Blisters can be caused by chemical or physical injury. An example of chemical injury would be an allergic reaction. Physical injury can be caused by heat, frostbite, or friction.
Blisters typically develop when there is friction and irritation to the surface layer of the skin that cause it to separate from the second layer. Fluid fills in the space between these two layers. Blisters most often appear on the soles of the feet and palms of the hands. The hands and feet often rub against shoes, socks, or sports and music equipment and create friction under moist, warm conditions perfect for blisters
Certain autoimmune diseases feature extensive blistering as one of their symptoms. These include pemphigus and pemphigoid. Blistering also occurs as part of foodborne illness with Vibrio vulnificus (seafood).
Unless infection occurs, blisters usually heal quickly without much additional treatment. If a blister is punctured, it forms an open wound, which should be disinfected and bandaged. Loose bandaging should be used since a bandage that is too tight can result in rupture or rubbing against the blister, causing discomfort. If the blister is broken, the excess skin should not be removed (unless it is dirty or torn). Removing the excess skin often makes the wound heal any infection quickly - if immediately disinfected. Signs of infection include pus draining from the blister, very red or warm skin around the blister, and red streaks leading away from the blister.
Small unbroken blisters that do not cause discomfort can be left alone to heal, because the best protection against infection is a blister’s own skin
