42-Year-Old Male With Widespread Rash, Cough and Vomiting

Published on February 1, 2026

Differential Diagnosis

• Influenza
• Leptospirosis
• Hantavirus
• Dengue fever
• Malaria
• Typhoid fever
• Acute HIV infection

Diagnosis

The correct diagnosis is Dengue fever. Dengue fever is a viral illness transmitted by mosquitoes in tropical and subtropical regions. It is most often diagnosed clinically, with confirmation through PCR or IgM testing, if available. It presents in three phases:

1. Febrile Phase (3–7 days): High fever (≥38.5°C), headache, retro-orbital pain, myalgias, arthralgias, and a transient non-pruritic macular rash (2–5 days after fever onset).
2. Critical Phase (seen in a minority of patients, typically children and younger adults): Plasma leakage which can lead to bleeding, shock, and organ failure. Symptoms include severe vomiting, abdominal pain, hepatomegaly, pleural effusion, ascites, mucosal bleeding, and lethargy.
3. Recovery Phase (2–4 days): Plasma leakage and hemorrhage resolve, vital signs stabilize, and accumulated fluids are resorbed. A pruritic, confluent rash may appear. Fatigue can persist for weeks in adults.

What To Look For

• Travel history to a tropical or sub-tropical area should increase your clinical suspicion for Dengue.
• Physical exam findings depend on which phase of illness the patient presents and may include rash, conjunctivitis, pharyngeal erythema and hemorrhagic features such as petechiae, ecchymosis, vaginal or gastrointestinal bleeding.
• A positive tourniquet test can support a clinical diagnosis of Dengue and is performed by inflating a blood pressure cuff on the arm to midway between systolic and diastolic blood pressures for five minutes and reveals petechiae 1 – 2 minutes after deflating the cuff.
• Associated laboratory findings include leukopenia, thrombocytopenia and elevated aminotransferases.

Pearls For Urgent Care Management

• Outpatient management is appropriate for patients with a presumed diagnosis of Dengue in the absence of warning signs for hemorrhage or shock.
• Patients should be instructed to take plenty of fluids and watch for signs of dehydration which would warrant prompt clinical evaluation.
• Fevers and myalgias can be managed with acetaminophen – nonsteroidal anti-inflammatory drugs and aspirin-based products should not be used out of concern for their potential effect on platelet function and the potential increased risk for bleeding.
• Close follow-up is needed after the initial febrile phase to monitor for dehydration; consider serial blood counts to monitor for thrombocytopenia.
• Advise patients to seek prompt urgent or emergent care if fever persists or if new symptoms develop such as severe abdominal pain, weakness, persistent vomiting, bleeding, altered mental status or difficulty breathing.

Read More

• Rising Dengue Fever Cases Outpacing Last Year
• The Traveling Patient
• A 32-Year-Old with Fever, Cough, Arthralgia, and Photophobia