When sniffles, sneezes and fatigue hit, it’s easy to wonder: is it allergies, the flu or just a cold? While these conditions can share similar symptoms, different factors cause them and different approaches to treatment require attention. Knowing the distinctions can help you recover faster — and avoid unnecessary medications or missed work.
Understanding the differences between allergies, the flu and the common cold is important. It can help you identify what your body is experiencing.
What causes each condition?
Your immune system triggers allergies by reacting to substances like pollen, dust or pet dander. Viruses do not cause them, so they are not contagious.
The flu (influenza) is a viral infection that spreads easily from person to person, especially during colder months.
A virus, most commonly rhinovirus, also causes a cold, but the cold tends to be milder than the flu.
Understanding the root cause is the first step in choosing the right remedy.
How to tell if it’s allergies, the flu or a cold
If you have itchy eyes, sneezing and a runny nose with clear mucus, you may have allergies. If these symptoms last for weeks or come back each season, it’s likely allergies. You won’t have a fever or body aches, and symptoms often improve indoors or with antihistamines.
“Allergies tend to linger and fluctuate depending on your exposure to triggers,” says Lilian McKinley, MD, a pediatrician with Mount Nittany Health. “If you notice symptoms spike after mowing the lawn or petting your cat, that’s a strong clue.”
The flu hits hard and fast. You might feel fine in the morning and be bedridden by evening. High fever, chills, body aches and extreme fatigue are hallmark signs. Unlike allergies, the flu often includes a dry cough and can lead to complications like pneumonia.
If you think you have the flu, it’s important to rest and drink plenty of fluids. If you have any chronic conditions or live with anyone with chronic conditions, contact your doctor to talk about antiviral medications within the first 48 hours. The flu is contagious, so stay home and avoid close contact with others.
A cold usually creeps in slowly. You might start with a scratchy throat, followed by nasal congestion, sneezing and a mild cough. Unlike the flu, a cold rarely causes a high fever or intense fatigue.
Most colds resolve on their own with rest, fluids and over-the-counter remedies. If symptoms worsen or linger beyond 10 days, it could be something more serious — like a sinus infection.
How to treat your symptoms and when to see a doctor
If you have mild symptoms and want to feel better at home, there are a few things you can try.
- For allergies: Use antihistamines, ask your provider about nasal sprays and avoid known triggers.
- For the flu: Rest, hydrate and ask your provider about antiviral options.
- For a cold: Focus on symptom relief — nasal saline, throat lozenges and plenty of fluids.
Avoid antibiotics unless prescribed for a bacterial complication. Neither the flu nor a cold responds to antibiotics, and bacteria do not cause allergies at all.
It’s time to consult a healthcare provider if you experience:
- Difficulty breathing
- Chest pain
- Persistent fever
- Symptoms lasting more than 10 days
These could signal complications beyond allergies, the flu or a cold.
Prevention is key when it comes to the flu
It’s important to know the difference between allergies, a cold and the flu. However, it is even better to prevent the flu completely.
“Each year, influenza leads to thousands of hospitalizations and missed days of work, school and daily activities,” says Dr. McKinley. “The flu shot is your best defense — it’s safe, fast and updated annually to match circulating strains.”
Getting vaccinated doesn’t just protect you — it helps shield your family, coworkers and vulnerable members of the community. Even if you are usually healthy, the flu can be severe. It can cause serious problems, especially for children, older adults and people with long-term health issues.
Mount Nittany Health makes it easy to stay protected. With multiple locations across the Centre region, flexible scheduling and clinics for both pediatric and adult patients — including a convenient drive-thru option — you can get your flu shot on your terms.
Flu
Discover more about Flu, including locations and providers, at Mount Nittany Health