Cold, Flu, or COVID? How to Tell the Difference

Your throat's scratchy, you're exhausted, and you've got a headache that won't quit. You're pretty sure you're getting sick, but here's the question: what exactly do you have? A cold? The flu? COVID?

These illnesses share so many symptoms that figuring out which one you're dealing with feels like guesswork. And honestly? Sometimes it is.

Here's what I want you to know: the overlap in symptoms is real, the confusion is valid, and knowing which illness you have can actually change how we approach your care.

Why Symptom Overlap Makes Everything Confusing

Let's look at what makes this so tricky. Fatigue? It could be any of the three. Headache? Same story. Cough, body aches, sore throat—these symptoms show up across cold, flu, and COVID-19, making it nearly impossible to know what you're dealing with based on how you feel alone.

This isn't just frustrating when you're trying to decide whether to stay home from work or school. It matters because these illnesses can require different approaches to treatment and have different implications for the people around you.

To help visualize just how much these illnesses overlap—and where they differ—this comparison chart from Healthline breaks down the most common symptoms across all three conditions:

As you can see from the chart, many symptoms appear across multiple illnesses, which is why distinguishing between them based on symptoms alone is so challenging. However, certain patterns in how these symptoms present can offer important clues.

The Patterns That Can Point You in the Right Direction

While there's significant overlap, certain patterns can offer clues about what you might be experiencing.

Colds typically start gradually. You might notice a scratchy throat one day, then congestion the next. Sneezing and a runny or stuffy nose are the hallmark symptoms. You'll probably feel tired and might have a mild headache, but you're usually not completely knocked off your feet. Fever is uncommon with colds in adults.

Flu tends to hit suddenly. You feel fine in the morning, and by afternoon, you're in bed with a fever, body aches, and exhaustion that makes even sitting up feel like too much effort. High fever (often above 101°F), severe body aches, and that overwhelming fatigue are the calling cards of influenza. Respiratory symptoms like cough and congestion usually develop after the fever and body aches start.

COVID-19 can look like either a cold or the flu, which is part of what makes it so challenging. Some people have mild symptoms that feel like a common cold. Others develop high fever, severe fatigue, and respiratory symptoms similar to the flu. The distinguishing factor that became well-known early in the pandemic—loss of taste or smell—is less common with current variants but still occurs more frequently with COVID than with cold or flu.

Managing Symptoms at Home

Regardless of which illness you have, effective symptom management can help you feel better while your body fights off the infection.

For congestion and sinus pressure, decongestants like pseudoephedrine (Sudafed) are available without a prescription but kept behind the pharmacy counter—just ask your pharmacist. Saline nasal sprays can provide relief without medication. For cough, natural options like tea with honey can be surprisingly effective, especially at night. Expectorants thin and loosen mucus in your lungs so you can cough it out more easily. Guaifenesin (Mucinex) is the most common expectorant sold over the counter.

Pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) can reduce fever and ease body aches and headaches. Stay hydrated—water, electrolyte drinks, warm tea, and broth all count.

Rest is genuinely important. Your body needs energy to fight infection, so permit yourself to actually rest. It isn't optional—it's treatment.

The challenge is that while you can manage symptoms at home, you won't know definitively which illness you have without testing. And that matters when prescription antivirals could shorten your illness or prevent complications.

When Symptoms Alone Aren't Enough

Here's the reality: you can't definitively know which illness you have without testing, and that's important for several reasons.

If you have the flu and we catch it within the first 48 hours of symptoms, antiviral medications like Tamiflu can shorten the duration of your illness and reduce severity. For high-risk patients with COVID-19—those over 65, with chronic conditions, or who are immunocompromised—early treatment with COVID-specific antivirals can prevent severe illness.

Knowing which illness you have also affects how long you need to stay home, when you can safely return to work or school, and how to protect vulnerable family members.

The Emergency Medicine Approach to Diagnosis

At RightCare Clinic, we don't just assess your symptoms—we can provide definitive answers through multi-virus rapid testing for flu A and B, COVID-19, and RSV, all available on-site.

Our board-certified Emergency Medicine physicians evaluate not just what illness you have, but how severely it's affecting you. We're assessing your oxygen levels, listening carefully to your lungs, and watching for signs of complications like dehydration or respiratory distress.

This comprehensive approach means we can provide both diagnosis and treatment planning in one visit. If testing shows you have influenza and you're within the window for antivirals, we can prescribe them immediately. If you're significantly dehydrated, we can provide IV hydration. If your symptoms suggest complications, we have on-site X-ray capabilities to check for pneumonia.

Red Flags That Always Warrant Evaluation

Regardless of which illness you suspect, certain symptoms mean you should seek professional evaluation:

• Difficulty breathing or shortness of breath
• Chest pain or pressure
• Confusion or difficulty staying awake
• Fever lasting more than 5 days, high fever that doesn’t improve with treatment
• Symptoms that improve, then suddenly worsen
• Severe dehydration (dizziness, decreased urination, extreme thirst)

These warning signs can indicate your illness is becoming more serious or that complications are developing.

Getting Answers When You Need Them

The confusion between cold, flu, and COVID isn't going away—these viruses will continue circulating together, especially during fall and winter. But you don't have to make these decisions based on guesswork.

When symptoms overlap and you need clarity, professional evaluation with appropriate testing provides answers that help us create the right treatment plan for your specific situation.

Experiencing respiratory symptoms and not sure what you're dealing with? Schedule a same-day appointment at RightCare Clinic by calling 616-888-3710 or booking online. Our board-certified emergency medicine physicians provide multi-virus testing and thorough evaluation, so you get answers and a clear treatment plan in one visit.

Todd Chassee, MD, FACEP, is Medical Director for RightCare Clinic and Vice President of Clinical Services at Emergency Care Specialists

This educational content is for informational purposes only and does not replace professional medical advice. Always consult your physician or a qualified health provider with medical questions. If you could have a medical emergency, call your doctor, 911, or go to the nearest emergency room immediately. RightCare Clinic does not endorse specific tests, physicians, products, procedures, or opinions. This content does not establish a physician-patient relationship.