What is a fever:
Fever is defined as having a temperature above the normal range. The body temperature will be different according to various measuring methods and some environmental factors. It is usually divided into core temperature and body surface temperature.

1. Core temperature: refers to the temperature of inner parts of the body (e.g. ear temperature or rectal temperature.), which includes heart, brain and other vital organs. It is generally maintained at around 37 °C. When the core temperature is up above 38 °C, it is recognized as fever.
2. Body surface temperature: refers to the temperature of the skin, e.g. measured in the armpit or forehead temperature is suggested to be abnormal when it is over 37.5°C. It may not be accurate because it is easy to be affected by the environment.

1. Infection: This is the most common cause for a fever. The sources of infection include bacterial, viral, fungal, and parasitic infection. Fever can aid in host defense as a standard mechanism of protection. It may also enhance leukocyte phagocytosis and reduce bacterial growth. From the immunology aspect, this can be a key factor to initiate the immune response.
2. Non-infection: e.g. inflammation or immune response and others. Inflammation involves tissue damage (e.g. surgery, multiple trauma and fracture, etc.) and/or cell necrosis (e.g. acute pancreatitis, gout and tumors, etc.), the fever pattern is usually low grade fever (below or equal to 38.8 °C). Immunoreaction includes allergic reactions and autoimmunity, and/or other different causes may include vaccination, endocrine disorders, metabolic diseases, vascular diseases and heat injury.

Common symptoms of fever:

The symptoms of infectious fever are various based on the stage:

1. Stage of onset of fever: Pyrogenic sources (e.g. bacteria, viruses, etc.) cause the body temperature rapidly or gradually increases. The symptoms at this stage include:
   1. Chillness: Muscle contraction through shivering which forcing blood from the outer layer of your skin to inside your body, in order to reduce heat loss through skin and produce heat. At the end of this process, the body temperature will rise about 1~2 °C.
   2. Pale and cold skin.
   3. Thirsty.
   4. Increased breathing rate: If metabolism and CO2 levels increase, the respiratory center is stimulated to increase the rate of breathing.
   5. Increased heartbeat: When body temperature elevated by 1°C, it indicates a 13% increase in the basal metabolic rate.
2. Stage of extremely high temperature of fever: The body temperature reaches its highest level and stays about the same temperature.
   1. Symptoms at this stage include: skin flushing, heated skin, increasing heart rate, increasing breathing rate, thirsty, headache, decreased urine output, dehydration, dry and ruptured skin mucous membranes, general malaise and weakness, and poor appetite. Loss of consciousness and delirium may happen.
3. Stage of remission of fever: While the body temperature returns to normal, there are two situations may occur:
   1. The body temperature gradually decreases and usually reaches the normal range within 2~3 days or 1 week, indicating that the disease is improved.
   2. Sudden drop in body temperature to normal or lower than normal within 12 to 24 hours indicates that the body cannot resist the invasion of pyrogenic sources. The symptoms of this stage include sweating, reduced chills and dehydration.

Principles of care for fever:
According to recent studies, fever is wildly recognized as the body’s natural defense mechanism against infection. The most important thing is to treat the underlying condition, instead of just treating the fever itself. As a result, the treatments of fever should be to improve the sense of comfort, rather than to reduce body temperature.

1. Provide a comfy environment: Adjusting the room temperature, improving air circulation, avoiding direct wind blowing to the patients and keeping the environment comfortable.
2. Adequate water, electrolytes and nutrition: It is suggested for patient to drink more water (3000ml per day for adults) and replenish electrolytes properly, as well as having frequent light meals.
3. Hygiene and comfortable: Adding clothes and quilts in the stage of onset of fever; reducing clothes and quilts, helping them take a bath or change clothes if the patient is sweating in the stage of extremely high temperature of fever.
4. Measure the body temperature every 4 hours: Be cautious of the external factors that will affect the temperature, such as exercise, wearing too much clothes and sun exposure. If the external factors are present, the temperature should be measured again after resting for half an hour.
5. Take a tepid sponge bath (warm bath): The tepid sponge bath has no significant effect on decreasing the body temperature of a febrile individual in recent studies, incidence rates of adverse effects including chills, or goose bumps, and discomfort were higher in tepid sponge bath groups. However, it is advised to control the water temperature at 27°C ~37°C and should spend only 10-30 minutes each time with gently stroke. Stop any time if the individual expresses any discomfort during the process.
6. Using antipyretics: When the cause of fever is uncertain, it is recommended not using antipyretics to reduce body temperature. Because antipyretics may cover the symptoms of the disease, making the disease hard to assess correctly. However, in patients with known chronic diseases, such as heart and lung disease and febrile seizure, in order to avoid deteriorating previous physical disorder. Antipyretics can be used to alleviate the discomfort caused by fever. However, they cannot shorten the course of the disease as well as prevention for febrile seizure.

1. Some cases of viral infections may experience fever for up to a week or even longer period. Those being febrile when returning from an epidemic area should seek medical attention immediately. And proactively inform the medical staff about your history of traveling, occupation, cluster and contact.
2. There is no specific drug for most respiratory or gastrointestinal viral infections. If the infection is not under control, it is very common to have a relapsing fever. However, if patients have a fever of 40 °C or higher and/or a fever lasting for more than 7 days and/or the symptoms become severe, they must seek medical consultation for other special causes.  
3. Ice pillow or cooling patch, etc. can cause local vasoconstriction, which hinders heat dissipation. They are not recommended for using regularly.
4. Long-term exposure to hot and humid environments or outdoor activities is prone to heat injury. Fever caused by heat injury needs to be actively cooled down and seek medical consultation as soon as possible to prevent heat exhaustion. When heat exhaustion occurs, it may worsen or lead to heat stroke and permanent damage to the central nervous system without immediate treatment and cooling.
5. It is strongly recommended to get instant to the hospital or ER, if the fever occur with altered state of consciousness, lethargy, neck stiffness, severe headache, sore throat, skin rash, chest pain, shortness of breath, persistent vomiting, bloody stool, painful urination, swollen feet or the swollen part of the skin with redness or burning sensation.
6. Children should seek medical attention immediately if they have a fever with the following conditions:
   1. Infants under 3 months should seek medical consultation immediately when having a fever.
   2. Complications with jerking movement, eye deviation/gazing, poor mobility or abnormal crying, paralysis of the limbs, and abnormal sensation.
   3. Weakness, difficulty breathing, inability to eat, severe vomiting, headache, purple spots or bleeding spots on the skin.
   4. Continuous fever for more than 2 days or body temperature above 39 °C, and any abnormal conditions.