Correspondence

We read with great interest the case report by Høgsberg & Bygum (1) of atypical hand, foot and mouth (HFM) disease caused by echovirus 3; however, we do not share their conclusion. The finding of an enterovirus, such as echovirus 3, in stools can be incidental. Indeed, enteroviruses can be excreted in stools for 10 weeks or more after an infection (2). Therefore the finding of an enterovirus in stools is not sufficiently specific to draw a definitive conclusion of causality in HFM. This is even more the case if the enterovirus isolated is not considered a usual pathogen associated with HFM. The virus is present in skin vesicle fluid (3), therefore the most specific virological test in HFM is the sampling of the contents of skin vesicles using enterovirus PCR to confirm the causal link.

We appreciate the comment from Del Giudice & Hubiche. We share the point that the detection of echovirus 3 may be purely incidental. However, the patient presented a clinical picture compatible with atypical hand, foot, and mouth disease, and no other differential diagnoses fitted appropriately. A skin swab was negative for herpesvirus, varicella zoster virus, enterovirus and pathogenic bacteria. Echovirus 3 was detected in stool. The finding of echovirus 3 has been reported previously in a patient with hand, foot, and mouth associated onychomadesis (4), but could also be seen in controls. We must conclude that we found a temporal relationship of echovirus 3 and atypical hand, foot, and mouth disease, but cannot prove a causal relationship.