Chafing refers to a continuous rubbing of the skin that causes redness or soreness. It often results from situations in which the skin is moist and rubs together. This can occur while walking, running, bicycling or performing other activities. Areas prone to chafing include the thighs, groin, underarms, nipples and buttocks.

Chafing occurs when the skin becomes irritated by the friction caused by rubbing – either against other skin or against a foreign material (e.g., shirt, shoes). As the friction occurs, the top layers of skin can be rubbed away, exposing the raw and more sensitive skin below. Chafing often results in a stinging or burning sensation at the point of irritation.

Moisture and sweat can cause the amount of friction and chafing to increase. If sweat is allowed to dry on the skin, the salt crystals left behind can cause even more friction, increasing the amount of damage and abrasion to skin cells.

When chafing occurs in load-bearing areas, blisters can form. A blister results when several layers of skin are pulled or separated from the skin below. The result is a sac-like protrusion of skin that contains liquid. Blisters are usually sensitive and painful.

Once chafing has occurred, the area should be washed with soap and cool-to-lukewarm water. An antiseptic solution should be applied to the site before it is covered with a sterile gauze pad that allows the wound to breathe.

Conditions associated with chafing include:

• Epidermolysis bullosa. A group of disorders in which skin blisters form as a response to minor trauma, including chafing. Blisters tend to appear when there is rubbing in pressure-bearing areas, such as the palms of the hands and the soles of the feet.
  
  
• Intertrigo. A red, painful rash that occurs in areas where the skin rubs together in warm and moist conditions. Such areas include the groin, abdominal folds, under the arms and under the breasts. Skin can crack and bleed in severe cases.
  
  
• Jogger's nipples. Common condition caused by friction that occurs between a shirt or bra and the nipples while running. The constant chafing over the course of the run often leaves the nipples with painful crusted lesions that may bleed. The condition affects both men and women.