Quick answer
Dengue usually starts with a sudden high fever (39–40 °C / 102–104 °F), intense bone and joint pain, and a telltale pain behind the eyes, almost always without cough or a runny nose. The flu starts more gradually and does cause cough, sneezing, and congestion. The combination of sudden high fever + pain behind the eyes + no cough points to dengue and should be checked the same day. At AVA Médica we offer walk-in care 7 days a week.
During the rainy season, when mosquito breeding sites increase, one of the most common questions in Piedras Negras is: is this dengue or just the flu? Confusing the two is the number one cause of delayed care, and with dengue, time matters.
The good news is that, although both cause fever, they have clear differences you can recognize at home.
The key differences
| Symptom | Dengue | Flu |
|---|---|---|
| Fever onset | Sudden, very high (39–40 °C) | Gradual, mild to moderate |
| Body aches | Intense, in bones and joints | Moderate |
| Pain behind the eyes | Yes, characteristic | No |
| Cough, congestion, sneezing | Rarely | Yes, characteristic |
| Skin rash | May appear (days 3–5) | No |
| Average duration | 5–7 days | 3–5 days |
The warning sign you shouldn't ignore
If you have a high fever that came on suddenly, marked pain behind the eyes, and NO cough or runny nose, treat it as possible dengue until a doctor says otherwise. That's the moment to get checked, not to wait and see if it passes.
Watch out for days 3 to 5
A detail that surprises many families: dengue can get worse right as the fever drops, usually between the third and fifth day. If the fever eases but the person feels worse, with abdominal pain, vomiting, or extreme fatigue, seek care immediately.
What to do in the meantime
- Stay well hydrated with water and oral rehydration solutions.
- Rest and keep an eye on the temperature.
- Avoid self-medicating: some pain relievers are not appropriate if it's dengue, so let a doctor tell you what to take.
- Get checked if the fever is very high, won't go down, or warning signs appear.
Telling dengue and the flu apart early prevents complications. At AVA Médica you can have a walk-in visit 7 days a week and, if the doctor recommends it, get your lab work done in the same place to clear up any doubts the same day.
This information is general and does not replace a medical consultation. Always consult your doctor for a personalized diagnosis and treatment.