A friction blister is a fluid-filled sac that forms within the upper layers of the skin, typically caused by repeated rubbing and heat generated between the heel and footwear. This mechanical stress causes the layers of the epidermis to separate, filling the gap with plasma-like fluid. Blisters on the heel are particularly painful because constant pressure makes the skin unstable and prone to rupture. Preventing blisters requires understanding both immediate measures and the underlying causes of friction.
Immediate Prevention Strategies: Creating Friction Barriers
Applying specialized materials directly to the heel creates a protective layer that absorbs shear forces. A simple method involves using rigid athletic or medical tape applied smoothly to the entire heel area contacting the shoe. The tape acts as a second skin, allowing the shoe to rub against the tape’s surface instead of the skin. For optimal adherence, the skin must be clean and dry before application.
Another common friction barrier is moleskin, a thick, cotton-flannel material with an adhesive backing. To use it preventatively, cut a piece slightly larger than the anticipated friction area and apply it directly to the skin. If a tender “hot spot” has developed, cut a donut-shaped hole in the center of the pad and place it around the spot, not on it. This technique elevates the surrounding skin and redirects pressure away from the irritated point.
Hydrocolloid dressings, often sold as blister pads, can be applied pre-emptively to high-risk areas, offering a thick cushion that reduces friction and shear. For temporary, short-term activity, a thin layer of petroleum jelly or an anti-chafing stick reduces the friction coefficient. These lubricants minimize resistance between the skin and sock, but they wear off quickly and are not a substitute for durable taping or padding.
Addressing the Root Causes: Shoe Fit and Moisture Control
The primary cause of heel blisters is a mismatch between the foot and the footwear, which generates excessive movement and friction. When purchasing shoes, try them on later in the day when feet are naturally at their largest to ensure adequate space. A well-fitting shoe should secure the heel firmly within the heel counter, preventing the vertical slip that leads to rubbing.
Sock material plays a large role in managing moisture, which softens the skin and makes it more susceptible to damage. Avoid cotton socks because they absorb sweat and hold moisture against the skin. Instead, choose synthetic fabrics like polyester or acrylic, or natural materials like wool, as these fibers wick moisture away.
Wearing a thin, moisture-wicking liner sock beneath a thicker outer sock manages moisture and distributes friction between the two layers. For individuals with excessive foot perspiration, applying an antiperspirant or foot powder directly to the foot reduces moisture levels before activity. New shoes should be broken in gradually over several short wearing sessions, allowing the heel counter material to soften and conform to the foot’s shape.
First Aid for Formed Blisters
If a blister has already formed, the best approach is to leave it intact, as the skin “roof” provides a natural, sterile barrier against infection. Small, non-painful blisters should be covered with a simple protective dressing or a specialized hydrocolloid bandage to shield them from further friction. The fluid inside will be reabsorbed by the body within a few days, and the underlying skin will heal.
Draining a blister is advised only if it is large, extremely painful, or impedes walking. To drain safely, first wash the area and hands thoroughly with soap and water, then sterilize a sharp needle with rubbing alcohol. Puncture the blister carefully at several spots near the edge, allowing the fluid to drain while leaving the skin roof intact.
After draining, apply an antiseptic ointment and cover the area with a non-stick sterile dressing or gauze pad. The area must be monitored for signs of infection, including increasing redness, swelling, warmth, pus, or foul-smelling discharge. If these signs appear, or if red streaks radiate away from the blister, seek professional medical attention immediately.