EXPERT ANALYSIS FROM THE AAD SUMMER ACADEMY 2016
BOSTON (FRONTLINE MEDICAL NEWS) – Maintain clinical suspicion for dengue fever among individuals with recent travel to endemic areas who present with a rash and other signs and symptoms of infection, an expert advised at the American Academy of Dermatology summer meeting.
Dengue fever accounts for nearly 10% of skin rashes among individuals returning from endemic areas, and related illness can range from mild to fatal, said Jose Dario Martinez, MD, chief of the Internal Medicine Clinic at University Hospital “J.E. Gonzalez,” UANL Monterrey, Mexico.
“This is the most prevalent arthropod-borne virus in the world at this time, and it is a resurgent disease in some countries, like Mexico, Brazil, and Columbia,” he noted.
Worldwide, more than 2.5 billion people are at risk of dengue infection, and between 50 million and 100 million cases occur each year, while about 250,000 to 500,000 cases of dengue hemorrhagic fever occur each year, and about 25,000 related deaths occur.
The last dengue outbreak in the United States was in Texas in 2005, where 25 cases occurred, but in Mexico, 18,000 new cases occurred in 2015, Dr. Martinez said.
Of the RNA virus serotypes 1-4, type 1 (DENV1) is the most common, and DENV2 and 3 are the most severe, but up to 40% of cases are asymptomatic, he noted, adding that the virus has an incubation period of 2-8 days. When symptoms occur, they are representative of acute febrile illness, and may include headache, high fever, myalgia, arthralgia, retro-orbital pain, and fatigue. A faint, itchy, macular rash commonly occurs at 2-6 days into the illness. According to the World Health Organization, a probable dengue fever case includes acute febrile illness and at least two of either headache, retro-orbital pain, myalgia, arthralgia, rash, hemorrhagic manifestations, leukopenia, or supportive serology.
“Sometimes the nose bleeds, the gums bleed, and there is bruising in the patient,” Dr. Martinez said. “Most important are retro-orbital pain and hemorrhagic manifestations, but also supportive serology.”
About 1% of patients progress to dengue hemorrhagic fever or dengue shock syndrome during the critical phase (days 4-7) of illness. This is most likely in those with serotypes 2 and 3, but can occur with all serotypes. Warning signs of such severe disease include abdominal pain or tenderness, persistent vomiting, pleural effusion or ascites, and of particular importance – mucosal bleeding, Dr. Martinez said.
By the WHO definition, a diagnosis of dengue hemorrhagic fever requires the presence of fever for at least 2-7 days, hemorrhagic tendencies, thrombocytopenia, and evidence and signs of plasma leakage; dengue shock syndrome requires these, as well as evidence of circulatory failure, such as rapid and weak pulse, narrow pulse pressure, hypotension, and shock.
It is important to maintain clinical suspicion for dengue fever, particularly in anyone who has traveled to an endemic area in the 2 weeks before presentation. Serologic tests are important to detect anti-dengue antibodies. IgG is important, because its presence could suggest recurrent infection and thus the potential for severe disease, Dr. Martinez said. Polymerase chain reaction can be used for detection in the first 4-5 days of infection, and the NS1 rapid test can be positive on the first day, he noted.
The differential diagnosis for dengue fever is broad, and can include chikungunya fever, malaria, leptospirosis, meningococcemia, drug eruption, and Zika fever.
Management of dengue fever includes bed rest, liquids, and mosquito net isolation to prevent re-infection, as more severe disease can occur after re-infection. Acetaminophen can be used for pain relief; aspirin should be avoided due to risk of bleeding, Dr. Martinez said.
Hospitalization and supportive care are required for those with dengue hemorrhagic fever or dengue shock syndrome. Intensive care unit admission may be required.
Of note, a vaccine against dengue fever has shown promise in phase III trials. The vaccine has been approved in Mexico and Brazil, but not yet in the U.S.
Dr Martinez reported having no disclosures.
