• Chinese traditional/simplified: 水泡,水泡 (shuǐ pào)
• Czech: puchýř
• Danish: vable, blære
• Finnish: rakkula
• German: Blase
• Greek: φουσκάλα (fuskála)
• Polish: pęcherz
• Russian: волдырь (voldýr’)

• Chinese traditional/simplified: 氣泡,气泡 (qì pào)
• German: Blase
• Greek: φουσκάλα (fuskála)
• Russian: пузырь (puzýr')

• Chinese traditional/simplified: 起水泡,起水泡 (qǐ shuǐ pào)
• Danish: hæve sig i vabler

• Danish: kritisere skarpt

Derived terms

• blistery
• blood blister

A blister is a small pocket of fluid within the upper layers of the skin. Blisters can be filled with blood (known as blood blisters) or with pus (if they become infected). However, most blisters are filled with a clear fluid called serum. Serum is the part of the blood that remains after red blood cells and clotting agents have been removed.

A blister usually forms because the outer layer of the skin has become damaged. Fluid collects under the damaged layer of skin, cushioning the tissue underneath, protecting it from further damage and allowing it to heal.

A blood-blister usually forms when a small blood vessel close to the surface of the skin ruptures (breaks) and blood leaks into a tear between the layers of skin. This can happen if the skin is crushed, pinched or squeezed very tightly.

Blisters can also form as the result of certain medical conditions.

Cause

Blisters are usually caused by injury to the skin from heat or from friction, which create a tear between the epidermis—the upper layer of the skin—and the layers beneath. When this happens, the surface of the skin remains intact, but is pushed outwards as serum seeps into the newly created space between the layers.

Short periods of intense rubbing can cause a blister, but any rubbing of the skin at all can cause a blister if it is continued for long enough. Blisters are most common on the hands and feet, as these extremities are susceptible while walking, running, or performing repetitive motions. Blisters form more easily on moist skin than on dry or soaked skin, and are more common in warm conditions.

Sometimes, the skin can blister when it comes into contact with a cosmetic, detergent, solvent or other chemical; this is known as contact dermatitis. Blisters can also develop as a result of an allergic reaction to an insect bite or sting.

There are also a number of medical conditions that cause blisters. The most common are chickenpox, herpes, impetigo, and a form of eczema called dyshidrosis. Other, much rarer conditions that cause blisters include:

• Bullous pemphigoid – a skin disease that causes large, tightly-filled blisters to develop, usually affecting people over the age of 60.
• Pemphigus – a serious skin disease in which blisters develop if pressure is applied to the skin; the blisters burst easily, leaving raw areas that can become infected.
• Dermatitis herpetiformis – a skin disease that causes intensely itchy blisters, usually on the elbows, knees, back and buttocks. The blisters usually develop in patches of the same shape and size on both sides of the body.
• Chronic bullous dermatosis – a disease that causes clusters of blisters on the face, mouth or genitals.

Prevention

Blisters on the feet can be prevented by wearing comfortable, well-fitting shoes and clean socks. Blisters are more likely to develop on skin that is moist, so moisture-absorbing socks or frequent sock changes will aid those with particularly sweaty feet. While exercising or playing sports, special sports socks can help keep feet drier and reduce the chance of blisters.

Before going for a long walk, it is important to ensure that shoes have been broken in. If a hot area on the foot is felt, taping padding over the affected area can prevent the formation of a blister.

To avoid blisters on the hands, gloves should be worn when using tools such as a shovel or pickaxe, doing manual work such as gardening, and handling detergents, cleaning products, solvents and other chemicals.

A lubricant, typically talcum powder, can be used to reduce friction between skin and apparel. People put talcum powder inside gloves or shoes for this purpose.

Sunscreen and sun protection should also be used during the hottest part of the day to avoid blisters from sunburn, and moisturizing, after-sun or calamine lotions can help to ease discomfort in the case of burns.

Treatment

Most blisters heal naturally and do not require medical attention. As new skin grows beneath the blister, the fluid contained within it will be slowly reabsorbed by your body and the skin on top will dry and peel off.

The unbroken skin over a blister provides a natural barrier to infection. This means that you should try to keep blisters intact and unbroken in order to avoid infection. Try not to pierce a blister with a needle, but allow it to break on its own once the skin underneath has healed. If the blister is in a place (such as a hand or foot) that makes it extra painful, follow these steps: 1. Wash your hands and the blister with soap and water, and sterilize the blister with rubbing alcohol. 2. Sterilize a pin with rubbing alcohol. 3. Make small pinpricks on the edge of the blister and drain the fluid through these. 4. Cover the blister with first-aid ointment and a sterile bandage.

Cover small blisters with an adhesive dressing. Larger blisters should be covered with a gauze pad or dressing that you can then tape in place. If you have a blister in a position that is causing you pain or that makes it likely to burst (such as on the sole of your foot), its important to cover it with a soft dressing to pad and protect it. Then change the dressing daily.

If a blister bursts, don't peel off the dead skin on top of the blister. Gently press the area to get rid of all the fluid inside, and then cover the blister and the area around it with a dry, sterile dressing to protect it from infection until it heals.

Blood blisters should also be left to heal naturally. As with other blisters, if a blood blister bursts it is important to keep the area clean and dry, and protect it with a sterile dressing to prevent infection.

Blood blisters are often painful, and you may wish to apply an ice pack to the area immediately after the injury that caused it. You should apply the ice pack for between 10 and 30 minutes. The ice should not touch your skin directly as this may cause a cold burn, so place a towel over the injured part first.

Even when popped as described above, a blister can become infected, Staph aureus infections being most common. Blisters that have become infected can be treated with antibiotics prescribed by your GP. Blisters caused by a medical condition are treated by treating the underlying condition.

A common treatment utilized by medics in the U.S. Army is to drain the fluid from a blister and to inject the same amount of compound tincture of benzoin, to help seal the space created by the blister, to serve as a local antiseptic, and to prevent further abrasion or loss of skin.

See also

• Buboe
• Dracunculiasis
• Herpangina
• Herpes zoster
• Ulcer

References

External links

abscess, air bubble, aposteme, assail, attack, balloon, bed sore, bilge, birthmark, blackhead, bladder, blain, blaze, bleb, blemish, blob, blood blister, boil, boss, bow, brand, bubble, bubo, bulb, bulge, bulla, bump, bunch, bunion, burl, burn, burn in, burn off, button, cahot, canker, canker sore, carbuncle, cast, castigate, cauterize, chancre, chancroid, char, check, chilblain, chine, cicatrix, clump, coal, cold sore, comedo, condyle, convex, crack, crater, craze, cupel, defacement, defect, deformation, deformity, disfiguration, disfigurement, distortion, dowel, ear, eschar, excoriate, fault, felon, fester, festering, fever blister, fistula, flame, flange, flap, flaw, flay, found, freckle, furuncle, furunculus, fustigate, gall, gathering, globule, gnarl, gumboil, handle, hemangioma, hemorrhoids, hickey, hill, hump, hunch, jog, joggle, keloid, kibe, kink, knob, knot, knur, knurl, lash, lentigo, lesion, lip, loop, lump, milium, mole, mountain, needle scar, nevus, nub, nubbin, nubble, oxidate, oxidize, papilloma, papula, papule, parch, paronychia, parulis, peg, petechia, piles, pimple, pit, pock, pockmark, polyp, port-wine mark, port-wine stain, pustule, pyrolyze, rib, ridge, rift, ring, rising, roast, scab, scar, scarify, scathe, scorch, scourge, scratch, sear, sebaceous cyst, shoulder, singe, skin alive, slash, soap bubble, soft chancre, solder, sore, spine, split, stigma, strawberry mark, stud, sty, style, suppuration, swelling, swinge, tab, torrefy, track, trounce, tubercle, tubercule, twist, ulcer, ulceration, verruca, vesicate, vesicle, vulcanize, wale, warp, wart, weal, weld, welt, wen, wheal, whelk, whitehead, whitlow, wound