blister

/blis"teuhr/, n.

1. a thin vesicle on the skin, containing watery matter or serum, as from a burn or other injury.

2. any similar swelling, as an air bubble in a coat of paint.

3. a relatively large bubble occurring in glass during blowing.

4. Mil. a transparent bulge or dome on the fuselage of an airplane, usually for mounting a gun.

5. Photog. a bubble of air formed where the emulsion has separated from the base of a film, as because of defective processing.

6. a dome or skylight on a building.

7. the moving bubble in a spirit level.

8. a small blisterlike covering of plastic, usually affixed to a piece of cardboard and containing a small item, as a pen, bolt, or medicinal tablet.

v.t.

9. to raise a blister or blisters on: These new shoes blistered my feet.

10. to criticize or rebuke severely: The boss blistered his assistant in front of the whole office.

11. to beat or thrash; punish severely.

v.i.

12. to form or rise as a blister or blisters; become blistered.

[1250-1300; ME blister, blester < ON blaestri, dat. of blastr swelling. See BLAST, BLOW²]

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Rounded skin elevation in which fluid fills a separation between layers of epidermis or between the epidermis and the dermis.

The fluid is usually clear; yellowish fluid contains pus, and red fluid contains blood. Blisters often occur on the palms or soles when pressure and friction cause an upper skin layer to move back and forth over the one under it. A small gap opens between them and becomes filled with fluid. This type generally heals spontaneously, sometimes leaving a thickened callus. Blisters that occur as symptoms of contact dermatitis, viral infection, or autoimmune disease can appear anywhere on the body and may leave scars.

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▪ dermatology

      a rounded elevation of the skin containing clear fluid, caused by a separation either between layers of the epidermis or between the epidermis and the dermis. Blisters are classified as vesicles if they are 0.5 cm (0.2 inch) or less in diameter and as bullae if they are larger. Blisters can commonly result from pressure and friction on sites such as the palms or soles; they are produced when friction causes an upper skin layer to move back and forth over an underlying skin layer. A small gap opens up between them and becomes filled with fluid. Blisters may also occur as symptoms of contact dermatitis, viral infection, or an autoimmune disease, in which case they can appear anywhere on the body.

      Blistering usually takes place within the uppermost layer of the skin (epidermis), producing fragile, easily broken blisters; subepidermal blisters are tenser and are more difficult to break. In either case, the blister fluid is usually clear and colourless; yellowish fluid is a sign that it contains pus and red that it contains blood. Friction blisters generally heal spontaneously, sometimes leaving a thickened callus; disease blisters may leave scars, particularly when they are located deep in the epidermis.

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