Coxsackievirus A6 associated hand, foot and mouth disease in adults: Clinical presentation and review of the literature

•CVA6 (coxsackievirus A6) has been linked to several worldwide outbreaks since 2008.•This series demonstrates that there is a wide array of disease presentation of CVA6 associated HFMD in adults.•qRT-PCR is the diagnostic test of choice for CVA6, as commercial serologic assays against CVA6 are not available.•CVA6 may be associated with peri-oral involvement, desquamation of the palms and soles, and onchyomadesis.

BackgroundHand, foot, and mouth disease (HFMD) is generally considered a rare illness in adults. Classically, HFMD has been strongly associated with coxsackievirus strain A16 and enterovirus 71. The coxsackievirus A6 (CVA6) strain has been linked to severe worldwide outbreaks since 2008. CVA6 is associated with a more severe and profound course of disease, affecting both children and adults.ObjectivesTo present a series of five adult patients diagnosed with HFMD due to CVA6. We investigate method of diagnosis and compare clinical presentation of adult cases to those in children.Study designEach patient underwent a full-body skin exam as well as inspection of the oral cavity. Rapid plasma reagin (RPR) and serologic assays by complement fixation against coxsackievirus B (1-6) and A (2,4,7,9,10,16) were performed as indicated. As standard serological testing does not detect CVA6, real-time reverse transcription-polymerase chain reaction (qRT-PCR) of serum, buccal swabs, and skin scrapings were performed by the Centers for Disease Control and Prevention (CDC).ResultsEach patient had clinical findings consistent with various stages of HFMD. One patient presented with delayed onychomadesis and desquamation of the palms and soles. RPR and serologic assays by complement fixation against CVB (1-6) and CVA (2,4,7,9,10,16) were mostly negative, although elevated in two patients due to cross-reactivity. qRT-PCR identified CVA6 genetic material in samples from all patients.ConclusionThis series demonstrates that there is a wide array of disease presentation of CVA6 associated HFMD in adults.