Baking soda is a dehydrating agent. It sucks up moisture. Chemically speaking, it is forcefully taking out and removing water from the moist skin of athlete’s foot and from the wound. This moisture removal process is felt as a burning sensation.
Baking soda applied on crotch itch will burn like hell. That is because the baking soda is sucking out the moisture from the moist skin where the tinea corporis resides. Both the tinea pedis and the tinea corporis require moisture to survive. This sucking process or moisture removal process is felt as a burning sensation.
With hydrogen peroxide, the extra oxygen atom wants to combine with the hydrogen in the moisture of the skin infected by the athlete’s foot fungus tinea pedis. Since the athlete’s foot infection is an open wound, the nerves are raw, and the raw nerves give us the athlete’s foot itch. When hydrogen peroxide is applied, the extra oxygen combines with the hydrogen in the moist skin of the athlete’s foot infection, causing the moisture to break down into hydrogen and oxygen atoms. This hydrogen removal process caused by the extra oxygen atom in the peroxide creates the burning sensation. The release of the extra oxygen atom also kills the tinea pedis. The foaming indicates that the extra oxygen atoms serve as a poison gas that kills the tinea pedis.
That is why athlete’s foot itches. When soaked in hydrogen peroxide, the athlete’s foot itches, burns and dries out afterwards, leaving a white residue on the skin consisting of dead corpses of tinea pedis.
When we feel a burning sensation, we are actually feeling “fire: the state, the process or an instance of combustion in which ignited fuel or other material combines with oxygen,…” [The Random House College Dictionary]. In other words, we are feeling “combustion: rapid oxidation, slow oxidation not accompanied by high temperature and light.” [Ibid]