Cold vs Flu: How to Tell the Difference and When to See a Doctor
Cold vs flu: learn how symptoms differ, how long each lasts, home care that helps, why antibiotics will not work, and when you should see a doctor.
Status: Pending Qualified Medical Review. This article has not yet been reviewed by a qualified medical professional.
Runny nose, sore throat, maybe a cough. Is it "just a cold" or is it the flu? In Bangladesh, people often call both "thanda lagse" or "jor-thanda" and treat them the same way. But flu (influenza) usually hits harder and can be dangerous for some people.
Knowing the difference helps you decide whether rest at home is enough, or whether you should speak to a doctor. This guide uses guidance from the NHS and the WHO.
The Quick Answer
The NHS sums it up like this:
| Cold | Flu | |
|---|---|---|
| How it starts | Gradually, over 1 to 3 days | Quickly, within a few hours |
| Where it hits | Mainly nose and throat | More than just nose and throat — whole body |
| How you feel | Unwell, but usually able to carry on normal activities | Exhausted, too unwell to carry on as normal |
Both are caused by viruses. Neither is helped by antibiotics.
Common Cold Symptoms
According to the NHS, cold symptoms come on gradually over 2 to 3 days. Main symptoms:
- Blocked or runny nose
- Sneezing
- Sore throat
- Hoarse voice
- Cough
- Feeling tired and unwell
You may also have:
- A high temperature
- Aching muscles
- Loss of taste and smell
- Pressure in the ears and face
Most people feel better in about 1 to 2 weeks (NHS). Symptoms can last longer in young children, who may also be irritable and have trouble feeding or sleeping.
Flu Symptoms
The NHS says flu symptoms come on very quickly and can include:
- A sudden high temperature
- An aching body
- Feeling tired or exhausted
- A dry cough
- Sore throat
- Headache
- Difficulty sleeping
- Loss of appetite
Children may also get ear pain, sore eyes, swollen glands and seem less active.
What the WHO says about flu
- Seasonal influenza is a respiratory infection caused by influenza viruses, common in all parts of the world.
- Symptoms usually begin around 2 days after infection (range 1–4 days) and usually last around a week.
- The cough can be severe and last 2 weeks or more.
- Most people recover within a week without medical care.
- But flu can cause severe illness or death, especially in high-risk groups, and can lead to pneumonia and sepsis.
Example
Sumi, 29, wakes up feeling fine. By lunchtime she has a fever of 102°F, her whole body aches, and she can barely get out of bed. That fast, heavy start points towards flu. Her husband, who has had a runny nose and mild sore throat for two days but is still going to work, more likely has a cold.
Could It Be Something Else?
In Bangladesh, a fever with body aches can also be dengue, COVID-19, chikungunya or typhoid. Clues that it may not be a simple cold or flu:
- Fever with pain behind the eyes, rash, or severe body/joint pain during mosquito season — think dengue
- Fever that slowly climbs over several days with stomach upset — typhoid is possible
- Shortness of breath
If dengue is possible, avoid ibuprofen and aspirin and use paracetamol until a doctor advises otherwise.
How to Treat a Cold or Flu at Home
For a cold (NHS)
- Rest well
- Drink lots of fluids, such as water
- Eat healthy food
- Gargle salt water for a sore throat (not suitable for children)
- Drink warm lemon and honey — the NHS suggests half a lemon in a mug of boiled water with 1 to 2 teaspoons of honey. Do not give honey to babies under 12 months.
- Breathe in steam to ease a blocked nose, for example sitting in the bathroom with a hot shower running. Do not let children breathe steam from a bowl of hot water because of the risk of burns.
- Do not smoke
For flu (NHS)
- Rest and sleep
- Paracetamol or ibuprofen to lower temperature and ease aches (but avoid ibuprofen if dengue is possible — see above)
- Drink plenty of water — your urine should be light yellow or clear
- Do not give aspirin to children under 16
- Do not take paracetamol together with flu remedies that also contain paracetamol — it is easy to take too much
Why antibiotics will not help
The NHS is clear: antibiotics do not work for viral infections such as flu. They will not relieve symptoms or speed recovery. In Bangladesh, antibiotics are often bought without a prescription for colds and flu. This adds to side effects and antibiotic resistance. A doctor may prescribe antibiotics only if a bacterial infection develops.
Who Should See a Doctor?
The NHS advises getting medical advice urgently if you have flu symptoms and:
- You are worried about a baby's or child's symptoms
- You are 65 or over
- You are pregnant or recently gave birth
- You have a long-term condition — such as diabetes, or disease of the heart, lungs, liver, kidneys, brain or nerves
- You have a weakened immune system, for example from chemotherapy or HIV
- You feel very unwell
- You feel short of breath
- Your symptoms do not improve after 7 days
The WHO also lists pregnant women, children under 5, older people and people with chronic illnesses as at higher risk of severe flu.
Emergency: Call 999 or Go to Hospital
The NHS says get emergency help if you have:
- Sudden chest pain
- Severe difficulty breathing — gasping, choking or unable to get words out
- Coughing up blood
Also seek urgent care for confusion, a child who is very drowsy or hard to wake, or bluish lips.
How to Avoid Spreading Cold and Flu
The NHS notes flu is very infectious, and you are more likely to pass it on in the first 5 days. Germs from coughs and sneezes can live on hands and surfaces for 24 hours.
- Wash hands often with soap and water
- Cover your mouth and nose with a tissue when you cough or sneeze, or use the bend of your elbow
- Throw used tissues away quickly
- Stay at home if you have a high temperature or feel too unwell for normal activities
Flu vaccine
The WHO says vaccination is the best way to prevent influenza. Ask your doctor whether a flu vaccine is suitable and available for you, especially if you are in a high-risk group.
Related reading: For children, see fever in children: when to worry. Learn why unnecessary antibiotics are risky in our article on antibiotic resistance, and if you have asthma, review how to use an inhaler.
Frequently Asked Questions
How do I know if I have a cold or flu?
Flu starts suddenly with fever, body aches and exhaustion. A cold starts gradually and mainly affects the nose and throat.
How long does flu last?
Most people recover in about a week, according to the WHO, but the cough can last 2 weeks or more.
How long does a cold last?
Usually 1 to 2 weeks, according to the NHS.
Should I take antibiotics for flu?
No. Antibiotics do not work against viruses like flu.
Can I go to work with a cold?
With a mild cold, many people can carry on. If you have a high temperature or feel too unwell, stay home to rest and avoid spreading it.
Is flu dangerous?
For most healthy people it is not, but it can be serious for older people, young children, pregnant women and people with long-term illnesses.
Feeling Unwell? Consult a Doctor on ShifaMate
If you have cold or flu symptoms and fall into a higher-risk group, or your symptoms are not improving, you can consult a verified doctor through ShifaMate. Describe your symptoms, share your temperature record, and list your medicines. At set times, "See a doctor now" sends your request straight to the on-call MBBS doctor. You can also browse ShifaMate doctors.
For chest pain, severe breathing difficulty or coughing up blood, call 999.
References
This article is for general information and does not replace advice from a qualified doctor.
Sources
This article is general health information, not medical advice for any individual. For your own situation, consult a registered doctor. In an emergency, go to the nearest hospital without delay.
