How can I tell allergies from a cold?

Check for itching and duration. Itchy eyes, nose, or throat paired with symptoms that drag on for weeks to months signals allergies. Colds rarely itch and finish in 7 to 10 days.

Do allergies cause a fever?

No. Although the nickname is 'hay fever,' allergies never generate a fever. Body temperature that rises points to a cold, the flu, or another infection.

How long does a cold last versus allergies?

A cold runs through its course in about 7 to 10 days, peaking near day 3. Allergy symptoms can hang on for weeks or months as the allergen stays in the environment.

What color is allergy mucus?

Allergy discharge stays clear, thin, and watery. Colds shift the mucus to thicker and yellowish hues, and yellow-green drainage may mean a sinus infection has taken root.

When is it a sinus infection instead?

If you feel worse rather than better at around 10 to 14 days, with facial pain or pressure and thick yellow-green drainage, the cold could have developed into a sinus infection that deserves a doctor’s visit.

Are allergies contagious?

No. Allergies are a personal immune reaction to pollen or mold and cannot travel between people. Colds spread via respiratory droplets and contaminated surfaces.

Allergies vs. a Cold: How to Tell the Difference

Allergies and a common cold can feel like twins—both bring congestion, sneezing, and a drippy nose—yet a handful of telltale signs split them apart. The standout clue is itching: when eyes, nose, and throat itch, the culprit is almost always allergies, a symptom the American College of Allergy, Asthma & Immunology and Cleveland Clinic say a cold seldom delivers.

Duration supplies a second clue. A cold finishes its run in 7 to 10 days, cresting around day 3 before tapering off. Allergy symptoms, by contrast, can linger for weeks or even months, persisting as long as the triggering pollen or mold drifts in the air.

Allergies or a cold?

The tells that separate seasonal allergies from a common cold.

SignAllergyCold

Itchy eyes & noseYesNo

FeverNoSometimes

Body achesNoSometimes

MucusClear, thinThick, colored

OnsetSuddenGradual

Typical durationWeeks+7–10 days

Source: ACAAI, CDC, Cleveland Clinic.

Itching, fever, and mucus

Itching remains the clearest wedge. A cold hardly ever makes your eyes or throat itch, yet that sensation shows up almost every time allergies strike. Fever acts the same way—its presence signals a cold or flu, since allergies never raise body temperature despite their nickname. Mucus color and texture help, too: allergies usually produce a clear, thin, watery drip, whereas colds thicken things up and tint them yellowish. Separately these hints are modest; together they tilt the balance toward one cause.

Onset and timing

Allergies pounce within minutes of exposure and reappear around the same week each year when a particular pollen releases its grains. A cold builds more slowly, gaining steam over a day or two and peaking about day 3. Another practical split points to contagion: with a cold it is possible to pass the virus, while allergies never move from person to person.

When it is actually a sinus infection

Sometimes an ordinary cold refuses to quit and by day 10 to 14 becomes a sinus infection. Pain or pressure centered on the eyes, cheeks, or forehead and a malodorous yellow-green drain make that shift obvious. Those signals deserve a call to a doctor for evaluation rather than more watchful waiting.

What helps each one

Allergies respond best to a three-part plan—avoid the trigger, shut windows on high-pollen days, and use a second-generation antihistamine or an intranasal corticosteroid. A cold offers no quick fix: rest, fluids, and simple patience get the job done. Symptoms fade away before the 10-day mark. If you cannot tell which illness you are fighting, ask whether anything itches and how long it has lasted—those two questions nearly always solve the puzzle. Keep in mind that flu and COVID-19 can resemble a cold, yet both feature fever and body aches that allergies never produce.

A cold runs on a clock; allergies don't

7–10days

a common cold typically lasts

CDC

3days

to a cold's symptom peak

CDC

~10days

when lingering symptoms suggest sinusitis

Cleveland Clinic

Check your local pollen forecast

Pollen seasons vary sharply by region. These metros see some of the worst pollen pressure — check the current forecast for each, or look up any US city on the pollen count hub:

New York, NY pollen count — A dense metro where spring tree pollen and cold season overlap, making the two easy to confuse.
Chicago, IL pollen count — Heavy Midwest pollen seasons collide with cold-and-flu months.
Atlanta, GA pollen count — An intense, early spring tree season often mistaken for a lingering cold.
Dallas, TX pollen count — Long warm-season pollen plus winter colds blur the line year-round.
Philadelphia, PA pollen count — Overlapping tree, grass, and ragweed seasons make timing the key clue.
Denver, CO pollen count — Dry air and grass-and-weed seasons complicate telling allergies from a cold.

Frequently asked

How can I tell allergies from a cold?: Check for itching and duration. Itchy eyes, nose, or throat paired with symptoms that drag on for weeks to months signals allergies. Colds rarely itch and finish in 7 to 10 days.
Do allergies cause a fever?: No. Although the nickname is 'hay fever,' allergies never generate a fever. Body temperature that rises points to a cold, the flu, or another infection.
How long does a cold last versus allergies?: A cold runs through its course in about 7 to 10 days, peaking near day 3. Allergy symptoms can hang on for weeks or months as the allergen stays in the environment.
What color is allergy mucus?: Allergy discharge stays clear, thin, and watery. Colds shift the mucus to thicker and yellowish hues, and yellow-green drainage may mean a sinus infection has taken root.
When is it a sinus infection instead?: If you feel worse rather than better at around 10 to 14 days, with facial pain or pressure and thick yellow-green drainage, the cold could have developed into a sinus infection that deserves a doctor’s visit.
Are allergies contagious?: No. Allergies are a personal immune reaction to pollen or mold and cannot travel between people. Colds spread via respiratory droplets and contaminated surfaces.