Symptoms of Dengue Fever

Dengue fever is a viral infectious disease transmitted by mosquitoes, with symptoms that vary greatly in severity, ranging from asymptomatic to life-threatening hemorrhagic fever. Symptoms typically appear within 3 to 14 days after a mosquito bite, initially resembling the common cold, but can rapidly worsen.

Key symptoms include high fever, severe headache, and muscle and joint pain, often referred to as "breakbone fever." Some patients may develop rash or lymphadenopathy during the febrile phase. If not diagnosed and treated promptly, severe cases may progress to shock syndrome or internal bleeding, making it crucial to recognize these symptoms early.

This article will analyze the progression of dengue symptoms in stages, helping readers identify warning signs at different phases and emphasizing the importance of timely medical intervention. Understanding the patterns of symptom variation aids early detection and prevention of complications.

Early Symptoms and Signs

Early symptoms of dengue usually appear 4 to 7 days after infection. These initial signs may resemble influenza, but their distinctive combination provides diagnostic clues. Typical early symptoms include:

• High fever: Body temperature often rises to 39-40°C within hours, accompanied by chills and malaise
• Headache: Tenderness in the forehead and occipital region, possibly radiating behind the eyes
• Muscle and joint pain: Especially in the lower back, limbs, and neck, which can be severe enough to affect daily activities

Other common signs at this stage include lymphadenopathy (especially in the neck and axilla), sore throat, and mild conjunctival injection. About 30% of patients develop skin redness (rash) between days 3-5 of fever, which may appear as scattered erythema or reticulated rash, often mistaken for allergic reactions.

Common Symptoms

During the peak phase (usually days 3-7 after onset), patients exhibit more characteristic symptoms:

• Persistent high fever: Body temperature exceeding 39°C for more than 48 hours
• Bleeding tendencies: Gingival bleeding, increased menstrual flow, petechiae
• Gastrointestinal symptoms: Nausea, vomiting, diarrhea, or severe abdominal pain

Approximately 50% of patients develop a distinctive rash after fever onset, typically starting on the chest or abdomen and spreading to the limbs. This pale red maculopapular rash may reappear after defervescence and resolve within days. Some patients also show lymphadenopathy and leukopenia in laboratory tests.

Disease Progression and Symptom Changes

Acute Phase Symptoms

In the acute stage (days 3-7), symptoms may suddenly intensify, requiring close monitoring:

• Fever may suddenly drop, but bleeding tendencies worsen
• Development of the "Three Pain Syndrome": bone pain, headache, and eye pain
• Possible hepatomegaly and abnormal liver function tests

Signs of Severe Complications

About 5% of cases may progress to dengue hemorrhagic fever or dengue shock syndrome, with symptoms including:

• Multiple ecchymoses and internal bleeding signs: hematemesis, melena, hematuria
• Sudden blood pressure drop causing dizziness, cold sweat, and cold extremities
• Altered mental status or agitation indicating central nervous system involvement

In severe cases, multi-organ failure such as pulmonary edema or liver failure may occur. Symptoms change rapidly at this stage, requiring immediate hemodynamic monitoring and intensive care.

When to Seek Medical Attention

Seek immediate medical care if any of the following occur:

• Persistent high fever exceeding 3 days with severe muscle pain
• Unexplained bleeding (e.g., gum bleeding, petechiae)
• Vomiting more than 3 times per hour or inability to retain fluids

If symptoms worsen within 24 hours after defervescence, it may indicate severe complications. High-risk groups (such as the elderly, patients with chronic illnesses, or those previously infected with dengue) should seek prompt medical evaluation if typical symptoms appear.

Even if symptoms seem mild, if recent travel to endemic areas or mosquito bites have occurred, a specialized examination is recommended. Early diagnosis can significantly reduce the risk of complications, with blood tests and viral antibody testing being key diagnostic tools.

 

Frequently Asked Questions

What are the effects of self-medicating with antipyretics in dengue patients?

Self-medicating with non-steroidal anti-inflammatory drugs (such as aspirin or ibuprofen) may increase bleeding risk, as dengue can impair platelet function. It is recommended to use acetaminophen-based medications for fever reduction and to monitor for signs of bleeding or petechiae.

When is emergency medical attention necessary? What are key signs of severe complications?

If persistent vomiting, severe abdominal pain, significantly decreased urine output, or skin bruising occur, it may have progressed to dengue hemorrhagic fever or shock syndrome, requiring immediate hospitalization. These signs indicate increased vascular permeability or rapid platelet decline, necessitating monitoring and fluid therapy.

Besides mosquito prevention, what daily measures can reduce infection risk?

Eliminating unnecessary standing water containers, using mosquito nets, and wearing long-sleeved clothing are basic preventive measures. Additionally, placing mosquito-repellent plants (such as citronella) indoors and regularly spraying insecticides in shaded areas can help break the breeding cycle of disease-carrying mosquitoes.

Will recovery confer lifelong immunity? How do different serotypes affect reinfection?

Infection with a single serotype provides immunity only against that serotype; the other three serotypes can still cause infection. Reinfection with a different serotype may increase the risk of severe disease due to antibody-dependent enhancement (ADE). Therefore, continued mosquito avoidance is necessary even after recovery.

What contact precautions should patients and caregivers observe during infectious periods?

Patients are contagious during the febrile period. Caregivers should wear long-sleeved clothing and use DEET-containing repellents. Hands should be washed immediately after contact, and direct contact with blood or bodily fluids should be avoided until at least one day after fever subsides.