sudden flu

Overview

The flu (influenza) is a common viral infection that attacks your nose, throat, and lungs. It often starts suddenly, which is why many people call it 'sudden flu.' For most healthy people, it is uncomfortable but not dangerous. However, it can be serious for young children, older adults, and people with certain medical conditions.

Yes, the flu is very common, especially in winter. Millions of people get it every year around the world.

Anyone can get the flu, but children, older adults, pregnant women, and people with long-term health conditions (like asthma, diabetes, or heart disease) are more likely to have serious complications.

Symptoms

Common symptoms

• Fever or feeling feverish
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headache
• Fatigue or tiredness
• Some people may have vomiting and diarrhea (more common in children than adults)

Symptoms in children

• High fever
• Fussiness or irritability
• Eating or drinking poorly
• Vomiting or diarrhea (more common in children)

Symptoms in older adults

• Fever may be lower or absent
• Confusion or dizziness
• Weakness that makes it hard to do daily activities
• Worsening of other medical conditions like heart failure or diabetes

Causes

Main causes

• Influenza viruses (types A and B)
• Spread through respiratory droplets from coughs, sneezes, or talking
• Touching surfaces with the virus and then touching your eyes, nose, or mouth

Risk factors

• Living in close quarters (like dormitories, nursing homes, military barracks)
• Being in crowded places during flu season
• Having a weakened immune system
• Age (children under 5 and adults 65 and older)
• Chronic medical conditions
• Pregnancy, especially in the second and third trimesters
• Not getting the flu vaccine

When to see a doctor

See a doctor urgently if:

• If you have trouble breathing, chest pain, confusion, or seizures — call emergency services right away
• If you have a high fever that does not come down with rest and fluids (but do not give aspirin to children or teens)
• If you are unable to keep fluids down and show signs of dehydration
• If your symptoms get better and then suddenly get worse

Book a routine appointment if:

• If you are at higher risk of complications (older than 65, pregnant, or have a chronic condition) and you think you have the flu, contact your doctor within 48 hours of symptoms starting
• If your fever lasts more than 3 days
• If you have a cough that will not go away or you feel short of breath
• If you simply want to check whether you need treatment

Diagnosis

Doctors usually diagnose the flu based on your symptoms, especially during flu season. They may also perform a swab test from your nose or throat to confirm the virus.

Tests that may be done

• A rapid influenza diagnostic test (RIDT) — a swab from your nose or throat that gives results in about 15 minutes
• A polymerase chain reaction (PCR) test — more accurate but takes longer, usually only for people at high risk or in the hospital

What to expect at your appointment

Your doctor will ask about your symptoms, when they started, and whether you have any medical conditions. They may check your temperature, listen to your lungs, and look at your throat. The visit is quick and does not hurt much.

Treatment

There is no single cure for the flu. Treatment focuses on helping your body fight the virus and managing symptoms. Most people recover at home with plenty of rest and fluids. For people at high risk, a doctor may prescribe an antiviral medicine, which can shorten the illness if taken early.

Self-care at home

• Get plenty of rest
• Drink lots of fluids like water, clear soup, or herbal tea
• Use a humidifier to ease cough and congestion
• Gargle with warm salt water for a sore throat
• Take over-the-counter pain relievers for aches and fever (always read labels and ask a pharmacist) — but never give aspirin to children or teenagers due to risk of Reye's syndrome
• Stay home from work or school until you have no fever for at least 24 hours without using fever-reducing medicine

Medical treatments

Antiviral medications may be prescribed by a doctor for people at high risk of complications, such as those with chronic conditions, older adults, or pregnant women. These are not the same as antibiotics, which do not work against viruses. They work best when started within the first 48 hours of symptoms. They are not a substitute for the flu vaccine.

Living with this condition

While you are sick, stay home and rest. Keep your distance from others. Use a separate bathroom if possible. Clean surfaces often. Drink fluids frequently. Use tissues and dispose of them properly. Wash your hands often.

Lifestyle tips

• Get enough sleep
• Stay hydrated
• Avoid smoking and alcohol
• Keep stress low as you recover

Diet and exercise

Eat light, easy-to-digest foods like soup, toast, and applesauce. You may lose your appetite — that's normal. Don't push yourself to exercise until you feel better. Gentle movement, like walking inside your home, is fine if you have energy.

Mental health and emotional wellbeing

Feeling sick and isolated can affect your mood. It is normal to feel frustrated, anxious, or down. Talk to friends or family by phone or video call. If you feel hopeless or like you cannot cope, reach out to a mental health professional or a crisis line.

Prevention

You can lower your risk of getting the flu. The best way is to get a flu vaccine every year. Good hygiene and staying away from sick people also help.

Vaccines

The flu vaccine is recommended for everyone aged 6 months and older, unless a doctor tells you otherwise. It is especially important for people at high risk. The vaccine cannot give you the flu because it does not contain a live virus. It takes about two weeks to become protective.

Screening programmes

There is no routine screening test for the flu. If you have symptoms, your doctor may test you for the virus, but this is not the same as screening.

Complications

If left untreated

• Pneumonia (a lung infection)
• Bronchitis (inflammation of the airways)
• Sinusitis or ear infections
• Worsening of chronic conditions like asthma, heart failure, or diabetes
• In severe cases, multi-organ failure or sepsis (a life-threatening whole-body reaction)

Long-term outlook

Most people recover from the flu within one to two weeks without long-term problems. Some may feel tired for a while longer. For people at high risk, the flu can be serious, but with early medical care and good home support, most make a full recovery. The flu vaccine remains the best protection.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.