You woke up with a scratchy throat and a blocked nose. Whether that is a cold, influenza or an allergic reaction changes what you should do about it — and how long you should expect it to last.
Here is how our GPs tell them apart.
Speed of onset is the biggest clue
A cold builds gradually over a day or two, starting with a sore or scratchy throat and moving to congestion.
Influenza arrives abruptly. People often recall the hour it started. Fever, body aches and profound exhaustion come together and hit hard.
Allergies begin when you meet the trigger — dust, a change of season, a particular building — and stop when you leave it. They can persist for weeks without ever producing a fever.
The distinguishing symptoms
Some symptoms point strongly in one direction.
- Fever and body aches — flu, occasionally a cold, essentially never allergies
- Itchy eyes, nose or throat — allergies, rarely anything else
- Gradual sore throat then congestion — a cold
- Sudden exhaustion where getting out of bed is difficult — flu
- Symptoms that vanish in a different environment — allergies
Dubai-specific triggers
Air conditioning dries the airways and circulates dust, and the shift between outdoor heat and indoor cold is itself irritating. Sandy and dusty conditions drive a great deal of the allergic symptoms seen here, and construction dust adds to it in some neighbourhoods.
Many people who assume they have back-to-back colds through the winter actually have persistent allergic rhinitis.
When to be seen
Most colds resolve on their own in a week or so and do not need antibiotics — they are viral, and antibiotics do nothing to them.
- Difficulty breathing or chest pain — be seen urgently
- Fever above 39°C, or a fever lasting more than three days
- Symptoms improving then suddenly worsening
- A cough persisting beyond three weeks
- Any illness in someone frail, pregnant or immunosuppressed
Common questions
How do I tell flu from a cold?
Onset is the clearest difference. A cold builds gradually over a day or two; influenza arrives abruptly with fever, body aches and exhaustion severe enough that people remember when it started.
Can allergies cause a fever?
No. Allergic reactions do not cause fever. A fever points at an infection, which is one of the more useful distinctions available without a test.
Do I need antibiotics for a cold?
No. Colds are viral and antibiotics have no effect on them. They are appropriate only where a bacterial infection is suspected, which a doctor assesses.
This article is general health information, not medical advice, and does not replace a consultation. Care at Smart Care Polyclinic is provided by DHA-licensed clinicians.