Basically, it can be said that blisters are caused by the interaction of friction, heat and moisture.
Friction can come from shoes that are too tight or too big, socks that don't fit properly and from too much stress on the skin, for example on the hands when playing tennis or on the feet when running. You may also be genetically more prone to blisters than others.
Our skin consists of several layers: Upper skin (epidermis), dermis (corium/dermis) and lower skin (subcutis). If our skin is exposed to prolonged pressure or friction, the epidermis separates from the other skin layers. A hollow space is created between them, in which tissue fluid forms: A blister develops.
The blister goes through a five-part cycle of healing.