flu that comes and goes

Overview

The flu (short for influenza) is a viral infection that affects your nose, throat, and lungs. Most people feel very sick for about one to two weeks and then get better. But sometimes, flu-like symptoms seem to get better and then return, or they come and go in waves over a longer period. This can happen for several reasons, such as a weak immune system, a secondary infection, or another illness that shares symptoms with the flu.

It is fairly common for people to feel like they are getting over the flu, only to have symptoms return. This can happen when your immune system is weak, when you catch a different virus, or when a secondary infection develops.

Anyone can experience flu-like symptoms that come and go, but it is more likely if you have a weakened immune system, a chronic health condition, are pregnant, or are around many people who are sick (such as healthcare workers or teachers).

Symptoms

Common symptoms

• Fever or feeling feverish with chills
• Cough, often dry
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Feeling very tired or weak
• Chest discomfort

Symptoms in children

• Fast breathing or trouble breathing
• Bluish lips or face
• Not drinking enough fluids
• Not waking up or being very hard to wake
• Being extremely irritable or not wanting to be held

Symptoms in older adults

• Confusion or dizziness that is new
• Lack of appetite or dehydration
• Weakness that makes it hard to do daily activities
• A cough that gets worse or brings up colored mucus
• A fever that goes away and then comes back

Causes

Main causes

• Infection with the influenza virus, which can sometimes reactivate or cause lingering symptoms
• Another respiratory virus, such as a cold virus or RSV, that causes similar symptoms
• A secondary bacterial infection, such as pneumonia or a sinus infection, that develops after the flu
• An immune system that is not strong enough to clear the virus completely

Risk factors

• Being older than 65 or younger than 5
• Having a weakened immune system (due to illness or certain medicines)
• Having chronic conditions like asthma, diabetes, heart disease, or lung disease
• Being pregnant
• Smoking or being around smoke
• High stress, poor sleep, or poor nutrition

When to see a doctor

See a doctor urgently if:

• If you have emergency signs like trouble breathing or chest pain, call your local emergency number right away.
• If your flu symptoms seem to get better and then suddenly get much worse, seek care the same day.

Book a routine appointment if:

• If your symptoms have lasted longer than 10 days without clear improvement.
• If you have a fever that goes away and then comes back.
• If you have a chronic condition and you are unsure if you need treatment.

Diagnosis

A doctor will ask about your symptoms and health history, and may listen to your lungs. If your flu symptoms have come and gone, they will likely look for signs of complications or other infections. They may take a swab from your nose or throat to check for the flu virus, but this is not always needed.

Tests that may be done

• Nasal or throat swab to test for influenza or other respiratory viruses
• Chest exam and sometimes a chest X-ray if pneumonia is suspected
• Blood tests to check for infection, oxygen levels, or organ function if you are very sick
• Sputum culture (testing mucus you cough up) to look for bacterial infections

What to expect at your appointment

The doctor will explain what might be causing your symptoms and suggest next steps. This may include rest, fluids, and treating any underlying infection. If they suspect a bacterial infection, they may prescribe an antibiotic (which does not work on viruses but can treat a secondary bacterial problem). You should not expect to be given antiviral medicine unless you start it early in the flu course, but your doctor will decide based on your situation.

Treatment

Treatment for flu that seems to come and goes depends on the cause. If it is a lingering viral infection, the main care is rest, fluids, and letting your body recover. If a secondary bacterial infection is found, your doctor may prescribe antibiotics. Never take leftover antibiotics – always follow your doctor's advice.

Self-care at home

• Rest as much as you need – even if you feel better one day, your body may still be fighting the infection.
• Drink plenty of fluids like water, warm broth, and herbal tea to stay hydrated.
• Use a cool-mist humidifier or take a warm shower to ease coughing and congestion.
• Gargle with warm salt water (for adults) to soothe a sore throat.
• Avoid smoking and secondhand smoke.
• Wash your hands often to avoid giving the virus to others and to protect yourself from new infections.

Medical treatments

If the flu is diagnosed early, a doctor may prescribe an antiviral medicine that can shorten the illness and make it milder. However, this is most helpful within the first 48 hours of symptoms. If a secondary bacterial infection like pneumonia has developed, antibiotics may be needed. Some people also benefit from medicine to bring down fever or relieve pain – but always ask a pharmacist or doctor which ones are safe for you.

When is surgery considered?

This condition is not treated with surgery. If complications lead to fluid around the lungs or a lung abscess (a pocket of infection), a procedure might be needed, but that is rare and would be discussed by your specialist.

Living with this condition

Listen to your body. If you have a good day, do not overdo it – take gentle walks and keep up with rest. Keep a simple log of your symptoms, so you can notice patterns and share them with your doctor. This can help spot whether symptoms are truly coming and going or whether one symptom is simply dragging on.

Lifestyle tips

• Get enough sleep – aim for 7 to 9 hours a night.
• Manage stress with relaxing activities like deep breathing, gentle stretching, or listening to calming music.
• Slowly return to exercise, starting with short walks and adding more activity as you feel able.
• Wash hands regularly and consider wearing a mask in crowded places during flu season.
• Keep your home well-ventilated and clean surfaces that are touched often.

Diet and exercise

Eat a balanced diet with fruits, vegetables, and protein to support your immune system. If you have a fever or are coughing a lot, make sure to sip fluids throughout the day. Exercise can wait until you feel ready – start with gentle movement and stop if you feel short of breath. After a viral infection, your energy may return slowly, so be patient.

Mental health and emotional wellbeing

Feeling sick for a long time, or having symptoms that come and go, can be exhausting and worrying. It is normal to feel frustrated, anxious, or low. Talk to friends or family about how you are feeling. If sadness or anxiety lasts more than two weeks and interferes with your daily life, reach out to a mental health professional or your doctor.

Prevention

You can reduce your chances of getting the flu and of developing complications. Good hand hygiene, avoiding close contact with people who are sick, keeping your immune system strong, and getting a flu vaccine every year are the best steps.

Vaccines

A flu vaccine is recommended for everyone 6 months and older. It does not give you the flu, and it greatly lowers the risk of severe illness. Even if you have had the flu before, getting vaccinated each year helps protect you from new strains. Ask your doctor, pharmacist, or local health clinic about where to get one.

Complications

If left untreated

• Pneumonia, which is an infection in the lungs
• Bronchitis, an infection of the larger airways
• Sinus infections and ear infections
• Worsening of chronic conditions like asthma, heart failure, or diabetes
• Dehydration or worsening of overall health in older adults

Long-term outlook

Most people recover fully from the flu, even if it takes a few weeks. If symptoms seem to come and go, it often means your body is still repairing itself or that a secondary infection has developed – both can be treated. With proper rest, fluids, and medical support when needed, you can expect to feel stronger over time. Be kind to yourself and give your body the rest it needs.

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