Dengue Fever

Dengue fever is a viral infection spread by certain mosquitoes, common in tropical and subtropical regions. It usually causes a high fever, headache, and body aches. While most cases are mild and resolve on their own, some can become severe and require urgent medical care.

What is Dengue Fever?

Dengue fever is a viral illness transmitted to humans through the bite of infected Aedes mosquitoes, primarily in tropical and subtropical areas. It typically causes a sudden high fever, severe headache, and muscle and joint pain. Most people recover fully, but some cases can progress to a more serious form called severe dengue, which needs immediate medical attention.

Dengue fever is caused by one of four related dengue viruses (DENV-1, DENV-2, DENV-3, DENV-4). It is not spread directly from person to person. The illness is most common in parts of Asia, the Pacific Islands, Latin America, and Africa. Millions of cases occur worldwide each year. After being bitten by an infected mosquito, symptoms usually appear 4 to 10 days later and typically last for 2 to 7 days. While often mild, a second infection with a different dengue virus type can increase the risk of developing severe dengue. Severe dengue, also known as dengue hemorrhagic fever, is a life-threatening complication that can lead to shock, organ damage, and even death if not treated promptly. It is crucial to recognize its warning signs.

Symptoms

Symptoms of dengue fever often appear suddenly and include a high fever, severe headache, pain behind the eyes, and intense muscle, bone, and joint pain. Some people may also develop a rash, nausea, or vomiting. These symptoms usually last for about a week, and most people recover fully with rest and fluids.

A high fever, often reaching 104°F (40°C), is a hallmark symptom. This fever can be accompanied by a severe headache and pain behind your eyes. You might also experience significant muscle, bone, or joint pain, which is why dengue is sometimes called "breakbone fever." Nausea, vomiting, and a skin rash can also occur. In some cases, mild bleeding symptoms may appear, such as bleeding gums, nosebleeds, or easy bruising. In a small number of people, severe dengue can develop. Warning signs of severe dengue usually appear 24 to 48 hours after your fever has gone down. These include severe abdominal pain, persistent vomiting, rapid breathing, bleeding from your gums or nose, blood in your vomit or stool, extreme fatigue, or restlessness. These symptoms require immediate medical attention.

Causes & risk factors

Dengue fever is caused by one of four dengue viruses, which are spread to humans through the bite of infected Aedes mosquitoes, mainly Aedes aegypti. Your risk of getting dengue increases if you live in or travel to tropical and subtropical regions where the virus is common. Having had dengue before also increases your risk of developing severe dengue if you get infected again with a different virus type.

The primary carriers of the dengue virus are female Aedes aegypti mosquitoes. Another type, Aedes albopictus, can also transmit the virus. These mosquitoes typically bite during the day, especially around dawn and dusk. You are at higher risk if you live in or travel to areas where dengue is endemic, meaning the virus is regularly found there. These regions include Southeast Asia, the Western Pacific Islands, Latin America, and the Caribbean. A significant risk factor for developing severe dengue is having a previous dengue infection. If you get infected a second time with a different type of dengue virus, your immune system's response can sometimes lead to a more serious illness. Factors like poor sanitation and lack of mosquito control in tropical areas can also contribute to the spread of the disease, as they create breeding grounds for mosquitoes.

How it's diagnosed

Dengue fever is diagnosed by a healthcare provider based on your symptoms, recent travel history to areas where dengue is common, and specific blood tests. These tests can detect the dengue virus itself or antibodies your body produces in response to the infection, confirming whether you have or recently had dengue.

When you see a doctor, they will ask about your symptoms and if you have recently traveled to a tropical or subtropical region. This information helps them consider dengue as a possible diagnosis. A blood test is essential to confirm dengue fever. This test can identify the presence of the dengue virus in your blood during the early stages of the illness. Later in the infection, blood tests can also look for antibodies, which are proteins your immune system makes to fight off the virus. Detecting these antibodies helps confirm a recent or past dengue infection. Early and accurate diagnosis is important, especially to monitor for signs of severe dengue and ensure you receive appropriate supportive care.

Treatment options

There is no specific antiviral medicine to treat dengue fever. Treatment focuses on managing symptoms and providing supportive care, such as rest, drinking plenty of fluids to prevent dehydration, and taking acetaminophen (paracetamol) for pain and fever. It is crucial to avoid aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, as these can increase the risk of bleeding.

For mild dengue, home care is usually sufficient. This includes getting plenty of rest and staying well-hydrated by drinking water, oral rehydration solutions, or fruit juices. To relieve fever and body aches, acetaminophen (Tylenol®) is recommended. However, you must avoid aspirin, ibuprofen (Advil®, Motrin®), naproxen sodium (Aleve®), and other nonsteroidal anti-inflammatory drugs (NSAIDs). These medications can thin your blood and increase the risk of bleeding complications associated with dengue. People with severe dengue require immediate hospitalization. In the hospital, treatment involves intravenous (IV) fluids to prevent or treat dehydration and shock, close monitoring of vital signs, and sometimes blood transfusions if severe bleeding occurs. The goal of treatment is to support your body's recovery and prevent the illness from becoming life-threatening. Early recognition of warning signs and prompt medical intervention are key to a positive outcome.

Recovery & outlook

Most people with dengue fever recover fully within about a week or two with proper rest and supportive care. The outlook for mild cases is generally very good. However, severe dengue is a serious condition that can lead to complications like shock, organ damage, and even death if not promptly treated.

After the initial fever subsides, some people may feel tired or weak for several weeks. It's important to continue resting and hydrating during this recovery period. For those who develop severe dengue, early recognition and aggressive medical management significantly improve the chances of a full recovery. Without timely medical intervention, severe dengue can be fatal. However, with appropriate care, the mortality rate for severe dengue can be reduced significantly. Having had dengue once provides immunity to that specific virus type, but not to the other three types. A subsequent infection with a different type can increase the risk of severe disease. Therefore, even after recovery, it's important to continue taking precautions against mosquito bites, especially if you live in or travel to endemic areas.

When to see a doctor

You should see a doctor if you develop symptoms of dengue fever, especially if you have recently traveled to an area where dengue is common. Seek immediate emergency medical care if you experience any warning signs of severe dengue, such as severe abdominal pain, persistent vomiting, rapid breathing, bleeding from your gums or nose, blood in your vomit or stool, extreme fatigue, or restlessness.

It's important to contact your healthcare provider if you suspect you have dengue, even if your symptoms seem mild. They can confirm the diagnosis and advise you on managing your symptoms safely. Pay close attention to your symptoms, especially in the 24 to 48 hours after your fever goes down. This is often when severe dengue can develop. Warning signs that require immediate medical attention include: severe stomach pain, throwing up often, breathing quickly, bleeding from your gums or nose, feeling very tired or restless, or seeing blood in your vomit or stool. Do not delay seeking emergency care if these severe symptoms appear, as prompt treatment can be life-saving. Early medical intervention can prevent serious complications and improve your chances of a full recovery.

Frequently asked questions

Can I get dengue fever more than once?

Yes, you can get dengue fever more than once. There are four different types of dengue viruses. If you get infected with one type, you develop immunity to that specific type, but not to the other three. Getting infected a second time with a different type of dengue virus can increase your risk of developing severe dengue.

Is there a vaccine for dengue fever?

Yes, there is a vaccine called Dengvaxia® available in some areas. It is approved for use in specific populations, typically individuals aged 9 to 16 years who have a confirmed history of prior dengue infection and live in areas where dengue is common. It's important to discuss with your doctor if the vaccine is right for you.

How can I protect myself from dengue if I'm traveling?

To protect yourself from dengue while traveling, use insect repellent containing DEET, picaridin, or oil of lemon eucalyptus on exposed skin. Wear long-sleeved shirts and long pants, especially during dawn and dusk when mosquitoes are most active. Stay in accommodations with air conditioning or screens on windows and doors.

What pain relievers should I avoid if I have dengue?

If you have dengue fever, you should avoid aspirin, ibuprofen (Advil®, Motrin®), naproxen sodium (Aleve®), and other nonsteroidal anti-inflammatory drugs (NSAIDs). These medications can increase your risk of bleeding complications. Acetaminophen (Tylenol®) is generally safe for pain and fever relief.

How long does it take to recover from dengue fever?

Most people with mild dengue fever recover within about one to two weeks. You might feel tired or weak for several weeks after the fever subsides. For severe dengue, recovery can take longer and requires close medical supervision.

Can dengue fever be spread directly from person to person?

No, dengue fever cannot be spread directly from person to person. The virus is transmitted only through the bite of an infected Aedes mosquito. A person with dengue can infect a mosquito if the mosquito bites them while the virus is in their bloodstream, and that mosquito can then spread it to another person.

Sources

• MedlinePlus — Dengue Fever
• Mayo Clinic — Dengue Fever
• Cochrane Library — Dengue Fever