Ah, blisters... we've all had them, whether it was part-way through the school sponsored walk or because you were a bit clumsy that time you tried to take your apple crumble out of the oven. Maybe even when you had chickenpox as a child, or perhaps you over-indulged out on the beach. Bloody things... sometimes literally.

Formation

Any one of those situations up there can cause a blister, and plenty of other situations beside. There's friction, where all you need for a blister to form is some sort of injury to the skin which creates a split between the upper layer of skin (the epidermis) and those beneath. Short periods of intense rubbing, or gentle rubbing over a longer period will do, and it's especially easy if the skin is moist and soft. It's easy to see why blisters are common on the hands and feet, and often occur when walking or running. And there you go: the damage is done, and blood serum seeps into the space between the two layers, pushing out the surface of the skin. Perhaps, if you've been particularly rough, a small blood vessel near the damaged layer will rupture, and instead of clear, transparent serum you'll get a small bubble of blood, often known as a blood blister.

Contact dermatitis is the blistering of skin from some form of irritant, perhaps detergent, solvent or some other corrosive chemical. The formation is the same - damaged skin leads to a swelling of serum. Similarly, the damage caused by a sudden application of heat may lead to a blister, or some form of disease - I mentioned chickenpox earlier, and you can add herpes, impetigo and a number of other skin disorders to that list. Of course, if you are blistering unexpectedly, what are you doing sitting round searching for 'blistered penis' in Google? I agree, the internet is a great source of information, but it's no substitute for medical help.

Treatment

Many people dig out the needles as soon as a blister appears, occasionally passing it through a flame before using it to break open the beautifully sealed natural barrier of skin which is currently protecting the damaged layer beneath. Don't do it - an unbroken blister will heal beautifully on its own in the majority of cases, and will quite happily break open on its own once the skin beneath has healed, allowing the dead layer of epidermis to flake off on its own. It's hardly glamorous, I realise, but at least you won't end up with an infected blister and a course of antibiotics.

Prevention

Soft sweaty feet, rough socks and a pair of new shoes... ack - hang on, no! Scrub that clearly bad advice and instead get yourself a pair of well-fitting shoes, clean and dry socks, and perhaps some talc to keep your feet dry and lubricated. When breaking in new shoes, don't be afraid to put a sticking plaster or some sort of spongy padding over areas that feel uncomfortable.

Wear gloves when gardening, and perhaps some more talcum powder. Shovel or pickaxe handles look beautifully smooth, but their constant rubbing is slowly working away to produce blisters on those soft, sensitive areas of your hands.

Going out on a hot summer's day? Don't forget that golden piece of advice... you're just as free to wear sunscreen as everyone else.

Oh, and oven gloves? They're what's for dinner...

Blis"ter (?), n. [OE.; akin to OD. bluyster, fr. the same root as blast, bladder, blow. See Blow to eject wind.]

1.

A vesicle of the skin, containing watery matter or serum, whether occasioned by a burn or other injury, or by a vesicatory; a collection of serous fluid causing a bladderlike elevation of the cuticle.

And painful blisters swelled my tender hands.
Grainger.

2.

Any elevation made by the separation of the film or skin, as on plants; or by the swelling of the substance at the surface, as on steel.

3.

A vesicatory; a plaster of Spanish flies, or other matter, applied to raise a blister.

Dunglison.

Blister beetle, a beetle used to raise blisters, esp. the Lytta (or Cantharis) vesicatoria, called Cantharis or Spanish fly by druggists. See Cantharis. -- Blister fly, a blister beetle. -- Blister plaster, a plaster designed to raise a blister; -- usually made of Spanish flies. -- Blister steel, crude steel formed from wrought iron by cementation; -- so called because of its blistered surface. Called also blistered steel. -- Blood blister. See under Blood.

© Webster 1913.

Blis"ter, v. i. [imp. & p. p. Blistered (#); p. pr. & vb. n. Blistering.]

To be affected with a blister or blisters; to have a blister form on.

Let my tongue blister.
Shak.

© Webster 1913.

Blis"ter, v. t.

1.

To raise a blister or blisters upon.

My hands were blistered.
Franklin.

2.

To give pain to, or to injure, as if by a blister.

This tyrant, whose sole name blisters our tongue.
Shak.

© Webster 1913.