Chik Sign... and Hyperpigmentation

Diffuse Hyperpigmentation Can Distinguish Chikungunya From Other Arbovirus Infections

By Scott Baltic

November 05, 2019

NEW YORK (Reuters Health) - With outbreaks of chikungunya fever (CF) having been reported in previously untouched regions from southern Europe to the Americas, clinicians need to be aware of even such relatively rare signs of the infection as acquired diffuse hyperpigmentation, researchers say.

In a case report online October 16 in JAMA Dermatology, they describe 12 infants in India with CF-related diffuse hyperpigmentation seen during monsoon season.

The chikungunya virus is spread by Aedes aegypti and Aedes albopictus mosquitos and is endemic in Africa, the Indian subcontinent and Southeast Asia. Recently, however, climate change and increased human travel have helped spread CF to Italy and France and to Latin America, the Caribbean and the U.S. Gulf Coast.

The infants in the new series (ages nine days to 11 months) were seen at a single tertiary-care center in Chandigarh, in the monsoon months of 2016 and during an epidemic of chikungunya in northern India that year, Dr. Keshavamurthy Vinay of the Postgraduate Institute of Medical Education and Research told Reuters Health by email.

All 12 presented with sudden-onset, rapidly progressing diffuse hyperpigmentation all over the body, which followed a febrile maculopapular eruption by three to eight days. Each diagnosis of CF was confirmed by IgM testing.

"Chik sign," a brown-black pigmentation of the tip of the nose was common, as was similar pigmentation (without background erythema) of the ear pinnae, flexural areas and perioral region.

Pigmentation was progressive during hospitalization in half of the patients, but improved in all patients within six months.

Dr. Peter Hotez, dean of the National School of Tropical Medicine, Baylor College of Medicine, in Houston, Texas, told Reuters Health by phone that in recent years there has been a big increase in cases involving arboviruses, such as chikungunya, dengue and Zika in the United States, specifically along the Gulf Coast.

Not all of the reasons for this spread are understood, he said, but he suggested that urbanization (the mosquitos in question are urban species) is probably a factor and that poverty and climate change could also be involved.

Dr. Hotez called the study "important for pediatricians in the U.S., especially on the Gulf Coast."

Clinically, he explained, it can be very difficult to distinguish between the arboviruses, because they all tend to present with fever and rash. When present, hyperpigmentation would help single out chikungunya.

Longer term, chikungunya and other arboviruses "will be a big thing down here on the Gulf Coast," and possibly beyond, warned Dr. Hotez, who's also a spokesperson for the Infectious Diseases Society of America.

SOURCE: https://bit.ly/2qr6GOu

JAMA Dermatol 2019.