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Adolescent dengue: Clinico-demographic insights and outcome trends
*Corresponding author: K. T. Sivaranjini, Department of Paediatrics, Karnataka Medical College and Research Institute, Hubli, Karnataka, India. sivaranjini.harihara@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Sivaranjini KT, Shilpa C, Madhu PK, Raghavendra G, Ratageri VH. Adolescent dengue: Clinico-demographic insights and outcome trends. Karnataka Paediatr J. 2025;40:147-52. doi: 10.25259/KPJ_30_2025
Abstract
Objectives:
Dengue fever (DF) is a mosquito-borne viral illness that poses a major public health challenge in tropical and subtropical regions. The recent surge in dengue cases, along with limited clinical data on its impact in the adolescent population, prompted this study to evaluate the clinical and laboratory profiles, complications and outcomes among hospitalised adolescents with dengue.
Material and Methods:
This prospective observational study was conducted over 7 months at a tertiary care hospital in North Karnataka. All patients aged 10–18 years with serologically confirmed dengue infection (Dengue non-structural protein 1 monoclonal antibodies enzyme-linked immunosorbent assay and/or immunoglobulin M positive) were enrolled. Detailed demographic, clinical, laboratory and outcome data were recorded using a structured pro forma and analysed using Microsoft Excel and Statistical Package for the Social Sciences.
Results:
A total of 113 patients met the inclusion criteria. Based on the World Health Organization classification, 87 patients (77%) had dengue with warning signs, 18 (16%) had severe dengue and 8 (7%) had dengue without warning signs. The mean age was 13.7 years, with a male-to-female ratio of 1.6:1. Common clinical features included fever (98.2%), abdominal pain (68.1%), myalgia (48.6%), headache (48.6%), hepatomegaly (17.6%) and bleeding manifestations (8%). Among laboratory parameters, leukopenia (<4,000/cumm) was observed in 82 cases (72.5%), thrombocytopenia (<1 lakh/cumm) in 75 cases (66.9%) and the mean haematocrit was 38.5%. The most frequent complication in severe dengue cases was hypotension (72.2%), followed by polyserositis (38.9%), encephalitis (22.2%) and myocarditis (11.1%). Mortality was recorded in 2 patients (1.8%). The findings indicate that dengue tends to be more severe during adolescence.
Conclusion:
DF predominantly affects adolescent males and is associated with a higher rate of complications in this age group. Severe dengue in adolescents carries a significant risk of adverse outcomes, highlighting the need for early recognition, close monitoring and prompt management to reduce morbidity and mortality.
Keywords
Adolescents
Dengue fever
Morbidity
Mortality
INTRODUCTION
Dengue fever (DF) remains a significant public health challenge, particularly in tropical and subtropical areas such as Southeast Asia, where the dengue virus is primarily transmitted by Aedes mosquitoes (Aedes aegypti and Aedes albopictus) that thrive in these climates. Southeast Asia alone accounts for more than 75% of global dengue cases. The incidence of dengue has escalated markedly, with a 30-fold global increase over the past five decades and a notable surge in the past 30 years. India contributes nearly 34% to the global dengue burden.[1] Notably, 50–90% of initial dengue infections are asymptomatic. When symptoms are present, they can vary from a general febrile illness to the typical clinical picture of classical DF.[2]
In 2023, Karnataka reported 19,300 dengue cases – its highest count in a decade. Accurate assessment of clinical and laboratory features is essential for effective diagnosis and management.[3] Adolescents, representing a transitional age group between childhood and adulthood, have distinct physiological responses and healthcare needs. Recent epidemiological data suggest that adolescents are increasingly representing a growing proportion of dengue cases, particularly in endemic regions. A multicentric study in Asia reported that dengue severity and hospitalisation rates were significantly higher among adolescents compared to younger children, highlighting the unique vulnerability of this subgroup.[4]
In India, national surveillance data have shown a gradual shift in dengue burden toward older children and adolescents, with adolescents increasingly presenting with severe manifestations, such as plasma leakage, bleeding and organ involvement.[5]
Despite this, clinical data focusing exclusively on adolescents remain sparse, with most studies combining paediatric and adult populations. Given their distinct physiological and immunological profiles, adolescents warrant targeted evaluation to better understand disease progression, clinical features, and outcomes.
Analysing the clinicodemographic profile and outcomes in this group is vital for optimising targeted interventions. This study examines the clinical and laboratory characteristics, as well as outcomes, of hospitalised dengue patients aged 10– 18 years, admitted between January and July 2024.
MATERIAL AND METHODS
Study design and setting
This prospective observational study was conducted between 1 January 2024 and 31 July 2024, in the Department of Paediatrics at Karnataka Medical College and Research Institute, Hubballi. The study enrolled patients aged 10–18 years who were admitted with serologically confirmed dengue infection, diagnosed using dengue non-structural protein 1 (NS1) monoclonal antibodies enzyme-linked immunosorbent assay and/or immunoglobulin M (IgM) antibody testing.
Methodology
Eligible participants were included after obtaining informed consent from their parents and assent from the adolescents. Detailed clinical and demographic data were collected using a structured case record form, which captured presenting symptoms, physical examination findings, laboratory results and radiological investigations. A comprehensive clinical assessment was performed at admission, followed by continuous monitoring throughout the hospital stay to evaluate disease progression.
Patients were categorised based on the World Health Organization (WHO) classification into three groups:
Dengue without warning signs – laboratory-confirmed dengue cases without evidence of plasma leakage.
Dengue with warning signs – cases exhibiting symptoms such as severe abdominal pain or tenderness, persistent vomiting, clinical signs of fluid accumulation, mucosal bleeding, lethargy or restlessness, hepatomegaly (>2 cm) and rising haematocrit with a rapid fall in platelet count.
Severe dengue – characterised by plasma leakage leading to shock, respiratory distress, severe bleeding or organ involvement, including altered mental status.
Monitoring and measurements
Vital signs were monitored in accordance with WHO guidelines. Abdominal ultrasonography was performed in patients presenting with abdominal pain using a trained sonologist. Management and classification of cases followed WHO recommendations. Data were entered and analysed using IBM Statistical Package for the Social Sciences Statistics Version 28 (IBM Corp., Armonk, NY).
RESULTS
A total of 113 adolescent patients were included in this study [Figure 1]. According to the WHO classification, 8 patients (7%) were diagnosed with DF, 87 (77%) with DF with warning signs (DFWS) and 18 (16%) with severe dengue (DS). The mean age of the study population was 13.7 years.
- Study flow chart. LAMA: Left against medical advice.
The male-to-female ratio was 1.6:1, with a higher incidence of severe cases observed among males.
Epidemiological characteristics
Table 1 presents the epidemiological distribution of cases based on disease severity. Among the DF group, 5 out of 8 patients (62.5%) were in the 14–16 years age group. In contrast, the majority of DFWS cases, 58 out of 87 (66.7%), belonged to the 10–13 years age group. Similarly, 6 out of 18 (33.3%) patients with DS were aged 10–13 years.
| Determinants | DF (n=8) (%) | DFWS (n=87) (%) | DS (n=18) (%) |
|---|---|---|---|
| Age group (years) | |||
| 10–13 | 2 (25.0) | 58 (66.7) | 6 (33.3) |
| 14–16 | 5 (62.5) | 13 (14.9) | 5 (27.8) |
| 17–19 | 1 (12.5) | 16 (18.4) | 7 (38.9) |
| Gender | |||
| Female | 2 (25.0) | 37 (42.5) | 4 (22.2) |
| Male | 6 (75.0) | 50 (57.5) | 14 (77.8) |
| BMI classification | |||
| Normal | 7 (87.5) | 71 (81.6) | 17 (94.4) |
| 3rd –10th percentile | 0 (0.0) | 5 (5.7) | 1 (5.6) |
| <3rd percentile | 1 (12.5) | 11 (12.6) | 0 (0.0) |
| Clinical features | |||
| Fever | 7 (87.5) | 86 (98.9) | 18 (100.0) |
| Loose stools | 1 (12.5) | 7 (8.0) | 2 (11.1) |
| Myalgia/headache | 6 (75.0) | 38 (43.7) | 11 (61.1) |
| Abdominal pain | 8 (100.0) | 52 (60.9) | 8 (44.4) |
| Hepatomegaly | 0 (0.0) | 14 (16.1) | 6 (33.3) |
| Bleeding manifestations | |||
| None | 8 (100.0) | 84 (96.7) | 11 (61.1) |
| Epistaxis | 0 (0.0) | 1 (1.1) | 1 (5.5) |
| Melena | 0 (0.0) | 2 (2.2) | 5 (27.9) |
| Haematemesis+Melena | 0 (0.0) | 0 (0.0) | 1 (5.5) |
| Vomiting | 0 (0.0) | 51 (58.6) | 12 (66.7) |
| Hospital stay (days) | |||
| 0–3 | 6 (75.0) | 37 (42.5) | 4 (22.2) |
| 3–6 | 2 (25.0) | 46 (52.9) | 9 (50.0) |
| >6 | 0 (0.0) | 4 (4.6) | 5 (27.8) |
| Mean duration±SD | — | — | 4.32±2.86 |
(Values expressed as number of cases with percentages in parentheses). SD: Standard deviation, DF: Dengue fever, DFWS: Dengue fever with warning signs, DS: Severe dengue, BMI: Body mass index
Male predominance was noted across all severity categories. Specifically, males constituted 6 of 8 (75.0%) DF cases, 50 of 87 (57.5%) DFWS cases and 14 of 18 (77.8%) DS cases.
Clinical features
Patients with DF most frequently presented with abdominal pain (8/8; 100.0%), followed by fever (7/8; 87.5%) and myalgia/headache (6/8; 75.0%).
Those with DFWS commonly reported fever (86/87; 98.9%), vomiting (51/87; 58.6%), abdominal pain (52/87; 60.9%), myalgia or headache (38/87; 43.7%), hepatomegaly (14/87; 16.1%), and melena (2/87; 2.2%).
Patients with severe dengue (DS) consistently presented with fever (18/18; 100.0%), followed by vomiting (12/18; 66.7%), myalgia or headache (11/18; 61.1%), hepatomegaly (6/18; 33.3%), and melena (5/18; 27.9%).
Hospital stay duration
Among DF patients, 6 out of 8 (75.0%) had a hospital stay of 0–3 days.
In the DFWS group, 46 out of 87 (52.9%) were hospitalised for 3–6 days.
Among DS cases, 9 out of 18 (50.0%) had a hospital stay ranging from 3 to 6 days.
Laboratory findings and management
As summarised in Table 2, key laboratory investigations, including haematocrit (HCT), total leukocyte count (TLC) and platelet count, were performed for all patients. Leukopenia (TLC <4,000/cumm) was identified in 82 cases (72.5%), while thrombocytopenia (platelet count <1 lakh/cumm) was noted in 75 patients (66.9%). The mean haematocrit value across the study population was 38.5%.
| Parameter | DF (n=8) (%) | DFWS (n=87) (%) | DS (n=18) (%) |
|---|---|---|---|
| Polyserositis | 0 (0.0) | 2 (2.3) | 7 (38.9) |
| Encephalitis | 0 (0.0) | 0 (0.0) | 4 (22.2) |
| Myocarditis | 0 (0.0) | 0 (0.0) | 2 (11.1) |
| Acute kidney injury | 0 (0.0) | 1 (1.1) | 1 (5.6) |
| Hypotension | 0 (0.0) | 8 (9.2) | 13 (72.2) |
| Antipyretics | 8 (100.0) | 87 (100.0) | 18 (100.0) |
| Intravenous fluids | 6 (75.0) | 62 (71.3) | 16 (88.9) |
| Blood products (FFP) | 0 (0.0) | 1 (1.1) | 2 (11.2) |
| Blood products (RDP) | 0 (0.0) | 1 (1.1) | 8 (44.5) |
| Inotropes | 0 (0.0) | 1 (1.1) | 5 (27.8) |
(Values expressed as number of cases with percentages in parentheses). FFP: Fresh frozen plasma, RDP: Random donor platelet, DF: Dengue fever, DFWS: Dengue fever with warning signs, DS: Severe dengue
Management primarily involved the use of antipyretics and intravenous fluids. In patients with severe dengue (DS), advanced interventions such as blood product transfusion and inotropic support were required in 8 (44.5%) and 5 (27.8%) cases, respectively. Among patients with DFWS, only 1 case (1.1%) received blood products – fresh frozen plasma and random donor platelets – and another 1 case (1.1%) required inotropes.
The most frequently observed complication among patients with severe dengue was hypotension, occurring in 72.2% of these cases. Other notable complications included myocarditis and encephalitis, contributing to morbidity.
Serological and biochemical investigations
Details of serological and biochemical parameters are outlined in Table 3. The NS1 antigen was positive in 4 (50.0%), 58 (66.7%) and 11 (61.1%) cases of DF, DFWS and DS, respectively. IgM antibodies were detected in 4 (50.0%) DF cases, 35 (40.2%) DFWS cases and 10 (55.6%) DS cases.
| Investigation parameter | DF (n=8) (%) | DFWS (n=87) (%) | DS (n=18) (%) |
|---|---|---|---|
| NS1 positive | 4 (50.0) | 58 (66.7) | 11 (61.1) |
| IgM positive | 4 (50.0) | 35 (40.2) | 10 (55.6) |
| TLC <4,000 cells/mm3 | 6 (75.0) | 65 (74.7) | 11 (61.1) |
| TLC 4,000–11,000 cells/mm3 | 2 (25.0) | 21 (24.1) | 7 (38.9) |
| TLC >11,000 cells/mm3 | 0 (0.0) | 1 (1.1) | 0 (0.0) |
| Mean TLC±SD | — | — | 3559.56±1945.607 |
| TPC <50,000 | 0 (0.0) | 26 (29.9) | 12 (66.7) |
| TPC 50,001–100,000 | 4 (50.0) | 31 (35.6) | 2 (11.1) |
| TPC >100,000 | 4 (50.0) | 30 (34.5) | 4 (22.2) |
| Mean TPC±SD | — | — | 98947±104154.274 |
| HCT >36.3% | 4 (50.0) | 32 (36.8) | 2 (11.1) |
| HCT <36.3% | 4 (50.0) | 55 (63.2) | 16 (88.9) |
| Mean HCT±SD | — | — | 38.525±6.0005 |
| SGPT <50 IU/L | 5 (62.5) | 63 (72.4) | 10 (55.6) |
| SGPT 50–200 IU/L | 2 (25.0) | 21 (24.1) | 6 (33.3) |
| SGPT 200–1,000 IU/L | 1 (12.5) | 3 (3.4) | 2 (11.1) |
| SGPT >1,000 IU/L | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Mean SGPT±SD | — | — | 52.112±85.1585 |
| SGOT <50 IU/L | 5 (62.5) | 44 (50.6) | 7 (38.9) |
| SGOT 50–200 IU/L | 1 (12.5) | 34 (39.1) | 8 (44.4) |
| SGOT 200–1,000 IU/L | 2 (25.0) | 9 (10.3) | 3 (16.7) |
| SGOT >1,000 IU/L | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Mean SGOT±SD | — | — | 98.817±150.8857 |
(Values expressed as number of cases with percentages in parentheses). SD: Standard deviation, IgM: Immunoglobulin M, TLC: Total leukocyte count, TPC: Total phenolic content, SGPT: Serum glutamate pyruvate transaminase, SGOT: Serum glutamic-oxaloacetic transaminase, DF: Dengue fever, DFWS: Dengue fever with warning signs, HCT: Haematocrit, DS: Severe dengue, NS1: Nonstructural protein 1
TLC <4,000/cumm was observed in 6 (75.0%) DF, 65 (74.7%) DFWS and 11 (61.1%) DS patients. Platelet counts <50,000/cumm were seen in 26 (29.9%) DFWS and 12 (66.7%) DS patients. HCT values <36.3% were recorded in 55 (63.2%) DFWS and 16 (88.9%) DS patients. Elevated SGPT levels (200–1,000 IU/L) were noted in 3 (3.4%) DFWS and 2 (11.1%) DS cases, while SGOT levels in the same range were found in 9 (10.3%) DFWS and 3 (16.7%) DS patients.
Outcomes
Among the 113 patients, 2 (11.1%) left against medical advice and 2 (11.1%) succumbed to complications associated with severe dengue. The predominance of warning signs and serious complications in this adolescent cohort highlights the potential severity of dengue infection in this age group.
DISCUSSION
This study aimed to evaluate the clinicodemographic profile, laboratory characteristics and clinical outcomes of hospitalised dengue patients aged 10–18 years over 7 months. Patients were categorised using the WHO classification into DF, DFWS and severe dengue (DS). Notably, clinical severity and complications were more frequent in adolescents compared to other age groups treated at our institution. Comparative studies across age groups would further substantiate these findings.
A male predominance was observed, with a male-to-female ratio of 1.6:1, consistent with previous studies by Das et al. (2017) and Sharma et al. (2020).[6,7] This may be attributed to increased outdoor exposure among adolescent males due to activities such as sports, labour and social interaction, increasing their risk of contact with Aedes mosquitoes – the primary dengue vectors.
Fever emerged as the most common presenting symptom, observed in 98.2% of cases, in line with the findings of Ghosh et al. (2019) and Mishra et al. (2021).[8,9] Abdominal pain was reported in 68.1% of patients, which is higher than the 54.3% reported by Das et al. (2017)[6] but comparable to the 65% reported by Singh et al. (2022).[10] Myalgia and headache were noted in 48.6% of patients. In comparison, Ghosh et al.[8] reported a higher prevalence of myalgia (72%), and Sharma et al. noted headache in 51% of cases.[7] Regional differences in climate, virus strains and socioeconomic factors may account for the variation in symptom profiles.
Hepatomegaly was seen in 17.6% of our cases, lower than the 43.8% noted by Das et al. but closely matching Mishra et al.’s 15%.[6,8] Bleeding manifestations were observed in 8% of patients in our cohort, lower than the 22% reported by Das et al. and 12% reported by Sharma et al.[6,7] These differences may reflect improvements in supportive care, as well as early identification and intervention.[6,7]
Leukopenia was present in 72.5% of our patients, significantly higher than the 25.8% reported by Das et al. and 48.5% by Singh et al.[6,10] Thrombocytopenia was observed in 66.9%, also higher than the 27.5% reported by Das et al., but similar to the 62% noted by Mishra et al.[6,9] These differences may be due to variation in disease severity, the timing of presentation or circulating dengue serotypes during the study period.
The mean HCT value was 38.5%. Das et al. reported raised HCT in 34% of cases but did not specify a mean value.[6] Among complications, hypotension was the most frequent, affecting 72.2% of patients with severe dengue, similar to the 68% observed by Ghosh et al.[8] The inclusion of hospitalised patients with more severe disease may have contributed to a higher complication rate.
The case fatality rate was 1.8%, with two deaths among 113 patients, which is in line with the findings of Mishra et al. (1.5%) and Sharma et al. (1.2%).[7,9] Improved awareness, timely referral, fluid management and adherence to WHO guidelines likely contributed to these favourable outcomes.[11] While our findings align with other Indian studies regarding male predominance and fever as a predominant symptom, we noted some discrepancies in the frequency of other clinical manifestations and complications. These differences underscore the need for regional epidemiological studies to understand dengue’s diverse presentations better and to guide context-specific public health responses. This study, based in a tertiary Centre in North Karnataka, captures a broad demographic, including urban and rural populations, enhancing the generalizability of the findings.
Study limitations
This study focused exclusively on hospitalised patients, potentially excluding milder cases treated in outpatient settings. As a result, the findings may overrepresent severe presentations and complications. In addition, serotyping of the dengue virus (e.g., DEN-1 to DEN-4) was not performed, which limits insight into genotype-specific disease patterns. Long-term outcomes and sequelae among adolescent patients were not evaluated, leaving an important gap in understanding the broader impact of dengue.
What this study adds
Health systems should ensure that dengue management protocols are adapted to include age-specific considerations for adolescents, particularly regarding fluid therapy and monitoring parameters.
From a public health perspective, there is a need to enhance dengue surveillance systems to capture age-disaggregated data that reflect adolescent-specific trends in disease incidence, severity and outcomes. School-based health education and vector control initiatives targeting adolescents can promote early health-seeking behaviour and reduce transmission risks. Incorporating adolescent-friendly communication strategies in public awareness campaigns can further improve engagement and compliance with prevention measures.
Finally, investment in research focusing on adolescent immunological responses to dengue, vaccine responsiveness and long-term outcomes will be critical in informing both clinical guidelines and public health policy in endemic regions. Future studies comparing clinical profiles across different age groups and incorporating virological data would enhance our understanding and inform more effective public health strategies.
CONCLUSION
DF has a significant impact on adolescents, particularly males, possibly due to increased outdoor exposure. Severe dengue in this age group is associated with a higher rate of complications, including hypotension and haematological abnormalities. Early diagnosis, vigilant monitoring and timely intervention based on the WHO guidelines are critical to improving clinical outcomes and reducing mortality.
Ethical approval:
The research/study complied with the Helsinki Declaration of 1964.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that they have used artificial intelligence (AI)-assisted technology solely for language refinement and to improve the clarity of writing. No AI assistance was employed in the generation of scientific content, data analysis or interpretation.
Financial support and sponsorship: Nil.
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