature reaches 105 degrees Fahrenheit, this is considered a medical emergency and your child needs immediate medical attention, according to the American Academy of Pediatrics.

Call your child’s physician immediately if your child is younger than 3 months old and any of the following conditions are present:

  • Your child’s rectal temperature is greater than 100.4 degrees Fahrenheit.
  • Your child is crying inconsolably.
  • Your child is difficult to awaken.
  • Your child’s neck is stiff
  • Purple spots are present on the skin.
  • Breathing is difficult AND does not improve after you clear the nose.
  • Your child is unable to swallow anything and is drooling saliva.
  • Your child looks or acts very sick; if possible, check your child’s appearance one hour after your child has taken an appropriate dose of acetaminophen.

Call your child’s physician within 24 hours if your child, 3 months or older, has any of the following conditions present:

  • The fever is 102 degrees Fahrenheit or higher (especially if your child is younger than 2 years old)
  • Burning or pain occurs with urination
  • Your child has had a fever for more than 24 hours without an obvious cause or location of infection.

Call your child’s physician during office hours if any of the following conditions are present:

  • Your child has had a fever for more than 72 hours.
  • The fever went away for more than 24 hours and then returned.
  • Your child has a history of febrile seizures.
  • You have other concerns or questions.

High temperature

High temperature (fever, hyperthermia) is a normal and healthy reaction of the body to an infection – bacterial or viral. Actually, fever is a symptom of a disease, not a disease. An increase in body temperature helps kill the virus or bacteria causing the infection.

High body temperature is considered if it is 38°C or higher. An area of ​​the brain called the hypothalamus regulates body temperature. If body temperature rises above or falls below 37°C, the hypothalamus begins to regulate temperature.

The degree of fever may not indicate how serious the condition is. With a minor illness, such as a cold, a fever may rise, and with a very serious infection, there may be little or no temperature at all. Along with fever, other symptoms are also important.

High temperature symptoms

Light (subfebrile) temperature 37.1-37.9

At a light temperature, a blush appears, fatigue is felt, the body is warm to the touch. There may be a headache. Typically, a person with a mild fever can perform normal daily activities.

Moderate (febrile) temperature (38° to 38. 9°C)

High (pyretic) temperature (39° to 41°C)

At moderate and high temperatures, the heat of the skin is felt to the touch, chills or trembling appear. Because of the feeling of weakness, I want to lie down.

Excessive (hyperpyretic) temperature (41°C or higher)

With excessive temperature, severe weakness is felt, it is difficult for a person to move, appetite disappears. Quite quickly, especially in children, dangerous signs of dehydration appear: rare urge to urinate, pale skin, dry lips, etc.


Common conditions that can cause a high body temperature include:

  • acute respiratory infections,
  • influenza and influenza-like conditions,
  • gastroenteritis,
  • ENT infections (sinusitis, tonsillitis, otitis, etc.),
  • kidney or urinary tract infections,
  • infectious childhood diseases such as chicken pox, scarlet fever, rubella (rubella), whooping cough and rheumatic fever,
  • heat stroke,
  • teething in infants can cause mild low-grade fever, etc.

After vaccination, the temperature may also rise slightly – this is considered a variant of the norm.

Fever diagnosis

Despite the fact that the temperature is easy to measure with a thermometer, the cause of its rise can only be determined after clarifying all the symptoms and previous conditions.

Treatment of fever

Elevated body temperature is part of the immune system’s response to bacteria, viruses, and other pathogens. Helps the body fight infection. However, very high temperatures can sometimes lead to complications.

The most common treatments for fever include over-the-counter over-the-counter medications. Children and teenagers should not take aspirin because it has been linked to a condition called Reye’s syndrome.

To reduce elevated body temperature at home contribute to:

  • drink plenty of water (water, compotes, juices, rehydrating drinks, etc.),
  • bed rest,
  • keeping the room cool,
  • lightweight clothing that does not warm the body.

Treatment of fever in a child

Usually, parents care for their child at home, and pediatricians recommend starting measures to lower the temperature if it has risen to 38.5 ° C. It is safe to alternate between ibuprofen and paracetamol at the age-appropriate dose. In addition to taking children’s pharmaceutical antipyretics in a dosage appropriate for the age and weight of the child, you should:

  • undress the child to the underwear,
  • do not wrap, do not cover with a warm blanket;
  • give the child plenty of fluids;
  • regularly check the child’s condition at night;
  • offer the child light food.

Do not wipe or splash the child with cold water.

Call your pediatrician immediately if your child:

  • is under 3 months old and has a temperature of 38°C,
  • age 3 to 6 months, and temperature 39°C or more,
  • if, in addition to high fever, there are other signs of illness, such as rash, etc. ,
  • high temperature persists for more than 5 days,
  • high temperature in a child is not reduced by paracetamol or ibuprofen,
  • showed signs of dehydration – infrequent urination, sunken eyes and no tears if the child cries.

Fever in an adult

Many causes can cause a high temperature in adults, but most often it means that an infectious agent has entered the body. However, a high temperature can also be caused by non-infectious causes, so it is important to monitor all your symptoms and if the high temperature persists for more than 3 days, you should consult a general practitioner. In addition to establishing the objective cause of the fever, the therapist will recommend an antipyretic.

Temperature at elevated pressure

The simultaneous increase in body temperature and blood pressure often occurs suddenly, without any prerequisites. The most serious diseases that high blood pressure and body temperature can indicate are vegetative disorders, kidney disease, and thyroid dysfunction. In such cases, you should consult a general practitioner.


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the highest temperature a person has

The indicator of a person’s body temperature is extremely important for him. If the norm of 36.6 ° C is violated, it is already possible to start talking about deviations in the body. The higher the temperature, the more you need to worry. Usually the critical measurement limit is 42°C, but the world has recorded a body temperature record that is even hard to imagine.

What is the maximum body temperature recorded in a person

This story took place in Atlanta (USA). The highest human temperature in the world was recorded there. American Willie Jones was admitted to a local hospital with heatstroke. The man’s temperature rose to 46.7°C.

The event is dated July 10, 1980. The man’s condition was assessed as extremely feverish and critically dangerous, but after only a few weeks of hospitalization, he successfully recovered and went home.
What prompted the fever for such a record? As we have already noted, it was a heat stroke. The paradox is that the air temperature that day barely exceeded 32°C with a humidity of 44%. For the residents of Atlanta, this alignment can be called quite familiar. For the inhabitants of the world living in hot countries, this is just a ridiculous temperature. For example, in Thailand, the mark often exceeds 35 ° C with a humidity of 90%. It is possible that Willie Jones was engaged in intense physical activity on the street, which is why he suffered.

What determines the temperature of the human body

The temperature of 36.6°C is set as normal for a reason. Back in the 19th century, the German physician Karl Wunderlich measured the indicator in the armpit region about a million times in 25 thousand patients. So the average value was derived, the deviation from which up or down is still a deviation from the norm. Yet modern standards make amends to allow that human body temperature can range from 36°C to 37.4°C.

It is now known that various factors, including age, can have an impact on this indicator. For example, a mark above 36.6 ° C in a child is quite normal. For older people, the temperature can reach lower values.
A high fever in children can be due to a number of factors. For example:

  • warm clothes;
  • nervous excitement;
  • eating;
  • bathing in warm water.

That is why, if the child is under 1 year old, the temperature regime should be closely monitored. After waking up, these figures become noticeably lower. If the child begins to actively play, the temperature will rise.

Does the temperature depend on the environment

There are many places in the world where the body can be very hot or very cold. Do not forget about the zones of sharply continental climate. Often the biggest challenge for athletes is acclimatization. In high mountains, the value of temperature indicators can change dramatically, creating a heavy burden on the human body.

Our organism is warm-blooded, able to maintain the temperature value regardless of environmental conditions. However, the case of Willie Jones showed that heat stroke can cause severe harm. The human body itself cannot endure strong temperature loads, therefore, literally 2 ° changes already negatively affect the body. Confusion, dizziness, malaise and other symptoms appear.

Often, when this value increases, people remember diseases. Indeed, the activation of the immune system leads to a flurry of chemical reactions, which causes a high temperature. So our body creates “uncomfortable” conditions for the pathogen to destroy it.

What types of temperature indicators are divided into

It should be noted that not every temperature is high. In medicine, there are clear boundaries that indicate a condition. The lowest limit starts from 37°C to 38°C. It is commonly called subfebrile. Febrile starts from 38°C to 39°C. High is considered to be the border exceeding 39 ° C. The most dangerous value starts from 40°C.

Doctors operate with borders when making a diagnosis. Note that these indicators are not the most important in determining the state. Other symptoms play a big role. A high temperature value does not at all indicate a dangerous disease – there are many examples in the world when people were in a state of fever, but there was no serious threat to their lives.

A persistent temperature reading above 37°C and below 37.5°C may indicate the occurrence of processes associated with serious diseases.

Can temperature fluctuate

As we have already noted, temperature fluctuation is a natural process and depends on age. Especially often fluctuations occur in a person when they reach adolescence up to 18 years. Fluctuations can be influenced by a variety of factors, physical activity always has a great influence.

It is important to know that high temperatures may not be related to nutrition, strenuous exercise or inflammation at all. Many cases are recorded in the world when a person who stays for a long time in a stuffy room or in the heat is unable to lead a normal life. This is due to the fact that his body has received a large temperature load and cannot restore normal heat transfer. This is how heat stroke begins. The consequences of this condition most detrimentally affect the brain.

Temperature values ​​during pregnancy

In pregnant women, the state of the organism is greatly influenced by the hormonal background. High temperatures are due to sharp hormonal surges, so you need to constantly measure temperature indicators. However, with prolonged exposure to even subfebrile temperatures, there is a reason to consult a doctor, since such a condition can pose a great threat.

What instruments measure temperature

There is a wide variety of instruments for measuring body temperature in the world. Thermometers are still one of the most popular products, so global manufacturers offer a variety of models.
The most famous type of thermometers in Russia is mercury. This thermometer is characterized by high accuracy, affordability and is still in great demand. However, there are not as many such thermometers in the world as they used to be, because they are quite fragile and pose a danger. The mercury they contain is poisonous. A high degree of its deodorization is dangerous and can harm humans and animals.

Electronic thermometer has become more popular in the world. Their most interesting feature was the ability to measure indicators in just 30 seconds. As soon as the measurements are completed, the device will notify you with a sound signal. Alas, such devices do not give exact values. Therefore, manufacturers of such thermometers indicate an error in the instructions. Nevertheless, all over the world they have gained the greatest popularity.

The most modern type of thermometers in the world are infrared. With their help, you can measure the index without contact, getting results in just 5 seconds. The error of this type of thermometer is very low and is no more than 0.5 ° C. A characteristic feature of the infrared thermometer was the limited application. It can read data only from a certain area, for example, a temple, forehead or ear. Moreover, the coverage is purely single, so if the device is designed to measure on the forehead, then it will be impossible to measure in another zone.

Now thermal strips are spreading all over the world. They are widely used due to their ease of use. Such a strip can be applied to the forehead and in a minute it will show the result. The definition occurs along the borders, which helps to find out the most necessary information. Because of this, thermal strips cannot replace a full-fledged thermometer.

What are the forms of temperature fever

Pink (red) fever, which is not always familiar to everyone, is a dangerous signal. She declares herself by redness of the skin, a characteristic blush on her cheeks. With red fever, the body is able to function quite normally and provide proper heat transfer.

The most serious danger is white fever, which is recorded relatively rarely. It can be caused by vasospasm. With white fever, failures of processes associated with thermoregulation occur. The skin becomes white, while the hands get cold, and the thermometer shows a high temperature level. White fever is very dangerous because the heat can harm the internal organs.

What are the consequences of a high temperature

There are 3 symptoms that make themselves felt when you have a high temperature. These are nausea, pressure and diarrhea. The second should be concentrated separately. Fever affects hemodynamics, which leads to increased heart rate. The acceleration of blood flow leads to vasodilation and an increase in blood pressure. At the same time, the indicators, as a rule, do not exceed 140/90 mmHg An increase in pressure is characteristic of people who have a fever of 38.5 ° C. Sometimes the pressure may, on the contrary, decrease. You should not take drugs that affect blood pressure, as the indicators will even out on their own after the fever passes.

Anyone who suffers from hypertension should be seriously alert, because even a slight increase in temperature can lead to big problems. Those suffering from hypertension should take antipyretics. You also need to be careful for everyone who suffers from arrhythmia, atherosclerosis, diabetes mellitus, heart failure.
If low pressure is fixed at a high temperature (especially the subfebrile range), then pathology may occur. You don’t need to be scared in advance, you just need to undergo a full examination.

Can fever occur without other symptoms. If there is an increase in temperature, and there are no other symptoms, you should immediately go for a medical examination.