When to consider a Zika diagnosis
Experts clarify data, offer perspectives on assessing, managing potential patients
At last count, numbers of U.S. travel-related and home-grown Zika cases was continuing to rise. With rash being among the primary symptoms of this often asymptomatic illness, dermatologists are among the providers who might encounter these patients and should consider Zika as a possible diagnosis.
As of August 17, 2016, the CDC reported there were 14 locally acquired mosquito-borne Zika cases in the U.S.; 2,245 travel-associated cases; and one laboratory-acquired case. A small area of Miami, Fla., had documented five symptomatic and eight asymptomatic locally acquired Zika infections and, on a global scale, more than 60 countries or territories have reported new local Zika transmission, according to a viewpoint published August 8 in JAMA.1
Zika spreads rapidly, according to Jose Dario Martinez, M.D., who practices internal medicine and dermatology in Monterrey, Nuevo Leon, Mexico.
“The Zika threat is bigger than dengue and chikungunya to the U.S., … because it can be transmitted in several ways, and Zika virus is more difficult to detect because most cases are asymptomatic, and suddenly you face the complications, such as Guillain-Barre, and, in unaware pregnant women, microcephaly,” says Dr. Martinez, an international fellow of the American Academy of Dermatology, who presented on Zika, dengue and chikungunya at AAD’s summer sessions earlier this year. “Cutaneous manifestations include an erythematous maculopapular rash that affects [the] trunk, extremities and the genitalia. Other features include non-purulent conjunctivitis, small joints arthralgia and low grade fever. Mucocutaneous affection include mouth enanthem and small purpuric lesions in soft palate.”
Zika fever, an emerging viral disease in The Americas, is transmitted mainly by the Aedes aegypti female mosquito. Zika virus is transmitted also from mother to fetus during the first trimester of pregnancy, by sexual intercourse or blood transfusion.
The incubation period is one week, according to Dr. Martinez.
What makes Zika difficult to diagnose is that more than 80% of patients are asymptomatic, according to Dr. Martinez.
There are important similarities and differences among Zika, dengue and chikungunya viruses, according to Dr. Martinez. Zika, dengue and chikungunya are transmitted by the same vector, occur in the same geographic area of the world, and clinically all three have in common rash, fever and joint pain. Unlike dengue, Zika does not have hemorrhagic manifestations, shock syndrome or high fever. And unlike chikungunya, in Zika there is no severe arthritis, periocular melanosis (depend on the skin color of the patient) and no vesicles or bullae in the genitalia area, Dr. Martinez says.
Zika complications include Guillain-Barre syndrome and microcephaly in newborns from mothers infected during the first trimester, according to Collin M. Blattner, D.O., dermatology resident, Silver Falls Dermatology and Allergy, Salem, Ore., and author of an article on Zika, published June 2016 in the Journal of the American Academy of Dermatology.2
New research3 suggests that while Zika is thought of as a transient infection in adults, without marked long-term effects, exposure to the virus might, in fact, have consequences on the adult brain. In the mouse model, the researchers show that certain adult brain cells, including those that replace lost or damaged neurons throughout adulthood and could be critical for learning and memory, may be vulnerable to infection.