You usually notice it as you pour your morning coffee. The guy in the next cubicle or office doesn't sound so good. He's coughing and sniffling as he types away, hoping you won't notice. You ask him if he's doing okay, even though you know what he's going to say.

"I'm great. It's just allergies," he says with a hoarse voice in between coughing fits. But you already know: He probably has a cold. Or even the flu.

Those "allergies" turn out to be something else and, before you know it, you're burning four sick days (or worse, vacation days).

I asked Dr. Natalie Dryden, primary care physician at Houston Methodist, for advice on how to distinguish between a cold or flu and allergies — and when you really need to see a doctor.

"Distinguishing between allergies and a cold or flu isn't always easy," says Dr. Dryden. "While colds and the flu are infectious illnesses caused by viruses. and allergies are an immune response to some environmental trigger, the body often has overlapping and similar responses, so symptoms can be similar as well."

5 signs that can help you decide if it's a cold or flu

1. Fever. The flu generally causes high fever fairly consistently, while viral colds don't often cause fever. And if they do, it's generally a low-grade fever. Allergies should never cause fever.

2. Body aches. Aches and pains tend to be very pronounced with the flu — and while they can occur with a common cold, they're typically mild. Body aches are not common with allergies.

3. Cough. A flu cough tends to be more severe than the type of cough that accompanies a cold. Like a fever and body aches, a cough is much less common with allergies.

4. Runny nose. Nasal drainage can occur during a cold or flu, as well as with allergies.

5. Sore throat. Throat irritation and pain is common with colds and flu. Typically, people with allergies report having an itchy throat and not actual pain.

The time of year can also help you decide

Keeping an eye on the seasons may clue you in on what may be going on.

While all three conditions can occur year-round, flu season typically occurs fall through spring in the U.S. If you're wondering if it's cold or flu season, check our flu tracker to see the current number of cold and flu cases.

Common colds occur most often in the winter, while allergies tend to occur with changes in the season, depending on what an individual is allergic to. Some people (like me, sadly) have allergies year-round.

Allergy symptoms tend to last as long as a person is exposed to an allergen or trigger, while viral infections will usually last between a few days to two weeks.

When in doubt, stay home

The next time you feel an itchy throat and dull body aches coming on with a fever, consider what might be ailing you before you go to work and risk getting your coworkers sick. Visit a doctor right away (you can even see a doctor online now). Your office mates will appreciate it and you'll be back on your feet faster.

And it's always a good idea to practice behaviors that help protect yourself from the flu, as well as to make sure to get your annual flu shot and wash your hands regularly, especially during flu season.

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