Mon | Jan 25, 2021

Dear Doc | The common flu versus dengue

Published:Sunday | December 1, 2019 | 12:00 AM

Q Dear Doc, I know this dengue thing as a big deal going around, so when I felt ‘mash up’ last week, like a truck hit me, I was sure it caught me. So I went to the doctor and instead was told I have the flu! Now, I’m not upset, but how is somebody to know the difference, because if I knew, I would have just stayed home and saved my money.


A That is a very good question. To be completely honest, it is very difficult to tell the difference.

The reason is that both dengue and the flu are caused by viruses, so the symptoms are very similar. The key difference however, would be the presence or absence of respiratory symptoms.

Influenza, which we commonly call the flu, is a highly contagious illness that occurs in both children and adults. It is spread easily from person to person by coughing, sneezing, or touching surfaces.

Flu symptoms will vary from person to person but commonly includes:

● Fever (temperature higher than 100ºF, or 37.8ºC).

● Headache and muscle aches.

● Fatigue.

● Cough and sore throat may also be present.

People who have the flu usually have a fever that lasts two to five days. Most persons will also have muscle aches, as well as cold-like symptoms such as a runny nose and a sore throat.

If you have dengue, you tend to have a higher fever, usually higher than 38.5ºC, and are less likely to have cold-like symptoms. With dengue you may also have gastrointestinal symptoms, including loss of appetite, nausea, vomiting, abdominal pain, and diarrhoea, which you typically do not get with a flu.

With the flu, symptoms usually improve over two to five days, but can last for a week or more. The weakness and fatigue may also persist for several weeks after as well.

The flu is usually diagnosed based on the symptoms of fever, cough, and muscle aches. Lab testing is not typically performed, except in certain cases, such as a new influenza outbreak.

Flu complications

Complications of influenza occur in some people. Pneumonia is the most common complication. Pneumonia is a serious infection of the lungs and is more likely to occur in young children, people over the age of 65, people who live in long-term care facilities (nursing homes) and those with other illnesses such as diabetes or conditions affecting the heart or lungs. Pneumonia is also more common in people with weakened immune systems, such as those who have had a transplant. (See ‘Patient education: Pneumonia in adults – Beyond the Basics’.)

Most persons who have the flu will recover within one to two weeks without treatment, but serious complications of the flu can occur. It is advised to visit your doctor if you experience the following:

● Shortness of breath or having trouble breathing.

● Pain or pressure in your chest or stomach.

● Dehydration, dizziness when standing or not passing urine.

● Feeling confused.

● Severe vomiting or inability to drink enough fluids.

By treating the symptoms of the flu, it will help you to feel better, but it will not make the flu go away faster. To do this you can:

● Rest until the flu is fully resolved, especially if the illness has been severe.

● Drink enough fluids so that you do not become dehydrated. If you are drinking enough, your pee will be light yellow and nearly colourless, and you should pass urine every three to five hours.

● Acetaminophen (Panadol/Tylenol) can relieve fever, headache and muscle aches. Do not take aspirin and medicines that include aspirin.

● Cough medicines can be helpful, however, the cough usually resolves without treatment.

● Antiviral medicines can be used to treat or prevent the flu. When used to treat the flu, it will not prevent flu symptoms from occurring, but it will reduce the severity and duration of symptoms by about a day. Not every person with the flu needs antiviral medicine, and the decision is based upon the severity of the illness, and risk factors for developing complications of the flu.

If you are only mildly ill and have no risk factors for complications and want to be treated with an antiviral medication, it will be offered if you have had symptoms for 48 hours or less, but not if you have had symptoms for more than 48 hours.

Antibiotics are NOT useful for treating viral illnesses such as the flu. Antibiotics should only be used if there is a bacterial complication of the flu such as bacterial pneumonia, ear infection, or sinusitis.

If you are concerned about getting the flu again, you can discuss with your doctor about the flu vaccine.