New strain of hand, foot and mouth virus worries parents, pediatricians

Bernard Cohen, M.D., director of pediatric dermatology at Johns Hopkins Children's Center, and colleague Kate Puttgen, M.D., have seen or consulted on close to 50 such cases in the last few months and have received countless phone calls from scared parents and concerned physicians. Cohen believes this number may be just the tip of the iceberg with primary care pediatricians seeing the bulk of new cases.

Cohen and Puttgen want to reassure parents that most cases of the disease are benign and that nearly all patients recover in seven to 10 days without treatment and without serious complications.

"What we are seeing is relatively common viral illness called hand-foot-and-mouth disease but with a new twist," Cohen says.

The culprit is an unusual strain of the common coxsackie virus that usually causes the disease. The new strain, coxsackie A6, previously found only in Africa and Asia, is now cropping up all over the United States.

The coxsackie virus strikes infants and children under age 5 in the summer and autumn months. Symptoms include fever and malaise and, a day or two later, a non-itchy skin rash with flat or raised red spots on the hands and feet and/or mouth sores. The new strain, however, behaves somewhat differently from its homegrown cousin, Cohen says. It carries a slightly higher risk for more serious illness and more widespread rash that can involve the arms, legs, face and diaper area. The new strain also seems to affect older as well as younger children.

"We've talked with many of our pediatric dermatology colleagues around the country and the number of cases and the severity of the rash is clearly new and different from the typical hand, foot and mouth disease we are used to seeing," adds Puttgen. "The good news is that it looks bad but hasn't actually caused severe symptoms for our patients."

The new virus can also cause a rash that mimics lesions of herpes simplex virus, which requires treatment with antivirals.

"It can look like disseminated herpes simplex, and parents may panic if they don't know what it is," Cohen says. "But unlike herpes simplex, this rash evolves very fast. It's bad for a few days and then gets better very quickly without any treatment at all."

To reduce the spread of the virus, Cohen and Puttgen advise frequent hand washing and good general hygiene. Pediatricians need not refer patients to a specialist if they recognize the rash for what it is and if the child is otherwise healthy, they say. "If the child has low-grade fever, but is otherwise well, waiting and watching is appropriate," Cohen says. "If the child is having problems with feeding or drinking or acting ill, it's time to call the doctor." Specifically, Cohen says, children with immune deficiencies, cancer or other serious illness should be followed closely by their pediatrician to avoid or promptly treat any complications.