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a vesicle, especially a bulla.
blood blister a vesicle having bloody contents, as may be caused by a pinch or bruise.
fever b's herpes febrilis.
water blister one with clear watery contents.


1. A fluid-filled, thin-walled structure under the epidermis or within the epidermis (subepidermal or intradermal).
2. To form a blister with heat or some other vesiculating agent.


/blis·ter/ (blis´ter) a vesicle, especially a bulla.
blood blister  a vesicle having bloody contents, as may be caused by a pinch or bruise.
fever blister  see herpes simplex.
water blister  one with clear watery contents.


a. A local swelling of the skin that contains watery fluid and is caused by burning or irritation.
b. A similar swelling on a plant.
v. blis·tered, blis·tering, blis·ters
To cause a blister to form on.
To break out in or as if in blisters.

blis′ter·y adj.


a vesicle or bulla of the skin, containing watery matter or serum.


A saccular skin vesicle filled with serous fluid, which separates the epidermis and/or dermis, and which may be linked to shearing forces caused by trauma, burn, or a vesicatory agent; a collection of serous fluid.


 A skin vesicle filled with serous fluid, caused by burns, trauma, or by a vesicatory; a collection of serous fluid


1. A fluid-filled thin-walled structure under the epidermis or within the epidermis (subepidermal or intradermal).
2. To form a blister with heat or some other vesiculating agent.


1. A collection of fluid below or within the epidermis.
2. To form a blister.


The area should be cleansed with mild soap and a protective dressing applied. Unless a blister is painful or interferes with function because of its size, it should not be punctured. If puncturing is required, it should be done aseptically, with the skin left in place. A sterile pressure bandage should then be applied.


If infection develops, treatment is the same as for any other wound, including tetanus prophylaxis or booster as required.
Enlarge picture
BLOOD BLISTER: On the sole of the foot after cryotherapy for a plantar wart

blood blister

A small subcutaneous or intracutaneous extravasation of blood resulting from the rupture of blood vessels. See: illustration


A firm dressing should be applied with moderate pressure to prevent extravasation and hasten absorption of blood. In some cases it is desirable to puncture the wound aseptically and aspirate the contents.

calendar blister

A blister pack in which each dose of a medication is labeled with a specific day of the week (e.g., M, T, W) or of the month (1st, 2nd, 3rd) to encourage and assist with daily compliance with medication dosing.

fever blister

A vesicular rash usually appearing on the lips or mucous membrane of the mouth during another infectious illness. The rash is caused by herpes simplex virus.
See: cold sore

fly blister

A blister produced by application of cantharides to the skin.

friction blister

An inflamed blister that forms beneath the epidermis after vigorous or repeated rubbing of the skin, e.g., on the toes or heels during sports activities.


A fluid-filled swelling occurring within or just under the skin, usually as a result of heat injury or unaccustomed friction. The fluid is serum from the blood and is usually sterile.


a collection of fluid, usually serum, between the layers of the skin, causing an elevated lesion. Caused by friction, burns, local allergic responses, e.g. stings. Blisters are common with poor footwear or when exercise is of high intensity and long duration.


fluid-filled dermoepidermal junction or epidermal vesicle (Table 1 and Box 1)
  • acantholytic blister intraepidermal blister; heals without scarring

  • blood blister a traumatic blood-filled blister; skin haematoma

  • junctional blister dermoepidermal junctional blister; heals with scarring

Table 1: Causes of blisters in the feet
Intermittent/constant pressure at skin surfaceFrom an underlying bony prominence, tight shoes, sock seam, grit/sand at skin surface
Friction/shear stressTight shoes, loose shoes, excess sweating, foot oedema, unaccustomed exercise
Biomechanical anomaliesGeneralized hypermobility, Haglund's deformity, excess subtalar joint pronation
Foot deformityHallux abductovagus, lesser-toe deformities
Chemical irritationHypersensitivity reaction to applied chemicals, e.g. used in shoe manufacture/leather tanning, applied caustics, plaster mass
Thermal damageBurns, sunburn, chilling, perniosis, cryotherapy, radiation
Infectionse.g. impetigo, fungal/tinea infections
Genetic traite.g. epidermolysis bullosa
Autoimmune diseasee.g. pemphigus, pemphigoid
Idiopathice.g. spontaneous blistering in response to minimal stimulation in some patients with diabetes
Box 1: Treatment of blisters
  • Identify/eradicate (where possible) immediate cause of blister

  • Leave blister intact, unless extremely tense/painful (contained fluid protects underlying sensitized tissues)

  • Paint area with weak iodine solution (unless patient is iodine-sensitive) and/or compound tincture of benzoin

  • Strap over lesion/reduce surface friction with two-way extension strapping, fleece or Compeed

  • Pad as necessary to reduce exciting stress

  • Review in 3-7 days as necessary


A fluid-filled, thin-walled structure under the epidermis or within the epidermis (subepidermal or intradermal).


n See vesicle or bulla.


1. a vesicle, especially a bulla, a lesion of the skin.
2. a paste containing an irritant such as cantharides used to plaster onto a horse's leg to produce counterirritation and encourage healing of a strained tendon or ligament.

blister beetle
blood blister
a vesicle having bloody contents, as may be caused by a pinch or bruise.
blister fly
internal blister

Patient discussion about blister

Q. What's the best treatment for a blister?

A. use a clean needle and poke a small hole right at the base, between normal skin and the blister. Push the blister down, allow it to drain completely and put a bandaid over it; don't ever rip off blister skin allow it to fall off or reattach naturally.

Q. What are the causes of viral blisters on the skin? For a few months now I've been having these hard viral blisters on my fingers. The only way to get rid of them is with freezed carbon. It does go away with that treatment- after a few weeks but then a new one appears. How can I prevent it from "attacking" again??

A. These viral blisters you are describing are caused by HPV (papilloma virus), and are very hard to get rid of without treatment with freezed carbon. Many of us have the virus but not everyone gets the actual infection. There is not a proved way of preventing from it to happen again after treatment, unfortunately..

More discussions about blister
References in periodicals archive ?
A bacterial infection of the blisters can also occur.
If you blister easily, the third key is to apply tape before beginning your hike.
The blister line will complement the full suite of highly flexible and state of the art commercial packaging equipment already installed in the new Audubon facility.
If your feet are moving inside your dance shoes, you are courting blisters.
Passed blisters are picked by vacuum from the transport conveyor and loaded into transport cartridges, which are presented by an operator in a replication of the loading carousel.
Just pick the blister beetle off the plant and drop in the can.
Moreover, the present corona beam technology can detect anomalies in the material, such as contamination, blisters, bubbles, un-catalyzed or unblended resin, low density material (e.
We have written numerous articles in the Post about lysine preventing fever blisters for those who had chronic outbreaks.
Other causes of air entrapment leading to bubbles or blisters include inadequate venting and gas traveling across the part surface during the filling or packing stage.
After being "triggered," the herpes simplex virus begins to reproduce, resulting in damage to skin cells that can lead to the characteristic blisters.
The blisters crust over and fall off after 7 to 10 days.
The incidence of foot blisters was 21% for the antiperspirant group and 48% for the placebo group.