Nails are a specialized kind of skin that reacts similarly to skin in several ways. Nails will thicken when they are under strain, much like skin will form a corn or callus when there is pressure on it. Our toenails will touch the top and end of our shoes, putting pressure on them and causing minor damage. The toenails will thicken as a result of the strain. Many sportsmen, such as runners, soccer players, and tennis players, notice their toenails thickening for the same reason.
Trauma affects toenails as well. Consider how many times you’ve stubbed your toe, dropped something on it, or had someone tread on it. Each time this happens, the toenail is traumatized, which can contribute to continued toenail thickening. This thickening can happen whether or not a fungal infection is present.
