What would cause a red itchy rash on top of foot above toes looks like sunburn, itchy, slightly tender occurred after onset of third day of period?

Allergy: You could have shoe allergy. See your dermatologist for treatment and evaluation to get the correct diagnosis and treatment.

I dont think the: Period has anything to do with it. Looks like a sunburn ? Any chance it actually is one? From your description simple possibility = rash, worst case = infection. Either way see the foot doc who will know immediately when seeing it. You can try warm compresses and a topical steroid but if no improvement see the doctor.