The results of the multivariable logistic regression analysis indicated that rare onset age, vomiting, location of skin lesion, NLR, and serum albumin levels were factors associated with severe GI involvement [rare onset age: odds ratio (OR) 2.561 (95% CI, 1.202–5.495; p = 0.015); vomiting: OR 2.273 (95% CI, 1.558–3.317; p = 0.000); purpura above the waist: OR 1.479 (95% CI, 1.029–2.125; p = 0.034); NLR ≥ 3.27: OR 2.267 (95% CI, 1.578–3.258; p = 0.000); and ALB ≤ 38.25 g/L: OR 3.592 (95% CI, 2.450–5.267; p = 0.000)] (Table 3, Figure 1). Here, ALB is linked to purpura.