Fever, also known as hyperthermia or pyrexia, refers to a condition in which the body temperature is higher than normal. Normal body temperature is around 98.6˚F (37˚C).
The temperature of the body may fluctuate through the day, with a low temperature in the morning which gradually increases in the afternoon and evening. In adults, fever is defined as body temperature 100˚F or higher (>37.8˚C).
In children temperature exceeding 99.5˚F (>37.5˚C) is considered as fever. Under normal conditions, an increase in body temperature helps to fight off disease-causing organisms. A fever is the first response or signal of infection in the body and is one of the most commonly diagnosed conditions.
Fever can be categorized as low-grade or high-grade. Low-grade refers to a mild increase in body temperature and often ranges from 100.4˚F – 102.2˚F. A body temperature that goes above 102˚F is categorized as high-grade fever.
Body temperature can be measured using an oral, rectal or axillary thermometer, depending on the location of checking the temperature. An increase in body temperature often accompanies an infection, but may also be seen with physical activity, high external temperature, and wearing thick clothing.
Some of the symptoms that may accompany low-grade fever include:
- Abdominal pain
- Rashes on skin
- Increased frequency of urination
- Pain while urinating
- Redness on skin
- Sore throat
- Difficulty breathing
- Neck rigidity
- Discoloration of lips or nails
- Muscle pain, joint pain, severe headaches, or ear pain
- Diminishing level of consciousness
- Difficulty to perform normal physical tasks like walking
- Irritability in children
- Decreased appetite
- Ear pulling in children
A low-grade fever may affect appetite and cause morning stiffness. Swollen lymph nodes and joint deformity may also be seen along with low-grade fever. Children may show ear-pulling habit.
Fevers frequently come along with infections, and fever is a part of the body’s natural defense system against these infections. The body’s temperature can also rise due to other factors like rigorous physical activities, wearing thick and dense clothes, and other environmental factors like high temperature in the weather.
A low-grade fever can also happen after taking vaccines or immunizations, during teething, or as a sign of cancer or other serious diseases. And it can also happen due to the side effects of some medicines.
A low-grade fever may happen due to several reasons in adults and children such as due to specific infections, long term diseases, or due to some treatments which may weaken your immune system like cancer therapies.
Some of the symptoms that indicate a life-threatening condition include:
- Change in mental condition like lethargy, delirium, or hallucinations
- Pain in the chest or chest tightness
- Reduced frequency of urination
- Rapid heart rate
- Shortness of breath
- Severe pain
- Blood in vomit or stool
- Skin nodules
- Feeling hot without perspiring
Low-grade fever may be caused by infections, physical activity, immunizations, teething, or as a symptom of a serious medical condition.
Infectious causes of low-grade fever include bacterial infections, cellulitis, viral infections like flu, ear infection, gastroenteritis, HIV/AIDS, lung infections, parasites, urinary tract infections (UTIs), and sinus infections.
A low-grade fever is also a symptom of many cancers, inflammatory bowel disease, side effect of certain medications, vasculitis, and pulmonary embolism.
Some serious, potentially life-threatening causes of low-grade fever are an acute liver infection, appendicitis, cancer, diverticulitis, encephalitis, epiglottitis, heat exhaustion, meningitis, osteomyelitis, and pancreatitis.
Diagnosis is based on medical history, signs and symptoms, and physical examination. Information on the onset, factors that worsen or improve fever, chronic medical conditions, recent travel, other accompanying symptoms, and current medications help in identifying the probable cause of the condition. Other tests and investigations are based on the probable cause of the fever.
Medications like ibuprofen, acetaminophen, and aspirin are the most commonly suggested method for treating fever. Serious symptoms should be brought to the attention of doctor for early diagnosis and treatment of the underlying condition.
One should remain well hydrated by having plenty of fluids while having a fever. Good amount of rest also helps to alleviate the symptom. Light clothing and cool room temperature may also be of help during low-grade fever.