Can you use cortisone cream on a (almost) 2 year old?

My daughter turns 2 in 11 days & has a severe case of hand foot mouth. Her feet are very itchy & she’s not sleeping because her feet itch. She’s waking up every 5-10 minutes to scratch her feet vigorously.

I’ve tried Benadryl to help with not only the itching but her sleep. But it doesn’t really seem to do a whole lot.

Can I put some cortisone cream on her feet to see if that helps??