Conclusion: Factors increasing the risk of severe HFMD include stunting malnutrition (OR = 1.84 - 95% CI: 1.05 to 3.22); not be exclusively breastfed for the first 6 months (OR = 2.03 - 95% CI: 1.08 to 3.84); Low maternal education (OR = 2.77 - 95% CI: 1.06 to 7.28); poor maternal care for patients (OR = 3.93 - 95% CI: 2.40 to 6.44); peak temperature ≥ 39oC (OR = 3.63 95% CI -: 1.91 to 6.90); No signs of oral ulcers (OR = 2.45 95% CI -: 1.28 to 4.69); Startling history (OR = 9.93 95% CI -: 4.89 to 20.14); increase of leukocytosis ≥ 11.0 (K / µl) (OR = 2.52 95% CI -: 1.36 to 4.69); EV71-infected patients (OR = 2.46 95% CI -: 1.29 to 4.69).