Dengue is transmitted by a mosquito that bites during the day, is present in urban areas, and does not care that you are on holiday. Most cases resolve on their own. The reason it deserves your attention is the small number that do not — and the timing of when that becomes visible.

What it looks like

Sudden fever, typically 39°C to 40°C, plus at least two of:

  • Headache, and pain behind the eyes
  • Muscle and joint pain
  • Marked exhaustion
  • Nausea or vomiting
  • Red spots or a rash on the skin
  • Loss of taste and appetite

If you have that combination, seek medical care rather than waiting it out.

The part most travellers get wrong

The dangerous phase does not arrive at the peak of the fever. It arrives as the fever comes down — between the third and seventh day, exactly when you think you are recovering.

Go to an emergency service immediately if any of these appear:

  • Severe abdominal pain that persists
  • Vomiting that will not stop and prevents you from drinking
  • Any bleeding — gums, nose, skin
  • Dizziness, or blood pressure dropping when you stand up
  • Drowsiness, irritability or a change in behaviour

What not to take

Dengue lowers your platelets, so certain common painkillers make bleeding more likely. Avoid aspirin (AAS) and anti-inflammatories such as ibuprofen, diclofenac and nimesulide. Corticosteroids are also discouraged.

There is no antiviral for dengue. Treatment is fluids, plus a simple analgesic or antipyretic — the safe choice is the one a doctor confirms for you, especially if you already take other medication.

Reducing the risk

The mosquito bites mostly by day and breeds in standing water. Repellent on exposed skin, and accommodation with screens or air conditioning, cover most of the practical risk.

Frequently asked questions about dengue in Brazil

When are the warning signs most likely?

Between the third and seventh day, usually as the fever falls.

Can I take ibuprofen for the pain?

No. Anti-inflammatories and aspirin are contraindicated because of the drop in platelets.

Is there a treatment?

There is no antiviral. Care is based on hydration and symptom relief, with medical follow-up.

Can a doctor help online?

For assessing symptoms, guiding you and telling you when to go in person, yes. Warning signs mean in-person urgent care, not a video call.

General information, not individual medical advice. Reviewed by Dr. Marcelo Rafael Lujan, CRM-SC 42.900. Source: Ministério da Saúde, dengue clinical management guidance.

Feverish and unsure how worried to be? Speak to a Brazilian-licensed doctor online, in English, and get a clear answer on what to do next.