In response. Yes.
It depends on whether the white stuff under your big toe nail smells or not.
If it smells foul, it is the accumulation of flakes of skin from the invasive activity of tinea pedis.
If it does not smell foul, it is the accumulation of flakes of skin from normal shedding of dead skin cells or the action of tinea corporis. These dead skin cells are white regardless of one’s skin color. They are actually transparent under the microscope, since they are now devoid of pigmentation.
Wash with water if the white stuff does not smell and then pick it out from under the toe nail, or wash with hydrogen peroxide if the white stuff smells and then pick it out from under the toe nail.
After wearing a pair of dark colored socks for a day, one can turn the socks inside out and one can see the white flakes in the inside of the socks. This is the same white stuff that has accumulated under the big toe nail. These white flakes also shed when one rubs one’s bare feet on dark colored bed sheets.