Friction Blisters

Updated: Apr 06, 2023
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
  • Print
Overview

Practice Essentials

Friction blisters of the skin commonly occur in active populations. They are the result of frictional forces between the involved skin area and the object with which the skin is in contact. Friction blisters create localized discomfort; however, they should not be taken lightly because secondary impetigo may become a serious complication with resulting cellulitis and sepsis. [1]

The bulk of research on friction blisters comes from the military because of the nature of the physical activity involved in this field. Friction blisters have also received much attention in the field of sports medicine.

See the image below.

Friction blisters on human foot. Courtesy of Andry Friction blisters on human foot. Courtesy of Andry French (own work), via Wikimedia Commons.

Signs and symptoms

Discrete bullae formation at sites of trauma is evident, as seen in the image above.

Friction blisters tend to occur in areas of thick adherent stratum corneum (eg, palms, soles, heels, dorsa of fingers). In regions of the body where the stratum corneum is thinner, a repeated friction force causes the stratum corneum to erode, and instead of a blister, an erosion or abrasion occurs. Children often present with poorly fitting shoes and reporting a blister on the heel.

The likelihood of forming a friction blister at susceptible sites is based on the magnitude of the frictional force and the number of times an object moves across the skin (ie, shear cycles). Moisture and lubricating substances present on the skin surface are additional factors. With a greater frictional force, fewer cycles of rubbing against the skin are needed to produce a blister. Hand blisters are an occupational hazard in major league baseball pitchers. [2]

Moisture on the skin surface may either increase the friction force or, in the case of very moist skin, decrease it temporarily by providing lubrication. Lubricating agents also tend to reduce the friction force temporarily at the onset; however, friction tends to increase with prolonged application of the external force.

Pyogenic granuloma on the hand has been described subsequent to a friction blister in a hand surgeon. [3]

Erythema and superficial blisters, a friction-induced injury referred to as pool toes, may be evident on the plantar surface of the toes or on the heels in contact with a rough pool surface. [4]

Impetigo may become a serious complication, with resulting cellulitis and sepsis.

Diagnostics

The friction blister forms with a split in the stratum spinosum. Midepidermal necrosis is evident. The blister roof consists of normal and necrotic keratinocytes; the blister floor consists of normal, edematous, and degenerating keratinocytes. The blister cavity is filled with a clear transudate. High mitotic activity is present in the base of the blister about 30 hours after formation of the friction blister. A significant inflammatory infiltrate is not observed as long as the blister site is not secondarily infected.

Management

Also see Prevention.

Management of friction blisters includes sterile drainage of the site while leaving the blister roof intact to serve as a dressing. This method helps relieve some discomfort and protects the site from superinfection. A donut of moleskin may also be applied to minimize additional trauma to the blister and to relieve discomfort. [5]  If the blister roof is already fully or partially removed, treat the site as an open wound with appropriate antiseptic and surgical bandage application. Hydrocolloid dressings have also been proven to decrease discomfort and encourage healing. Some recommend debridement of the skin of the blister, the use of a topical containing nitrofurazone, and the application of a bandage. [6]

Optimal therapy for blisters after prolonged walking is unclear. [7]  A study compared 2 different regimens, wide area fixation dressing versus adhesive tape, evaluating 907 participants in Holland (aged 45 ±16 years, 52% men) who received 4131 blister treatments. [7]  Owing to diminished effectiveness and satisfaction, use of wide area fixation dressing was not favored over adhesive tape for routine first-aid treatment for friction blisters.

Prompt attention to friction blisters is important to prevent the development of secondary impetigo with possible cellulitis and sepsis. Institute appropriate systemic antibiotic therapy if impetigo develops. Use of povidone-iodine solution (Betadine) may be beneficial. [8]

Next:

Pathophysiology

The influence of epidermal hydration on the friction of human skin against textiles was studied. Increasing cutaneous hydration may cause sex-specific changes in the mechanical properties and/or surface topography of human skin, leading to skin softening and increased real contact area and adhesion. [9]

Studies involving rubbing the skin with a constant force show an initial slight exfoliation of the skin over the involved area. Focally, mild erythema also develops. The patient may experience stinging or burning, while a zone of pallor develops around the erythematous area. The pallor eventually extends into the region of erythema and this area develops into a blister.

The effect of wearing socks with different frictional properties on plantar shear was studied because this is a possible mechanical risk factor for foot lesion development. [10] Wearing socks with low friction against the foot skin reduced the plantar shear force on the skin more than a sock with low friction against the insole.

Friction blister formation is affected by epidermal hydration. In a study of 11 men and 11 women, the friction between the inner forearm and a hospital fabric was measured in different hydration states. [11] Increasing skin hydration caused sex-specific changes in the mechanical properties and/or surface topography, as the friction of female skin demonstrated significantly higher moisture sensitivity.

Technology such as thermographic images may facilitate assessment of traumatically damaged foot skin. [12]

Previous
Next:

Etiology

Poorly fitting shoes are the most common cause. Heat, sweating, and maceration of the skin may predispose to friction blister formation. A study of foot blister formation in 3 groups of 11 participants showed biomechanical interactions on the plantar surface of individuals prone to blisters to be at variance from less predisposed to this finding. [13] Wearing wet socks was found to enhance the risk of foot blisters in hikers. [14] Baseball pitchers suffer repeated trauma between the baseball seams and the fingers of the pitching hand, most often at the tips of the index and long fingers. [2]  An unusual case of a climbing harness causing a flank friction blister has been reported. [15]

Previous
Next:

Epidemiology

During the first Iraqi War, the prevalence of foot friction blisters among American troops was 33%, of which 11% required medical care. [16]

No known predilection is reported for any particular race.

No known predilection is described for either sex. Women aged 26-34 years who are unable to break in their boots and have a past history of blisters, were the most likely to develop friction blisters among American troops during the first Iraqi War. [16]

No known predilection is apparent for any age group.

Previous
Next:

Prognosis

Friction blisters create localized discomfort; however, they should not be taken lightly because secondary impetigo may become a serious complication with resulting cellulitis and sepsis.

Previous
Next:

Patient Education

Educate patients about the importance of prevention measures (see Prevention).

Previous