Clinical and Etiological Characteristics of Atypical Hand-Foot-and-Mouth Disease in Children from Chongqing, China: A Retrospective Study

Abstract

Background: Hand-foot-and-mouth disease (HFMD) is a disease that had similar manifestations to chickenpox, impetigo, and measles, which is easy to misdiagnose and subsequently causes delayed therapy and subsequent epidemic. To date, no study has been conducted to report the clinical and epidemiological characteristics of atypical HFMD.

Methods: 64 children with atypical HFMD out of 887 HFMD children were recruited, stool was collected, and viral VP1 was detected.

Results: The atypical HFMD accounted for 7.2% of total HFMD in the same period (64/887) and there were two peaks in its prevalence in nonepidemic seasons. Ten children (15.6%) had manifestations of neurologic involvement, of whom 4 (6.3%) were diagnosed with severe HFMD and 1 with critically severe HFMD, but all recovered smoothly. Onychomadesis and desquamation were found in 14 patients (21.9%) and 15 patients (23.4%), respectively. The most common pathogen was coxsackievirus A6 (CV-A6) which accounted for 67.2%, followed by nontypable enterovirus (26.6%), enterovirus 71 (EV-A71) (4.7%), and coxsackievirus A16 (A16) (1.5%).

Conclusions: Atypical HFMD has seasonal prevalence. The manifestations of neurologic involvement in atypical HFMD are mild and usually have a good prognosis. CV-A6 is a major pathogen causing atypical HFMD, but not a major pathogen in Chongqing, China.

Figure 1

Proportion of atypical HFMD to total HFMD per month and number of total HFMD in each month. Black: proportion of atypical HFMD; white: number of total HFMD. X-axis: time; left Y-axis: proportion of atypical HFMD; right Y-axis: number of total HFMD.

Figure 2

Characteristics of rashes in atypical HFMD. (a) A boy aged 1 year, and papulae were mainly distributed on the perioral area and face; (b) a boy aged 1 year and 1 month, and papulae/vesicles were found at the back; (c) a girl aged 1 year and 6 months, and papulae were found on the hand; (d) a boy aged 1 year and 8 months, and erosions were noted in both feet.

Figure 3

Incidences of onychomadesis and desquamation in atypical HFMD children at different time points. X-axis: time of follow-up after acute phase; Y-axis: proportion of children with onychomadesis/desquamation in children receiving follow-up. Statistical analysis was performed with SPSS version 17.0 (SPSS Inc., Chicago, IL, USA). A value of P < 0.05 was considered statistically significant.

Figure 4

Phylogenetic analysis of coxsackievirus A6 strains based on the partial VP1 gene sequence (nucleotide position: 254–864). ■: virus separated in the present study, and remaining viruses were from Genbank including 2011 Spain strains (JX845228, JX845232, KC431247, and KC431252), 2000–2011 Japan strains (AB114096, AB234336, AB234337, AB234338, AB649286, AB649287, AB649288, AB649289, and AB649291), 2010 Finland strains (HE572902, HE572930, and HE572939), and 2009–2011 Taiwan strains (JN582001, JQ946051, and JQ946054).