What are 5 red flag symptoms for your general health?

September 30, 2025 •

5 min read

According to the American College of Emergency Physicians, several warning signs indicate a medical emergency. A 'red flag symptom' is an indicator of potentially serious pathology that warrants prompt medical evaluation. Learning what are 5 red flag symptoms and acting on them quickly can significantly improve health outcomes and even save your life.

Quick Summary

This guide outlines five critical health warning signs that should never be ignored. It details chest pain, unexplained weight loss, shortness of breath, sudden or severe headaches, and changes in bowel or bladder habits. The article emphasizes when to seek immediate medical attention versus contacting a healthcare provider for further investigation.

Key Points

Chest Pain: Crushing chest pain, especially when radiating to the arm or jaw and accompanied by shortness of breath, is a potential heart attack sign and requires immediate emergency care.
Unexplained Weight Loss: Losing 5% or more of your body weight over six months without trying can signal underlying conditions like cancer, endocrine disorders, or chronic infections.
Sudden Shortness of Breath: Difficulty breathing that is sudden, severe, or occurs at rest can indicate a serious issue like a pulmonary embolism or heart failure and demands immediate attention.
Severe, Sudden Headache: An intensely painful 'thunderclap' headache that appears without warning may point to a brain hemorrhage or aneurysm and is a medical emergency.
Changes in Bowel/Bladder Habits: Persistent changes, such as blood in stool or urine, require investigation to rule out serious conditions like gastrointestinal disorders or cancer.
Holistic Context: A single red flag should be viewed in context; the combination of multiple red flags or an increase in symptom frequency raises the index of suspicion for serious pathology.

What Defines a 'Red Flag' Symptom?

A red flag symptom is a clinical sign that signals the possibility of a serious underlying condition that requires prompt medical assessment. Unlike minor, transient ailments, these symptoms are often severe, persistent, or appear without a clear explanation. While a single symptom may not always indicate an emergency, their presence increases a clinician's suspicion of serious pathology. The key is to interpret them within their context, considering factors like a patient's age, other symptoms, and medical history. Knowing how to differentiate between a minor issue and a potential emergency is a crucial aspect of responsible self-care.

1. Sudden or Persistent Chest Pain

Chest pain is one of the most widely recognized red flags, and for good reason. It can be a classic sign of a heart attack or other cardiac event, and swift action can be life-saving. The sensation can be described as a crushing, squeezing, or tight feeling in the chest, which may radiate to the arm, jaw, neck, or back.

Heart Attack: Pain is often accompanied by shortness of breath, sweating, nausea, or lightheadedness.
Pulmonary Embolism: A sudden, sharp, pleuritic chest pain that worsens with breathing can indicate a blood clot in the lungs.
Other Causes: While conditions like acid reflux can cause chest pain, it is always safest to seek immediate medical attention for any new or unusual chest discomfort, especially if accompanied by other symptoms.

2. Unexplained Weight Loss

Unintentional and significant weight loss is a serious red flag, especially when it exceeds 5-10% of your body weight over six months without any changes to your diet or exercise routine. While some people may initially welcome a sudden drop in pounds, it can be a warning sign of a hidden medical issue.

Endocrine Disorders: Conditions like hyperthyroidism can accelerate metabolism, leading to weight loss.
Gastrointestinal Disorders: Digestive issues or inflammatory bowel disease can lead to malabsorption and weight loss.
Cancer: Significant, unexplained weight loss is a known symptom of several types of cancer, including some affecting the pancreas, stomach, or lungs.
Infections: Chronic infections can also contribute to this symptom.

3. Sudden Shortness of Breath (Dyspnea)

Experiencing sudden shortness of breath is a symptom that should never be ignored. It may feel like you can't get enough air or that your chest is tight, and it can be particularly alarming when it occurs at rest or with minimal exertion.

Cardiac Issues: Dyspnea is a sign of heart failure, where the heart struggles to pump blood effectively.
Pulmonary Embolism: This blood clot in the lung can cause sudden and severe shortness of breath.
Asthma and COPD: An exacerbation of these chronic conditions can cause acute breathing difficulties.
Other Emergencies: Difficulty breathing, especially when accompanied by chest pain, nausea, or bluish lips, warrants immediate emergency care.

4. Severe, Sudden Onset Headache

While most headaches are benign, a severe and sudden-onset headache, often described as a 'thunderclap' headache, is a major red flag. These headaches peak in intensity within minutes and can indicate a life-threatening condition.

Stroke/Aneurysm: A thunderclap headache can signal a brain hemorrhage or a burst aneurysm.
Meningitis: Headaches accompanied by a stiff neck and high fever can be a sign of this dangerous infection.
Brain Tumor: New, persistent, or worsening headaches can indicate a neurological issue.
Associated Symptoms: Any severe headache that is accompanied by vision changes, confusion, or speech difficulties requires urgent medical attention.

5. Persistent Changes in Bowel or Bladder Habits

Changes in the body's elimination patterns can be an uncomfortable topic, but they are crucial to monitor. Persistent changes, especially when accompanied by other symptoms, can signal an underlying health problem.

Bowel Changes: This includes persistent diarrhea or constipation, blood in the stool, or a change in stool color or consistency.
Bladder Changes: This includes frequent urination, difficulty urinating, or blood in the urine.
Associated Conditions: These changes can point toward gastrointestinal issues, infections, or serious conditions like inflammatory bowel disease or colorectal cancer.

Comparing Mild vs. Red Flag Symptoms

It's important to understand the difference between typical, less-concerning symptoms and those that signal a potential emergency. This table offers a brief comparison to help guide your decision-making.


Symptom	Mild or Common Presentation	Red Flag Presentation	When to See a Doctor
Chest Pain	Heartburn, muscle strain from exercise.	Crushing or squeezing pain radiating to arm or jaw, accompanied by shortness of breath.	Immediately (Call 911)
Fatigue	Tiredness from lack of sleep or a busy week.	Lingering, constant, and unexplained exhaustion that doesn't improve with rest.	Within a few days (Contact PCP)
Headache	Minor tension headache relieved by rest or OTC medication.	"Thunderclap" headache (peaks in minutes), headache with fever, stiff neck, or confusion.	Immediately (Call 911)
Weight Loss	Small fluctuations due to diet or stress.	More than 5% of body weight lost unintentionally over 6 months.	Promptly (Contact PCP)
Breathing	Mild wheezing from allergies or a cold.	Sudden, severe shortness of breath at rest, accompanied by chest pain.	Immediately (Call 911)

Conclusion

Paying close attention to your body's signals is a critical part of maintaining good health. While it's easy to dismiss minor aches and pains, recognizing what are 5 red flag symptoms that could signify a serious medical issue is paramount. Symptoms such as sudden or persistent chest pain, unexplained weight loss, sudden shortness of breath, severe and sudden headaches, and persistent changes in bowel or bladder habits should never be ignored. Your body's built-in warning system exists to protect you, and heeding these warnings by seeking prompt medical attention can prevent catastrophic outcomes and facilitate timely, effective treatment. When in doubt, it is always best to err on the side of caution and consult with a healthcare professional.

How to Seek Medical Attention

For Emergencies (Call 911 or Go to the ER): Use for sudden, severe, or life-threatening symptoms like crushing chest pain, severe shortness of breath, sudden confusion, or a 'thunderclap' headache.
For Urgent Issues (Urgent Care): Use for concerning but not immediately life-threatening symptoms, such as a high but manageable fever, mild abdominal pain, or unusual bleeding without other severe signs.
For Ongoing Concerns (Primary Care Provider): Use for persistent or unexplained symptoms like fatigue, gradual weight loss, or mild swelling that lasts for more than a few days.

Trusting your instincts and listening to your body can be the first step toward better health outcomes. It is better to have a false alarm than to delay care for a genuine emergency.

Frequently Asked Questions

While many symptoms are concerning, sudden, crushing chest pain that radiates to the arm or jaw and is accompanied by shortness of breath is one of the most critical red flags, as it often signals a heart attack requiring immediate emergency care.

Unexplained weight loss is not always a sign of a serious illness, but it is a major red flag that should be evaluated by a doctor. It can indicate underlying issues like endocrine problems, infections, or cancer and warrants investigation, especially if it is significant and unintentional.

You should go to the emergency room for a headache if it is a 'thunderclap' headache (extremely severe, sudden onset), or if it is accompanied by symptoms like fever, a stiff neck, confusion, vision changes, or difficulty speaking.

If you experience persistent fatigue that doesn't improve with rest or adequate sleep and is unexplained, it's a good idea to contact your primary care provider for an evaluation. Chronic fatigue can be a symptom of conditions like anemia, thyroid issues, or autoimmune diseases.

Red flag bowel or bladder changes include persistent diarrhea or constipation, blood in your stool or urine, or a new and persistent change in habits, especially for those over 50. These symptoms require further evaluation by a doctor.

A fever is not always an emergency, but it can be. In adults, a fever over 104°F, or any fever accompanied by severe symptoms like confusion, stiff neck, or a rash, requires immediate medical attention. A persistent low-grade fever that lasts more than a week without a known cause also warrants a doctor's visit.

Trusting your instincts is crucial. If you feel like something is 'off' with your body and it persists, you should seek medical attention. You know your body best, and a nagging sense that something isn't right can be a warning sign that deserves professional attention.