You wake up with a stuffy nose, scratchy throat, and that familiar foggy feeling. Is it allergies acting up again—or are you actually getting sick? In Brooklyn and Queens, where spring pollen season overlaps with lingering flu and COVID circulation, this question isn’t always easy to answer.
Getting it wrong matters. Treating allergies with rest and fluids won’t stop the sneezing. Taking antihistamines for the flu won’t prevent you from spreading it to your family. And mistaking COVID for allergies could mean days of unknowingly exposing others.
At AG Care, we help patients sort out these symptoms every day. Here’s how to tell the difference—and when to come in for testing.
Why It’s So Hard to Tell the Difference
Allergies, colds, flu, and COVID all affect your respiratory system. They share common symptoms like congestion, coughing, and fatigue. But they have fundamentally different causes—and that means different treatments.
- Allergies are an immune overreaction to harmless substances like pollen, dust, or pet dander. They’re not contagious.
- Colds are caused by viruses (usually rhinoviruses). They’re contagious but typically mild.
- Influenza (flu) is caused by influenza viruses. It’s highly contagious and can be severe, especially for vulnerable populations.
- COVID-19 is caused by the SARS-CoV-2 virus. Symptoms vary widely, from mild to severe, and it remains contagious.
The key to telling them apart lies in the specific symptom patterns, how quickly they develop, and how long they last.
The Complete Symptom Comparison
Use this chart to help identify what you’re dealing with. Remember: when in doubt, get tested—especially if you have fever, severe symptoms, or known exposure to flu or COVID.
| Symptom | Allergies | Cold | Flu | COVID-19 |
|---|---|---|---|---|
| Onset | Immediate after exposure | Gradual (1-3 days) | Sudden (hours) | Gradual (2-14 days) |
| Duration | Weeks to months | 7-10 days | 1-2 weeks | Variable (days to weeks) |
| Fever | Never | Rare/low-grade | Common, often high (100-104°F) | Common |
| Body aches | Never | Mild | Severe, widespread | Common |
| Chills | Never | Rare | Common | Common |
| Fatigue | Mild to moderate | Mild | Severe, can last weeks | Common, sometimes prolonged |
| Headache | Sinus pressure type | Sometimes | Common, often severe | Common |
| Itchy eyes/nose/throat | Very common (key sign) | Rare | Rare | Rare |
| Sneezing | Common, often in bursts | Common | Sometimes | Sometimes |
| Nasal congestion | Common, clear discharge | Common, may turn thick/colored | Sometimes | Sometimes |
| Sore throat | Scratchy/itchy (from postnasal drip) | Common | Sometimes | Common |
| Cough | Dry, from postnasal drip | Mild to moderate | Common, can be severe | Common, often dry |
| Shortness of breath | Only if asthma triggered | Rare | Sometimes (if severe) | Can occur (warning sign) |
| Loss of taste/smell | Reduced (from congestion) | Reduced (from congestion) | Rare | Common (often sudden) |
| Contagious? | No | Yes | Yes, highly | Yes |
Key Questions to Ask Yourself
When you’re trying to figure out what’s making you miserable, these questions can help narrow it down:
1. Do you have a fever?
This is the single most important differentiator. Allergies never cause fever. If you have a temperature of 100°F or higher, you’re dealing with an infection—not allergies. The flu typically brings high fevers (100-104°F), while colds may cause low-grade fever or none at all. COVID fever varies but is common.
2. Are your eyes, nose, or throat itchy?
Itchiness is the hallmark of allergies. If your eyes are watery and itchy, your nose tickles, or your throat has that irritating scratchy feeling—that’s your immune system reacting to an allergen. Infections rarely cause itchiness.
3. How quickly did symptoms appear?
- Allergies: Symptoms appear within minutes to hours of allergen exposure
- Cold: Symptoms develop gradually over 1-3 days
- Flu: Symptoms hit suddenly—you might feel fine in the morning and terrible by afternoon
- COVID: Symptoms typically develop 2-14 days after exposure
4. Do you have body aches?
Significant muscle aches and joint pain point toward infection, especially the flu. The flu is notorious for causing severe, whole-body aches that make you feel like you’ve been hit by a truck. Allergies don’t cause body aches.
5. Is there a pattern to your symptoms?
Allergies follow patterns. Symptoms may be worse in the morning, after being outdoors, or during specific seasons. If your symptoms improve when you’re indoors with air conditioning or after rain (which clears pollen), allergies are likely. If symptoms are constant regardless of environment or time of day, infection is more likely.
6. Have you been exposed to someone sick?
If family members, coworkers, or classmates have been sick with similar symptoms, you’re probably dealing with an infection. Allergies aren’t contagious—you can’t “catch” them from someone else.
When Allergies and Infections Overlap
Here’s what makes diagnosis tricky: you can have allergies AND an infection at the same time. In fact, research from the American Academy of Allergy, Asthma & Immunology shows that people with allergies are more susceptible to sinus infections because chronic inflammation and congestion create an ideal environment for bacteria.
Signs you may have both:
- Allergy symptoms that suddenly get worse
- New symptoms like fever, facial pain, or thick discolored mucus
- Symptoms that persist beyond your typical allergy duration
- Allergy medications that suddenly stop working
If you suspect your allergies have progressed to a sinus infection, it’s time to see a provider who can evaluate you and determine if you need antibiotics or other treatment.
Special Considerations for 2026
As of March 2026, here’s the current respiratory illness landscape in New York:
- Flu: The CDC reports that Influenza B has been circulating heavily this season and remains active in the Northeast. If you have sudden onset of high fever, severe body aches, and exhaustion—get a flu test. Antiviral medications like Tamiflu work best when started within 48 hours.
- COVID-19: COVID continues to circulate year-round. While many cases are now milder due to immunity and updated vaccines, testing remains important—especially if you’re around vulnerable individuals or have severe symptoms.
- Allergies: Tree pollen season is underway in Brooklyn and Queens. Oak, birch, and maple are releasing pollen now, with counts expected to peak in April and May.
The “Antihistamine Test”
Here’s a practical trick: try taking an over-the-counter antihistamine (like cetirizine, loratadine, or fexofenadine). If your symptoms improve significantly within a few hours, allergies are likely the culprit. If antihistamines have little to no effect, you’re probably dealing with an infection.
Important: This test helps distinguish allergies from infections but doesn’t tell you which infection you have. If you have fever, severe symptoms, or known exposure to flu or COVID, get tested regardless of antihistamine response.
When to Get Tested at AG Care
Don’t guess when testing can give you answers. Visit AG Care for testing if you have:
- Fever of 100°F or higher
- Sudden onset of severe symptoms (especially body aches, chills, extreme fatigue)
- Known exposure to someone with confirmed flu or COVID
- Shortness of breath or difficulty breathing
- Symptoms that worsen after initially improving
- High-risk factors (age 65+, pregnancy, chronic conditions, weakened immune system)
- Uncertainty—when you just can’t tell what you have
We offer rapid flu and COVID testing with results often available during your visit. If it’s the flu, we can prescribe antiviral medications. If it’s allergies, we can recommend effective treatments and discuss whether allergy testing might help you get ahead of future seasons.
Treatment Approaches by Condition
Once you know what you’re dealing with, treatment becomes clearer:
For Allergies:
- Antihistamines (cetirizine, loratadine, fexofenadine)
- Nasal corticosteroid sprays (fluticasone, mometasone)
- Decongestants (short-term use only)
- Allergen avoidance strategies
- Allergy testing to identify specific triggers
- Immunotherapy (allergy shots) for long-term relief
For Colds:
- Rest and hydration
- Over-the-counter symptom relief (pain relievers, decongestants, cough suppressants)
- Salt water gargles for sore throat
- Time—most colds resolve in 7-10 days
For Flu:
- Antiviral medications (Tamiflu, Xofluza) if started within 48 hours
- Rest and hydration
- Fever and pain management
- Monitoring for complications
- Prevention: annual flu vaccination
For COVID-19:
- Antiviral treatments (Paxlovid) for eligible patients
- Rest and hydration
- Isolation to prevent spread
- Monitoring for worsening symptoms
- Prevention: staying current on COVID vaccinations
Protecting Yourself and Others
Whatever you’re dealing with, these practices help:
- Stay home when sick with fever or acute symptoms (infections are most contagious in the first few days)
- Wash hands frequently with soap and water for at least 20 seconds
- Cover coughs and sneezes with your elbow or a tissue
- Keep up with vaccinations—flu shots and COVID boosters are available at all AG Care locations
- Manage allergies proactively so you can recognize when something different is going on
The Bottom Line
Figuring out whether you have allergies, a cold, the flu, or COVID can feel overwhelming—but paying attention to the details helps. No fever + itchiness + predictable patterns = probably allergies. Fever + body aches + sudden onset = likely an infection that warrants testing.
When you’re unsure, don’t guess. AG Care offers walk-in testing and treatment at five convenient locations throughout Brooklyn and Queens: Bushwick, Brownsville, Flatbush Junction, Canarsie, and Jamaica, Queens.
Walk-ins are welcome, or check in online to save time. We accept most insurance plans and offer affordable self-pay options.
Questions? Call us at 877.471.9091 or visit your nearest AG Care location today.
This article is part of our Allergies & Respiratory Health Series for Brooklyn and Queens residents:
- Part 1: Spring Allergies in Brooklyn & Queens: Symptoms, Treatment & Testing
- Part 2: Allergies vs. Cold vs. Flu vs. COVID: How to Tell the Difference (You’re reading it)
- Part 3: Asthma & Allergies: When Pollen Triggers Breathing Problems (Coming Soon)
- Part 4: Sinus Health: Preventing and Treating Sinus Infections (Coming Soon)
- Part 5: Allergy Testing & Long-Term Relief: Beyond Antihistamines (Coming Soon)