Pediatric Dermatology: Hand-Foot-Mouth and Beyond

Ilona Frieden, MD

Sheila Freidlander, MD

Dr Frieden discusses the new manifestations of an old disease. Classic HFMD presents with exanthem (skin) and (enanthem) mouth symptoms. Skin symptoms include grey-white vesicles on the palms and soles and occasionally  on the buttocks, diaper area, knees and elbows. Mouth symptoms include vesicles and erosions on anterior oral mucosa and are very painful.

From November of 2010 to February 2011, 63 cases of atypical HFMD were reported to the CDC. 34 cases had vesicle, stool, blood, and/or respiratory samples. 74 percent of these cases were PCR positive for coxsackie A6, whereas in the past in North American most cases were due to coxsackie A16.  These patients differ from those with classic HFMD in that there was a wider age range, greater than ten percent of the body surface area was involved, these patients had fevers and a rash that appeared “severe”, and they had findings of “locus minoris resistentiae.”

Mathes E and colleagues published a report on coxsackie exanthems characterizing the 2011 outbreak of the emerging viral type, A6. There were 64 children and 18 and ot 19 were positive for PCR enterovirus. 58 percent of the children had atopic dermatitis, 56 percent had ecema herpeticum-like eruptions which were termed “eczema coxsackium”.  Additionally 22 percent had findings of locus minoris, 35 perecent had Gianotti-Crosti-like eruptions and 18 percent had hemorrhagic purpuric or petechial skin lesions. (Mathes E, et al. Pediatrics. 2013;132(1):e149-157.) This virus can also affect adults.  An important sequellae is  onychomadesis which can develop two to four weeks after infection.

New Ways to Diagnose Viruses

Traditionally, it was difficult and expensive to find out which/whether a specific virus was pathogen. Viral cultures are expensive and the question remained as to what to look for. Acute and convalescent titers were the “gold standard”, but follow-up studies were required so you didn’t receive the answers you were looking for right away.  Dr Friedlander comments that we are now lucky enough to have commercially available multiplex PCR diagnostic panels for viruses. These panels are available in some labs or hospitals. They can typically detect influenza A and B, adenovirus, parainfluenza 1-3, respiratory syncytial virus A and B, human metapneomovirus and human rhinovirus. Other panels can detect coronavirus, coxsackie/echo virus, bocavirus, adenoviruses, parainfluenza and seasonal influenzas.  This is a positive step as it provides clinicians with the ability to have answers more rapidly than previously.