# Febrile Rash: An Early Diagnostic Clue to Infectious Illness in Travelers Returning from Thailand

## TL;DR

A febrile rash in travelers returning from Thailand may indicate dengue, highlighting the need for early diagnosis and isolation to prevent outbreaks.

## Contribution

The paper emphasizes febrile rash as an early diagnostic clue for dengue in returning travelers.

## Key findings

- A case of dengue was confirmed in a traveler with febrile rash despite initial negative test results.
- Dengue cases in Thailand in 2023 exceeded 100,000, raising concerns about transmission to non-endemic countries.
- Immediate isolation of patients is crucial to prevent local dengue transmission and public health crises.

## Abstract

The eruption of a rash along with spiking fever in travelers returning from the tropics may be suspicious of arboviral diseases, and isolation prevent further transmission in non-endemic countries. The case presented here was seen at the Fever Clinic at the Hospital for Tropical Diseases in Bangkok, Thailand. The presenting complaints were fever, headache, myalgia, and a distinctive erythematous blanching rash. Despite a negative dengue NS1 test on the initial day, anti-dengue IgM and IgG were detectable on day five of illness. Dengue, a leading cause of traveler’s fever with rash, is of particular concern, especially during outbreaks like the one in Thailand in 2023, when the number of cases exceeded one hundred thousand over a nine-month period. The influx of 28 million travelers in 2023, many with naive immunity to many arboviruses, raises fear of transmission to temperate regions, including to countries like France, where Aedes albopictus establishment can lead to autochthonous dengue cases and clusters. Enhanced surveillance is crucial, urging the consideration of dengue as a potential diagnosis in travelers with febrile rash, even prior to lab confirmation. Immediate isolation of patients is essential to prevent autochthonous transmission, reduce outbreak risks, and avert public health crises.