The diagnosis of dengue fever requires an integration of clinical presentation, epidemiological history, and laboratory test results. During the diagnostic process, physicians first evaluate the patient's symptoms and their development timeline through detailed history-taking, and confirm exposure history to endemic areas. Laboratory tests are crucial evidence, capable of detecting the presence of viral antigens or antibodies, thereby confirming the diagnosis.
Early diagnosis is vital for preventing severe complications. When patients present with high fever, skin pain, or rash, immediate systematic assessment should be conducted. The diagnostic process typically involves two stages: initial screening and definitive diagnosis, utilizing a combination of different testing tools to improve accuracy.
During clinical evaluation, physicians primarily observe the timeline and severity of symptoms. Typical dengue symptoms include acute fever (39-40°C), headache, retro-orbital pain, myalgia and arthralgia (commonly known as "breakbone fever"), and erythema on the neck or chest and back. Special attention is paid to bleeding tendencies during the "defervescence phase," which may indicate worsening of the condition.
Collecting epidemiological history is fundamental to diagnosis. Detailed inquiries about activities in the past two weeks are necessary, including visits to endemic regions such as South Asia, Southeast Asia, Central and South America, or contact with confirmed cases. Living in tropical areas or recent participation in outdoor activities significantly increases infection risk.
Physical examination includes noting the morphology and distribution of rashes, and assessing signs of bleeding such as gum bleeding, increased menstrual flow, or subcutaneous ecchymosis. Dynamic changes in hematocrit and platelet counts help determine if the patient is entering the "shock phase," which is particularly critical for classification diagnosis.
Laboratory diagnosis is divided into acute and convalescent phases. During the first five days of fever, detection of NS1 antigen in serum can provide rapid results within 24-48 hours of symptom onset. A positive result allows immediate implementation of isolation and supportive treatment.
Serological testing is another key tool. IgM antibodies typically peak 5-7 days after fever onset and persist for several weeks; IgG antibodies increase within months after infection. Physicians often perform "paired serum" testing, comparing antibody levels between the acute and convalescent phases to confirm the timing of infection.
Viral nucleic acid testing (such as RT-PCR) can directly detect viral RNA, suitable within the first 3-5 days of fever. Although highly sensitive, this method requires specialized equipment and is more costly, usually used for suspected severe or complex cases. Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can indirectly reflect systemic inflammatory responses caused by the virus.
Rapid diagnostic test kits are important tools in primary healthcare, capable of detecting NS1 antigen and IgM/IgG antibodies within 15 minutes. These tools are suitable for resource-limited areas but may require combination with other tests to rule out false positives.
Electronic assessment platforms are increasingly used for large-scale screening. Some healthcare systems utilize instant messaging software to integrate symptom questionnaires and GPS location data, quickly identifying high-risk cases. While these digital tools improve screening efficiency, they need to be interpreted by medical professionals.
Imaging examinations, though not primary diagnostic tools, can assist in excluding complications such as pneumonia via chest X-ray, or assess for ascites or organ enlargement with ultrasound. These auxiliary tests provide multi-dimensional information for complex cases.
Dengue fever must be distinguished from influenza, Chikungunya virus infection, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Influenza patients usually do not exhibit significant platelet decline, while joint pain in chikungunya tends to be more severe and persistent.
When differentiating, attention should be paid to the severity of the disease: dengue hemorrhagic fever patients may experience mucosal bleeding or a hematocrit increase >20%, whereas dengue shock syndrome is characterized by hypotension and peripheral circulatory failure. These clinical indicators are central to classification diagnosis.
Other diseases to exclude include yellow fever, Zika virus infection, and malaria. For example, malaria often presents with cyclical fever and parasitemia in peripheral blood, while yellow fever may show abnormal liver function tests. Physicians need to cross-reference laboratory data to confirm the diagnosis.
Early detection can effectively reduce mortality, as the critical period for severe progression typically occurs between days 3-7 after fever onset. Confirming the diagnosis early allows healthcare teams to monitor key indicators such as blood pressure, hematocrit, and urine output, and to provide supportive treatment promptly.
On a public health level, early diagnosis aids in tracking epidemic hotspots. Through real-time reporting systems, health authorities can quickly initiate mosquito control measures to interrupt the transmission chain. This is crucial for controlling cluster outbreaks.
Patient education is also a part of early diagnosis. Community health education that raises awareness of warning signs like "fever plus three pains" can prompt patients to seek medical attention early. This collaborative approach between healthcare providers and the community can shorten diagnostic delays and improve treatment outcomes.
Blood tests are the primary method for diagnosing dengue fever, but physicians usually combine clinical symptoms (such as high fever, headache, muscle pain) and epidemiological history (such as recent travel to endemic areas) for comprehensive assessment. During the acute phase, blood cell counts and antibody tests are particularly important, but definitive diagnosis still relies on viral nucleic acid detection or antibody changes.
Why might some patients have negative serum test results in the early stage?In the initial 72 hours of illness, viral antibodies may not yet be produced, leading to negative serological test results. It is recommended to repeat blood tests after 3-5 days if symptoms persist, to improve diagnostic accuracy. Additionally, low viral load or improper blood sampling timing can affect results.
Is it safe for suspected dengue patients to reduce fever at home?It is not recommended to self-administer aspirin or non-steroidal anti-inflammatory drugs (such as ibuprofen), as they may increase bleeding risk. Physical cooling methods (such as cold compresses) and hydration are advised, and patients should seek medical attention promptly to rule out severe complications. High fever lasting more than 3 days or accompanied by bleeding signs warrants close vigilance.
Does previous dengue infection make subsequent infections more difficult to diagnose?Reinfection may involve antibody-dependent enhancement, leading to more severe symptoms. In such cases, serological tests need to distinguish between new and old antibody responses. Physicians may also use viral nucleic acid testing or compare serum samples from different time points to confirm the diagnosis.
Why do some regions require suspected cases to be hospitalized for observation?Initial symptoms of dengue can resemble common colds, but the risk of severe disease is high. Hospitalization allows close monitoring of platelet counts, blood viscosity, and other indicators, preventing missed opportunities for timely treatment of hemorrhagic fever or shock. Especially during outbreaks, this measure can significantly reduce mortality rates.
%201.svg)
Copyright © 2025 MedFrontiers. All Rights Reserved.
