Itching

by **James** » Mon Mar 21, 2005 4:53 pm

Why do we itch? Itching appears to be quite random... :shock:

by **mith** » Mon Mar 21, 2005 5:02 pm

Lol, I think it has to do with nerve tissue being irritated.

by **Poison** » Mon Mar 21, 2005 5:42 pm

As much as I know, It is a form of pain.

by **mith** » Mon Mar 21, 2005 7:49 pm

Oh, great, you made the google ads display ugly fotos of discolored skin

by **2810712** » Tue Mar 22, 2005 9:37 am

pain? ? ?
How can be itching a form of pain , I think it's due to nerve irritation , this is more likely ans.

hrushikesh

by **Chris4** » Tue Mar 22, 2005 11:46 am

No i dont think it is a form of pain. I should know this. i have eczema. :cry:

Used to be really bad. itching all the time. its under control now.
Its random for everyone else, but i can itch all the time because my immune system is crazy. overactive i think and i have allergies to dust mites (amongst other things). So you itch due to an irritation on your skin, or sometimes i seem to itch due to an irritation beneath.
Perhaps one reason is because you have something on the surface of your skin that it is irritating you and you itch (or scratch) to get rid of it.
I'll do more research tonight.

by **Chris4** » Tue Mar 22, 2005 8:46 pm

Just did a bit of research:
From http://www.science.edu.sg/ssc/detailed. ... t=4&cat=48

"Itch is an uncomfortable sensation caused by irritation of particular nerve endings in the skin. Nerve fibers have special endings that are tiny organs able to receive messages. Some nerve endings receive pressure sensations, some receive temperature, and some receive pain. Stimulation of pain nerves in the skin sometimes results in itching.

Itching is a symptom and not a disease. Most commonly it is a symptom of skin diseases. Many different causes may produce itching. A common cause is some chemical that touches the skin and irritates it. An allergy may release chemicals that make the skin swell and itch."

Also this is interesting:

The general medical term for itching is pruritus (proor EYE tuss). There are all kinds of pruritus; the kind we're talking about here is called punctate pruritus, spot itching not triggered by any obvious skin disease or other cause.

The operation of the nerve endings in the skin is not clearly understood, but itching appears to be associated with the sense of pain, since persons who can no longer feel pain, for whatever reason, usually don't itch anymore either. In this respect itching is analogous to tickling, which is thought to be related to the sense of pressure.

There are numerous "itch points" scattered about the surface of the body where it's possible to induce itching simply by touching with a fine metal wire. Other areas on the skin usually are relatively insensitive. Itch points appear to be associated with concentrations of fine free nerve endings.

It's known that in some cases the nervous system has different mechanisms for conducting sensory impressions of varying intensity, such as light and firm pressure, and there is speculation that itching may be a watered-down sense of pain, designed to detect extremely faint stimuli. Thus if you have dry skin or a stretched hair follicle or some minor localized chemical imbalance, the nerves may multiply it into the sharp irritation that you instinctively scratch.

From: http://www.straightdope.com/classics/a1_090.html
The website above also answered my question of why i sometimes twitch when i start to fall asleep.

If you want more info theres more here: http://science.howstuffworks.com/question600.htm

Well. i guess that answers the question. It seems as if poison was partly correct.

by **James** » Tue Mar 22, 2005 10:36 pm

Wow, great research, thanx

by **biostudent84** » Wed Mar 23, 2005 7:14 am

Poison wrote:As much as I know, It is a form of pain.

You are right, as is Chris4. Itching, while not as unpleasant as what we usually think of in regards to "pain," it is still a form of pain. The particular nerve endings Chris4 spoke of are called nocireceptors, and are the same nerves that relay the sensation of pain. There are four other types of "--receptor" nerves as listed below:

Thermoreceptors--two kinds, one to detect warmth, one to detect cold
Chemoreceptors--on your tounge...three kinds, used to detect sweet, sour, and bitter
Mechanoreceptors--used to detect pressure...they are also in your ear and detect minute differences in air pressure, allowing us to hear sound
Photoreceptors--in your eye...used to detect light

by **Poison** » Wed Mar 23, 2005 1:38 pm

A few days after being hurt (cut or something like that) it starts itching. Isn't it? I think this can be a good proof of that itching is a form of pain.

by **Chris4** » Wed Mar 23, 2005 2:12 pm

Poison wrote:A few days after being hurt (cut or something like that) it starts itching. Isn't it? I think this can be a good proof of that itching is a form of pain.

I've personally never experienced this. But then i have eczema so I can't say.
This doesnt sound like a good biological system because you need the wound to heal. not scratch it open again, because its itching :shock:

by **James** » Wed Mar 23, 2005 3:47 pm

I've personally never experienced this. But then i have eczema so I can't say.
This doesnt sound like a good biological system because you need the wound to heal. not scratch it open again, because its itching

It would appear not, perhaps the itching promotes blood flow to the area for quicker healing :?:

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