A blister is a puffy area often filled with clear fluid that may develop on the topmost layer of the skin. These types of small pockets can be caused by exposure to extreme temperatures, chemicals, or infections, but the most common source tends to be repeated pressure or rubbing that results in a friction blister. Although friction blisters can be painful and prone to infection if not treated properly, they may be prevented by taking measures to add a barrier around the skin in order to lessen friction.
A friction blister develops after repeated pressure or rubbing against an area of skin begins to cause irritation to the top layer of skin. The skin forms a pocket of clear fluid above the skin as a protective mechanism to prevent additional irritation while new skin forms beneath it. As the skin heals, the blister begins to slowly dry out. Early symptoms of friction blisters include pain, puffiness, and redness, until eventually the pocket of clear fluid itself forms.
There are a variety of possible situations that may cause a friction blister to form. These types of blisters tend to develop most often on the feet and hands, two parts of the body that are often the most prone to performing activities involving friction. Improperly fitting shoes are one of the most common causes of friction blisters on the feet, either due to excessive pressure from shoes that are too tight or overly loose shoes that cause the shoe to move repeatedly over the areas of the foot when walking. If the blisters occur on the hands, it is generally the result of gripping an item or repeating a motion numerous times, such as a carpenter or construction worker holding and operating tools. Athletes, such as baseball players or golfers, are also often at a higher risk of friction blisters on the hands from tightly gripping their athletic equipment.
A friction blister will generally heal on its own and not require any treatment if care is taken to prevent additional friction, such as wearing socks and properly fitting shoes for foot blisters, or bandaging or wearing protective gloves over blistered areas when performing activities with the hands. Keeping the blister clean and not draining the fluid may also help it heal, usually within a week. If the blister is pierced to remove the fluid, it may be at a higher risk of becoming infected. Signs of infection include fluid that is green or yellow, itchiness or increased swelling or redness, and fever. Infection will typically require medical attention to prevent further complications.