Blisters are small liquid-filled sacs, which develop when the upper layer of skin rubs against a static surface, like the inside of a shoe, and tears away from the layers beneath.
“This is often as a result of trainers rubbing against sensitive parts of the feet, especially if worn over a long period of time,” says podiatrist Dina Gohil of DG Podiatrist.
Blisters often occur on the heels, the balls of the feet, between the toes or on the tips of the toes. They are more likely to happen in wet conditions, or if feet swell and begin rubbing against the insides of a shoe or on the seams. An ill-fitting shoe or one wearing out on the inside can also cause blisters. There are a myriad of things that can lead to blisters including thin or abrasive socks and a piece of dirt stuck inside a shoe.