itchy bumps only on calf muscles

mamaB • Two girls 💕 pregnant with girl #3 due May 30th 2022 💓

hey mamas! was wondering if any of you would know what this is? its little rised itchy bumps that she always scratches but they are only on her calf muscles, nowhere else! I was thinking maybe a heat rash ? 🤔 she is 20 months old btw !