Flu-Like Symptoms: Cold, Flu, COVID or Something Else?

Flu-like symptoms can make you feel suddenly unwell, tired, achy, feverish and unable to carry on as normal. You may have a cough, sore throat, runny nose, headache, chills, body aches, loss of appetite, nausea or diarrhoea. The difficult part is that several common illnesses can feel similar, including flu, COVID-19, a common cold, RSV, tonsillitis, chest infection, norovirus and other viral infections.

Most flu-like illnesses improve with rest, fluids and symptom relief. But some people are at higher risk of complications, and some symptoms need urgent medical advice. It is especially important to seek help if you have shortness of breath, chest pain, confusion, severe weakness, dehydration, a non-blanching rash, or symptoms that are rapidly worsening.

This guide explains common causes of flu-like symptoms, how cold, flu and COVID can overlap, what may help at home, when to speak to a pharmacist or GP, and when to call 999.

Quick answer: Flu symptoms usually come on quickly and often cause sudden fever, aching, exhaustion, dry cough, sore throat and headache. Colds usually develop more gradually and mainly affect the nose and throat. COVID-19 can look like either, so testing may be needed if you need to know. Seek urgent help for breathing difficulty, chest pain, confusion, collapse, severe dehydration or rapidly worsening symptoms.

What are flu-like symptoms?

Flu-like symptoms usually mean a group of symptoms that affect the whole body, not just one area. You may feel suddenly ill, weak, feverish, shivery or achy.

Common flu-like symptoms include:

high temperature or feeling feverish
chills or shivering
aching muscles or body aches
tiredness or exhaustion
headache
dry cough
sore throat
runny or blocked nose
loss of appetite
difficulty sleeping
nausea or vomiting
diarrhoea or tummy pain
feeling generally unwell

The NHS says flu symptoms come on very quickly and can include a sudden high temperature, aching body, tiredness or exhaustion, dry cough, sore throat, headache, difficulty sleeping, loss of appetite, and sometimes diarrhoea, tummy pain, nausea or vomiting. See NHS guidance on flu.

Cold, flu and COVID: why they are hard to tell apart

Cold, flu and COVID can all cause respiratory symptoms such as cough, sore throat, runny nose, headache and tiredness. They can also spread from person to person through droplets, close contact and contaminated hands or surfaces.

It is often not possible to know for certain which illness you have based on symptoms alone. This is especially true when symptoms are mild or when several viruses are circulating at the same time.

As a general guide:

Cold: often develops gradually and mainly affects the nose and throat.
Flu: often comes on suddenly and makes you feel much more exhausted and achy.
COVID-19: can range from mild cold-like symptoms to more serious illness, and symptoms can overlap with flu or a cold.

UKHSA explains that flu is usually far worse than an ordinary cold, and that cold symptoms usually occur gradually, while flu symptoms develop rapidly and extreme tiredness is common. See UKHSA guidance on flu, COVID-19 and cold symptoms.

Common cold symptoms

A common cold is usually milder than flu. Symptoms often build gradually over a day or two and mainly affect the upper airways.

Common cold symptoms include:

runny nose
blocked nose
sneezing
sore throat
cough
mild headache
mild tiredness
feeling generally under the weather

A cold can still make you feel miserable, but it is less likely than flu to cause sudden exhaustion, severe body aches or a high fever. Most colds improve within 1 to 2 weeks, although a cough can last longer.

NHS guidance advises seeing a GP if cold symptoms do not get better after 10 days, if a cough lasts more than 3 weeks, if symptoms get worse, if you have a high temperature for more than 3 days, or if you feel short of breath or have chest pain. See NHS advice on the common cold.

Flu symptoms

Flu usually feels more intense than a cold. It often starts suddenly and can make you feel too unwell to work, study, exercise or do normal daily tasks.

Flu symptoms may include:

sudden high temperature
aching body
feeling tired or exhausted
dry cough
sore throat
headache
chills
loss of appetite
difficulty sleeping
sometimes diarrhoea, tummy pain, nausea or vomiting

Flu can be serious for some people, including older adults, pregnant women, people with long-term conditions and people with weakened immune systems. If you are in a higher-risk group and develop flu-like symptoms, seek advice earlier.

COVID-19 symptoms

COVID-19 symptoms can vary. Some people have mild cold-like symptoms, while others develop fever, cough, fatigue, breathlessness or more significant illness. Some people also develop changes in taste or smell, although this is not present in everyone.

Possible COVID-19 symptoms include:

high temperature or shivering
new or worsening cough
shortness of breath
tiredness or exhaustion
body aches
headache
sore throat
blocked or runny nose
loss or change to sense of smell or taste
loss of appetite
diarrhoea
nausea or vomiting

NHS guidance says it is not always possible to treat COVID-19, but rest, fluids and symptom relief can help with symptoms such as high temperature, cough and breathlessness. See NHS guidance on COVID-19 symptoms and what to do.

Can you tell flu and COVID apart without a test?

Not reliably. Flu, COVID and other respiratory viruses can overlap. A sudden severe illness with high fever and body aches may sound like flu, but COVID can also cause fever, aches and tiredness. A runny nose and sore throat may sound like a cold, but COVID can also start that way.

Testing may be useful if:

you are at higher risk of severe illness
you live or work with vulnerable people
you work in healthcare or social care
you are visiting a care home, hospital or vulnerable person
your employer or setting has specific guidance
you need to know whether to access antiviral treatment or specialist advice

Even without testing, it is sensible to reduce contact with others when you have fever, feel very unwell, or have symptoms that could spread to vulnerable people.

Other illnesses that can feel like flu

Not every flu-like illness is flu, COVID or a cold. Several other conditions can cause fever, aches, fatigue and feeling generally unwell.

Other possibilities include:

RSV or other respiratory viruses
tonsillitis
sinusitis
chest infection or pneumonia
urinary tract infection
kidney infection
food poisoning or norovirus
glandular fever
meningitis or sepsis, which are emergencies
inflammatory conditions
medicine reactions

The symptoms around the flu-like illness are important. For example, burning when urinating may suggest a urine infection. Severe sore throat and swollen glands may suggest tonsillitis or glandular fever. Vomiting and diarrhoea may suggest food poisoning or norovirus.

Flu-like symptoms with sore throat

A sore throat is common with colds, flu, COVID and tonsillitis. Most sore throats improve by themselves, but some need medical advice.

Consider tonsillitis or throat infection if you have:

very sore throat
pain when swallowing
swollen glands
fever
white spots or pus on the tonsils
bad breath
no cough with fever and swollen tonsils

Seek urgent advice if you cannot swallow fluids, have difficulty breathing, drooling, severe one-sided throat pain, neck swelling, or symptoms are rapidly worsening.

Flu-like symptoms with cough

Cough is common with cold, flu and COVID. It can also happen with bronchitis, asthma flare, chest infection, pneumonia, reflux or smoking-related irritation.

Seek medical advice if a cough:

lasts more than 3 weeks
is getting worse
comes with shortness of breath
comes with chest pain
comes with coughing up blood
comes with high or persistent fever
comes with confusion or severe weakness
happens in someone with a long-term lung, heart or immune condition

See Cough in Adults: Causes, Red Flags and When to See a GP and Shortness of Breath: Common Causes and When to Call 999.

Flu-like symptoms with fever and chills

Fever and chills are common with flu and many infections. Chills happen when your body is trying to raise its temperature, and sweating can happen when the fever starts to break.

Get medical advice if fever:

lasts more than 3 days
is very high
keeps coming back
comes with severe headache, stiff neck or rash
comes with confusion or drowsiness
comes with shortness of breath or chest pain
comes with severe abdominal pain
comes with signs of dehydration
affects someone at higher risk of complications

Flu-like symptoms with nausea, vomiting or diarrhoea

Flu can sometimes cause tummy symptoms, although vomiting and diarrhoea are less common in adults than respiratory symptoms. If vomiting and diarrhoea are the main symptoms, food poisoning, norovirus or another stomach bug may be more likely.

Watch for dehydration if you have vomiting or diarrhoea. Signs may include dark urine, peeing less often, dry mouth, dizziness, weakness, headache or confusion.

Seek advice if you cannot keep fluids down, have blood in stool, severe abdominal pain, persistent vomiting, high fever, symptoms after travel, or you are pregnant, older, frail, immunosuppressed or have a significant long-term condition.

Useful guides include Nausea: Common Causes, What Helps and When to Get Medical Advice, Food Poisoning: Symptoms, How Long It Lasts and When to Get Help, What Is Norovirus? and Dehydration Symptoms in Adults and Children.

Flu-like symptoms with rash or itchy skin

A rash can happen with some viral infections, allergic reactions, heat rash, medicine reactions or more serious infections. Itchy skin can also happen during illness, after medicines, with hives, or because fever and sweating irritate the skin.

Seek urgent help if a rash:

does not fade when pressed with a glass
comes with fever and severe illness
comes with stiff neck or light sensitivity
comes with breathing difficulty
comes with swelling of lips, tongue, throat or face
is blistering, painful or spreading quickly
is linked with confusion, drowsiness or collapse

Flu-like symptoms with headache

Headache is common with flu, COVID, colds, fever, dehydration, sinusitis and migraine. Usually it improves as the illness settles.

Seek urgent help if headache is:

sudden and severe
the worst headache you have ever had
linked with confusion, weakness, seizure or fainting
linked with stiff neck, fever or rash
linked with new vision loss
after a head injury
getting worse despite treatment

For more detail, see Headache: Causes, Red Flags and When to Seek Urgent Help, Migraine: Symptoms, Triggers and Treatment Options in the UK and Sinusitis: Symptoms, Causes and Treatment.

Flu-like symptoms with chest pain or breathlessness

Flu-like symptoms with chest pain or breathlessness need more caution. They can happen with flu, COVID, chest infection, pneumonia, asthma flare, heart problems, blood clot or other serious causes.

Call 999 if you have:

severe shortness of breath
difficulty speaking because of breathlessness
chest pain, pressure, heaviness or tightness
pain spreading to the arm, back, neck or jaw
blue, grey or pale lips, tongue or skin
confusion or severe drowsiness
collapse or fainting
symptoms that are rapidly worsening

See Chest Pain: When to Worry and When It’s Not Your Heart and Shortness of Breath: Common Causes and When to Call 999.

Flu-like symptoms after travel

Flu-like symptoms after travel may be caused by common respiratory viruses, food poisoning or travel-related infections. The destination, timing, mosquito exposure, animal contact, food and water exposure, and vaccination history all matter.

Seek medical advice if you develop fever after recent travel, especially if you visited a country where malaria, dengue or other serious infections are possible.

Tell the clinician:

where you travelled
when you returned
whether you had mosquito bites
whether you took malaria prevention tablets
whether you had diarrhoea or vomiting
whether you had animal contact
whether anyone else is unwell

Do not assume flu-like symptoms after travel are “just a virus” if you have fever, rash, severe headache, confusion, jaundice, shortness of breath or severe abdominal symptoms.

Who is at higher risk from flu-like illnesses?

Some people are more likely to become seriously unwell from flu, COVID and other infections. They should seek advice earlier if symptoms are worsening or concerning.

Higher-risk groups include:

older adults
pregnant women
babies and very young children
people with asthma, COPD or other lung disease
people with heart disease
people with diabetes
people with kidney disease
people with liver disease
people with neurological conditions
people with weakened immune systems
people receiving chemotherapy or immunosuppressive medicines
people living in care homes or other residential settings

If you have a long-term condition and become more unwell than expected, seek advice from your GP, NHS 111, specialist team or urgent care depending on the severity.

What helps flu-like symptoms at home?

Most mild flu-like illnesses can be managed at home. The aim is to rest, avoid dehydration, ease symptoms and reduce the risk of spreading infection.

What may help:

rest as much as possible
drink fluids regularly
eat small amounts if you feel able
use paracetamol or ibuprofen if suitable for you
use honey in warm drinks for cough if appropriate, but not for children under 1 year
use saline spray or steam-free nasal care for blocked nose
avoid alcohol
avoid smoking or smoky environments
keep the room comfortably ventilated
seek pharmacy advice for symptom relief

Do not take more than the recommended dose of medicines. Be careful with combination cold and flu remedies because they may contain paracetamol as well as other ingredients.

Should you go to work, school or visit others?

If you have flu-like symptoms and feel unwell, it is best to stay home where possible, especially if you have a fever or feel too ill for normal activities. This helps you recover and reduces the chance of spreading infection to others.

Avoid close contact with people at higher risk, such as older adults, pregnant women, newborn babies, people with weakened immune systems and people with serious long-term conditions.

UKHSA advice says children and young people who are unwell and have a high temperature should stay at home and avoid contact with other people where they can. Children with a minor cough or common cold may be able to attend school if they are otherwise well. See UKHSA guidance on avoiding flu, COVID-19 and other respiratory illnesses.

How to reduce spreading flu-like illness

Respiratory viruses spread easily, especially indoors. Simple steps can reduce the risk to others.

Helpful steps include:

stay home if you have fever or feel very unwell
avoid close contact with vulnerable people while infectious
wash hands regularly with soap and water
use tissues for coughs and sneezes
throw used tissues away promptly
clean frequently touched surfaces
keep indoor spaces ventilated where possible
consider wearing a face covering if you must be around vulnerable people
follow workplace, school, healthcare or care home guidance

When to see a pharmacist

A pharmacist can help with many mild flu-like symptoms, especially if you need advice on cough remedies, sore throat relief, nasal congestion, fever medicines, hydration, or whether a symptom needs GP review.

Ask a pharmacist if:

you are unsure which cold or flu medicine is suitable
you take regular medicines
you have high blood pressure, asthma, diabetes or heart disease
you are pregnant or breastfeeding
you are buying medicine for a child
you are worried about medicine interactions
symptoms are mild but uncomfortable

For more about pharmacy advice, see When to See a Pharmacist Instead of a GP.

When to contact a GP or NHS 111

Contact a GP, out-of-hours service or NHS 111 if:

symptoms are getting worse rather than better
you have a high temperature for more than 3 days
you feel hot, cold or shivery and very unwell
you have a cough lasting more than 3 weeks
you are short of breath but it is not immediately life-threatening
you have chest pain that concerns you
you have signs of dehydration
you are vomiting repeatedly
you have severe sore throat or difficulty swallowing fluids
you have ear pain, sinus pain or symptoms that are not improving
you have a long-term condition such as diabetes, heart, lung, kidney or immune disease
you are pregnant
you are older, frail or immunosuppressed
you recently travelled and have fever
you are unsure what to do

You can use NHS 111 online in England if you need urgent advice and it is not a 999 emergency.

If you need help arranging care, see How to Get a GP Appointment Quickly in the UK.

When to call 999

Call 999 if flu-like symptoms come with signs of a medical emergency.

Call 999 if you or someone else has:

severe difficulty breathing
blue, grey, pale or blotchy lips, skin or tongue
chest pain, pressure or heaviness
collapse or fainting
confusion or severe drowsiness
seizure
signs of stroke such as face drooping, arm weakness or speech problems
a rash that does not fade when pressed
stiff neck with fever or severe headache
severe dehydration
rapidly worsening symptoms
symptoms of sepsis

Trust your judgement. If someone looks seriously unwell or is deteriorating quickly, seek urgent help.

What tests might be needed?

Most mild flu-like illnesses do not need tests. A clinician may consider tests if symptoms are severe, persistent, unusual, or if you are at higher risk.

Possible tests include:

COVID test
flu or respiratory virus test in selected situations
temperature, pulse, oxygen level and blood pressure
chest examination
urine test if urinary infection is possible
blood tests if infection or inflammation is suspected
chest X-ray if pneumonia or serious chest infection is possible
stool test if diarrhoea is severe, bloody, prolonged or travel-related

Can vaccines help prevent flu-like illness?

Vaccines can reduce the risk of severe illness from flu, COVID-19 and some other infections. Eligibility changes over time, so check current NHS guidance if you are older, pregnant, have a long-term condition, are immunosuppressed, work in health or social care, or care for someone vulnerable.

Flu and COVID vaccines do not prevent every respiratory infection, and they may not stop all symptoms, but they can reduce the chance of serious illness in higher-risk groups.

Frequently asked questions about flu-like symptoms

How can I tell if it is flu or a cold?

Flu usually comes on quickly and causes sudden fever, body aches and exhaustion. A cold usually develops more gradually and mainly causes runny nose, blocked nose, sneezing, sore throat and mild cough. However, symptoms overlap, and it is not always possible to tell for certain.

How can I tell if it is flu or COVID?

You often cannot tell reliably from symptoms alone. Both can cause fever, cough, sore throat, headache, body aches and tiredness. A COVID test may be useful if you need to know, especially if you are at higher risk or have contact with vulnerable people.

Can flu cause vomiting or diarrhoea?

Yes, flu can sometimes cause tummy pain, nausea, vomiting or diarrhoea, although these are less common in adults. If vomiting and diarrhoea are the main symptoms, a stomach bug, norovirus or food poisoning may be more likely.

How long do flu-like symptoms last?

Many viral illnesses improve within a few days to a week, but tiredness and cough can last longer. Seek medical advice if symptoms are worsening, fever lasts more than 3 days, cough lasts more than 3 weeks, or you are high risk or very unwell.

Should I stay off work with flu-like symptoms?

If you have fever, feel very unwell, or are likely to spread infection, it is sensible to stay home where possible. Avoid close contact with vulnerable people until you are improving and no longer feverish.

When should I call NHS 111?

Use NHS 111 if symptoms are worsening, you are short of breath but not in immediate danger, you have signs of dehydration, fever is persistent, you have a long-term condition, you are pregnant, or you are unsure what to do.

When should I call 999?

Call 999 for severe breathing difficulty, chest pain or pressure, blue or grey lips, confusion, collapse, seizure, stroke symptoms, a rash that does not fade when pressed, severe dehydration or rapidly worsening illness.

Can allergies feel like flu?

Allergies can cause sneezing, runny nose, itchy eyes and cough, but they usually do not cause fever, severe body aches or sudden exhaustion. If itching, rash or hay fever symptoms are prominent, allergy may be part of the picture.

Can flu-like symptoms be sepsis?

Rarely, serious infections and sepsis can start with flu-like symptoms. Seek urgent help if someone is very unwell, confused, breathing fast, has mottled or blue skin, a non-blanching rash, severe pain, reduced urination, collapse or rapidly worsening symptoms.

Do antibiotics help flu-like symptoms?

Antibiotics do not treat viruses such as cold, flu or COVID. They may be needed if a bacterial infection is suspected, such as some cases of pneumonia, tonsillitis, urinary infection or skin infection. A clinician will decide based on symptoms and examination.

What can I take for flu-like symptoms?

Rest, fluids and suitable pain relief such as paracetamol or ibuprofen may help, if you can take them safely. Ask a pharmacist before using cold and flu remedies if you take other medicines, have high blood pressure, are pregnant, or have a long-term condition.

Can I have flu-like symptoms without a fever?

Yes. Some viral illnesses cause aches, tiredness, sore throat or cough without a high temperature. Older adults, immunosuppressed people and some people taking medicines may also have infection without a typical fever.

Final thoughts

Flu-like symptoms can be caused by flu, COVID, a cold, RSV, tonsillitis, chest infection, stomach bugs and many other illnesses. The pattern matters: sudden exhaustion and body aches suggest flu, gradual runny nose and sneezing suggest a cold, but COVID can overlap with both.

Most mild cases improve with rest, fluids, symptom relief and avoiding close contact with vulnerable people. Seek medical advice if symptoms are worsening, fever persists, you are short of breath, you have chest pain, you are dehydrated, you are pregnant, older, immunosuppressed or have a long-term condition. Call 999 for severe breathing difficulty, chest pain, confusion, collapse, blue lips, stroke symptoms or a non-blanching rash.

For official guidance, see NHS information on flu, the common cold, COVID-19 symptoms and what to do, and NHS 111 online for urgent symptom advice.

This article is for general information only and should not replace medical advice. If you are worried about flu-like symptoms or someone looks seriously unwell, contact NHS 111, your GP, a pharmacist, or call 999 in an emergency.