Recognizing early signs of sickness can help you stay safe. Both doctors and people who know what to look for can recognize warning signs.

Often these early symptoms are physical, such as back pain or muscle aches. But some mental health conditions can have physical indicators as well. These are called pathognomonic signs.


If you have a fever, your body’s immune system is working overtime to fight off infection. Fevers are actually a good thing. The medical community believes that the fever raises your body’s’set point’ to a higher level, which helps kill germs that cause illness.

Usually, a temperature above 100.4 degrees Fahrenheit (38 degrees Celsius) is considered to be a fever. The easiest way to determine whether you or your child has a fever is by using a thermometer. Most doctors recommend taking your own temperature with a digital thermometer, but an oral or rectal thermometer will also work.

Some people can tell when they have a fever by how they feel, but this is not always accurate. People who are shivering, have chills or feel like their teeth are chattering are likely to have a fever. If you’re not sure if you have a fever, ask your doctor for advice.

Many kids get fevers and most of the time they recover on their own within a few days. However, you should call the doctor if you or your child:

Has a fever that lasts longer than three days. Has a fever accompanied by severe headache, throat pain or sinus pain. Has a fever that is followed by shivering or chills, confusion or hallucinations, neck stiffness, or vomiting.


Chills (or shivering) are your body’s attempt to raise your internal body temperature. When your immune system detects an infection, it sends chemical signals to reset the “thermostat,” telling your muscles to tense and relax in rapid cycles, which generates heat through the shivering. Chills are often associated with fever but they can also occur without one.

A chill may come on suddenly, with a feeling of coldness and a shivering sensation. If the shivering is severe, it is called rigor and can be accompanied by teeth-chattering shaking. It’s important to recognize chills and call your doctor if they appear along with fever, sweating, nausea and vomiting or body aches.

Some conditions, such as menopause or low blood sugar levels, can cause chills. However, it’s likely that your body is responding to an infection, such as malaria or a mosquito-borne illness like Lyme disease, when you experience chills.

It’s important to recognize chills as early signs of sickness because they often indicate an infection or a systemic illness that needs treatment.

Generalized Muscle Aches

If you’re working out hard, stretching, and hydrating properly, muscle aches aren’t usually anything to worry about. However, when you feel all the muscles in your body ache, this is not normal and may be a sign of illness or an infection. If you’re experiencing these symptoms, get a medical symptom tracker and reach out to your primary care physician for a medical evaluation.

While generalized muscle aches aren’t a typical symptom of the flu or COVID-19, they could be a sign of another disease, such as an autoimmune condition like lupus. These conditions cause the body to attack itself, which can lead to all-over pain and other symptoms like fever and chills.

In other cases, the muscle aches may be related to a medication side effect, such as statins or antibiotics, which can have widespread effects in the body. In these instances, a doctor will likely need to run tests to determine the root of the issue and recommend treatment options, which may include antiviral, antifungal, or antiparasitic medications.

In some cases, a doctor may also suggest lifestyle changes or a variety of over-the-counter or prescription medications, including nonsteroidal anti-inflammatory drugs (like aspirin and ibuprofen), acetaminophen, and even steroids or disease-modifying anti-rheumatic drugs, depending on the diagnosis. In the meantime, be sure to stretch before and after exercise, stay hydrated, and rest often. This will help to alleviate the discomfort. In addition, it’s a good idea to avoid smoking or drinking alcohol as these habits can contribute to a higher risk of getting an infection.


Headaches are one of the top reasons people miss work or school, but not all headaches require emergency treatment. The best way to recognize an early sign of sickness is to see your doctor for a complete medical evaluation and diagnostic testing. They will ask you about your medical history and conduct a physical exam and neurological exams. Some tests will include blood chemistry, MRI, and skull x-rays.

A common headache is caused by tension in the muscles and blood vessels of the neck and head. These headaches are also triggered by changes in hormone levels during the menstrual cycle, pregnancy, or withdrawal of certain medications like birth control pills or hormone replacement therapy. The pounding, intense pain of migraines can last a few hours and are often preceded by visual auras, nausea, and vomiting. They usually occur on one side of the head and are accompanied by autonomic symptoms on the same side like a droopy eyelid or runny nose. Migraines can have episodic and chronic forms with attacks on a daily basis or recurrence of them over time.

Sinus headaches, which result from sinus inflammation, can be similar in appearance to a migraine, but the pain is more constant and does not usually accompany a loss of balance or vision. The discharge from the sinuses is a yellow or green color compared to the clear discharge in migraines and cluster headaches.

The most dangerous headaches are caused by increased intracranial pressure from a tumor, infection, or bleeding in the brain (hemorrhage). If your symptoms are severe and you experience vomiting, changes in vision, stiffness in your neck, or confusion along with your headache, call triple zero and seek emergency care immediately.


Vomiting is a natural way the body gets rid of substances that are harmful to it. It is often triggered by an irritant that reaches the stomach and upper digestive tract.

People may also vomit from an overly full stomach, motion sickness or stress vomiting. Some people have chronic vomiting caused by gastric motility disorders or anatomic obstructions. In contrast, a sudden and prolonged episode of vomiting that is not associated with any other systemic symptoms might be a sign of a life-threatening condition such as sepsis.

When a person experiences vomiting, they can quickly become dehydrated and lose essential fluids. It is important for them to drink plenty of clear liquids or oral rehydration solution, sipping slowly. Avoid fruit juice, cordials and sugary drinks because they can make the nausea worse. Medications called antiemetics can help ease nausea and vomiting. Examples include metoclopramide, domperidone and ondansetron. These medications can be prescribed by a doctor for patients undergoing chemotherapy or anaesthesia, and are sometimes used during pregnancy to treat morning sickness.

If you have someone who is throwing up repeatedly, call your doctor immediately. The severity of the vomiting will determine whether they should be seen at an urgent care or ER. For example, if the vomiting is persistent and has been going on for more than 24 hours in adults or 12 hours in children, it might be a sign of a more serious problem such as gastrointestinal tract cancer or hernia. If the vomit contains blood or looks like coffee grounds, seek immediate medical attention as these are signs of a possible esophageal rupture. Similarly, call your doctor if the person is experiencing chest pain or severe stomach pain, blurred vision or confusion, high fever, stiff neck or bleeding from the rectum.