Chikungunya and Coxsackievirus A6

Chikungunya coming to roost

Chikungunya coming to roost

Chikungunya, a tropical virus, “had never infected anyone in the Western Hemisphere until December 20, 2013," when it appeared in the Caribbean, says Stephen K. Tyring, M.D., Ph.D. Since then, thanks to international travel and the spread of the Aedes aegypti mosquito that carries chikungunya, "This disease has spread extremely rapidly throughout the Caribbean and southern United States," where it has already infected approximately 1 million people total. Dr. Tyring is clinical professor of dermatology, microbiology/molecular genetics, and internal medicine at the University of Texas and director of the Center for Clinical Studies in Houston, Texas.

Skin signs of chikungunya can resemble those of dengue – islands of white in a sea of red rash. "The difference is that only one strain of chikungunya is known to cause problems, whereas dengue has four strains" that do. This means that if a person is infected with chikungunya a second time, says Dr. Tyring, the infection likely will be milder than the first; the opposite is true with dengue, which can lead to dengue hemorrhagic fever. 

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Because both chikungunya and dengue cause skin symptoms, he says, patients with these diseases may present to dermatologists. However, dermatologists more likely will see these illnesses when consulting with primary care physicians who have hospitalized patients due to severe fever and other systemic manifestations. The only ways to tell the two apart for certain include checking serology for antibodies or using polymerase chain reaction (PCR) assays to check for the actual virus, he says.

Patients who present with acute onset of fever, rash, and polyarthralgia should be evaluated for chikungunya, particularly patients who have existing dermatoses such as psoriasis, acne, atopic dermatitis, or tuberculoid leprosy, as these conditions can be exacerbated by chikungunya.

As with dengue, says Dr. Tyring, the only treatment for chikungunya is supportive care, typically with anti-inflammatory agents, pain medications and hydration. "Usually, the acute signs and symptoms (fever, muscle and joint aches) will pass within a week or so. The big problem with chikungunya is the joint problems," which may require a rheumatology referral. Although far less lethal than dengue, chikungunya causes excruciating joint pain that can last from weeks to, rarely, years. "People say it feels like their arms and legs are being pulled out of the socket."

NEXT: Atypical Coxsackie virus

Atypical Coxsackie virus

Closer to home, Drs. Tyring and Friedlander warn of a new wrinkle appearing with the atypical strain of hand, foot and mouth (HFM) disease dermatologists increasingly encounter.¹ In the last two years, says Dr. Tyring, his clinic has seen 20 to 30 adults with HFM disease caused by Coxsackievirus A6 (CVA6). Less common than other strains of Coxsackievirus, this strain seems to make adults sicker than children.

Along with blisters on the palms, soles, mouth, and elsewhere, Dr. Tyring explains, adults get quite systemically ill, with muscle aches and fever whose origins emergency-room personnel cannot identify, so these patients are commonly hospitalized. Dr. Friedlander adds, "Kids may have significant hemorrhagic and blistering lesions, but they usually do quite well."

As with chikungunya and dengue, says Dr. Tyring, "There's no specific treatment. But what's unique about the adults we've seen over the past two years with HFM disease is that, when the signs and symptoms are improving, patients start shedding their toenails and fingernails."

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Sheila Fallon Friedlander, M.D., professor of clinical pediatrics and medicine (dermatology) at the University of California, San Diego, also has seen CVA6-associated onychomadesis in children, appearing three to eight weeks after infection onset. "It's important to warn families about this possibility, and reassure them when it develops."

In some cases, she adds, a patient may present with nail shedding only. When questioned, the mother remembers that the child had an illness that included a rash, fever, and cough one to two months previously. Similarly, "Sometimes the parents develop onychomadesis as their only presenting symptom." The only way to determine absolutely if patients have the A6 strain, says Dr. Tyring, is sending swabs from deep buccal mucosa to the Centers for Disease Control & Prevention.

Drs. Friedlander and Tyring report no relevant financial interests. This article was assembled from presentations at MauiDerm, January 26-30, 2015 and supplemental interviews.

NEXT: REFERENCES 

References

1.     Downing C, Ramirez-fort MK, Doan HQ, et al. Coxsackievirus A6 associated hand, foot and mouth disease in adults: clinical presentation and review of the literature. J Clin Virol. 2014;60(4):381-6.

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