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Related to skin: Skin diseases, Skin rashes


the outer covering of the body. The skin is the largest organ of the body, and it performs a number of vital functions. It serves as a protective barrier against microorganisms. It helps shield the delicate, sensitive tissues underneath from mechanical and other injuries. It acts as an insulator against heat and cold, and helps eliminate body wastes in the form of perspiration. It guards against excessive exposure to the ultraviolet rays of the sun by producing a protective pigmentation, and it helps produce the body's supply of vitamin D. Its sense receptors enable the body to feel pain, cold, heat, touch, and pressure. The skin consists of two main parts: an outer layer, the epidermis, and an inner layer, the corium (or dermis).

Epidermis. The epidermis is thinner than the corium, and is made up of several layers of different kinds of cells. The number of cells varies in different parts of the body; the greatest number is in the palms of the hands and soles of the feet, where the skin is thickest.

The cells in the outer or horny layer of the epidermis are constantly being shed and replaced by new cells from its bottom layers in the lower epidermis. The cells of the protective, horny layer are nonliving and require no supply of blood for nourishment. As long as the horny outer layer remains intact, microorganisms cannot enter.
Corium. Underneath the epidermis is the thicker part of the skin, the corium, or dermis, which is made up of connective tissue that contains blood vessels and nerves. It projects into the epidermis in ridges called papillae of the corium. The nerves that extend through the corium end in the papillae. The various skin sensations, such as touch, pain, pressure, heat, and cold, are felt through these nerves. The reaction to heat and cold causes the expansion and contraction of the blood capillaries of the corium. This in turn causes more or less blood to flow through the skin, resulting in greater or smaller loss of body heat (see temperature).

The sweat glands are situated deep in the corium. They collect fluid containing water, salt, and waste products from the blood and carry it away in canals that end in pores on the skin surface, where it is deposited as sweat. Perspiration helps regulate body temperature as well, because cooling of the skin occurs when sweat evaporates. The sebaceous glands are also in the corium. They secrete the oil that keeps the skin surface lubricated.

Beneath the corium is a layer of subcutaneous tissue. This tissue helps insulate the body against heat and cold, and cushions it against shock.

The hair and nails are outgrowths of the skin. The roots of the hair lie in follicles, or pockets of epidermal cells situated in the corium. Hair grows from the roots, but the hair cells die while still in the follicles, and the closely packed remains that are pushed upward form the hair shaft that is seen on the surface of the skin.

The nails grow in much the same way as the hair. The nail bed, like the hair root, is situated in the corium. The pink color of the nails is due to their translucent quality which allows the blood capillaries of the corium to show through.
Normal skin. From Frazier et al., 2000.
skin test application of a substance to the skin, or intradermal injection of a substance, to permit observation of the body's reaction to it. Such a test detects a person's sensitivity to such allergens as dust and pollen, or to preparations of microorganisms believed to be the cause of a disorder.

There are several types of skin tests, including the patch test, the scratch test, and the intradermal test.
Patch Test. This is the simplest type of skin test. A small piece of gauze or filter paper is impregnated with a minute quantity of the substance to be tested and is applied to the skin, usually on the forearm. After a certain length of time the patch is removed and the reaction observed. If there is no reaction, the test result is said to be negative; if the skin is reddened or swollen, the result is positive.

The patch test is used most often in testing for skin allergies, especially contact dermatitis.
Scratch Test. In this test, one or more small scratches or superficial cuts are made in the skin, and a minute amount of the substance to be tested is inserted in the scratches and allowed to remain there for a short time. If no reaction has occurred after 30 minutes, the substance is removed and the test is considered negative. If there is redness or swelling at the scratch sites, the test is considered positive.

The scratch test is often used in testing for allergies. A complete screening for allergic sensitivity may require numerous skin tests. Only an extremely minute quantity of the substance can be used in each test since severe allergic reactions can occur.

The scratch test is also used in the diagnosis of tuberculosis. In Pirquet's reaction, for example, tuberculin is used, and the local inflammatory reaction that results is more marked in tuberculous persons than in normal ones.
Intradermal Tests. In these tests, the substance under study is injected between the layers of skin. Intradermal tests are used for diagnosis of infectious diseases and determination of susceptibility to a disease or sensitivity to an allergen.

In the intradermal test for tuberculosis, the Mantoux test, a purified protein derivative (PPD), prepared from tubercle bacilli, is injected. In a positive result, the area becomes reddened or inflamed within 72 hours. This indicates past or present infection with or exposure to the tubercle bacillus. An infection that has been present for at least 2 to 8 weeks will usually be revealed by the test.

The Schick test is used to determine susceptibility to diphtheria. A very small dose of diphtheria antitoxin is injected into the forearm. In a positive reaction the area becomes red and remains so for about a week. If no reaction occurs, the person is immune to the disease.

The trichophytin test is sometimes used in diagnosing suspected cases of superficial fungus infection of the skin, such as ringworm. In the presence of infection by the fungus Trichophyton, an injection of trichophytin, which is prepared from cultures of the fungus, will produce a reaction similar to the tuberculin reaction. Skin tests, of course, are always made in an area separate from the infected area.

In addition to their frequent use in testing for allergies, intradermal tests are employed in the diagnosis of parasitic infections, such as schistosomiasis, other fungus diseases besides trichophytosis, and mumps.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(skin), [TA]
The membranous protective covering of the body, consisting of the epidermis and dermis (corium).
Synonym(s): cutis [TA]
[A.S. scinn]
Farlex Partner Medical Dictionary © Farlex 2012


The membranous tissue forming the external covering or integument of an animal and consisting in vertebrates of the epidermis and dermis.
v. skinned, skinning, skins
To bruise, cut, or injure the skin or surface of: She skinned her knee.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Vox populi adjective Cutaneous noun Anatomy Cutis The outer integument of the body which consists of epidermis and dermis, the latter of which rests on subcutaneous tissue. See Aging skin, Artificial skin, Blue skin, Cigarette-paper skin, Composite cultured skin, Diamond skin, Elephant skin, Glossy skin, Harlequin skin, Hide-bound skin, Leopard skin, Lizard skin, Moleskin, Moroccan leather skin, Paper money skin, Red skin, Sandpaper skin, Second Skin®, Spray-on skin, Swiss cheese skin, Washerwoman skin.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


(skin) [TA]
The membranous protective covering of the body, consisting of the epidermis and corium (dermis).
Synonym(s): cutis [TA] .
[A.S. scinn]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


Enlarge picture
The organ that forms the outer surface of the body. It shields the body against infection, dehydration, and temperature changes; provides sensory information about the environment; manufactures vitamin D; and excretes salts and small amounts of urea.

Skin consists of two major divisions: the epidermis and the dermis. Depending on its location and local function, skin varies in terms of its thickness, strength, presence of hair, nails, or glands, pigmentation, vascularity, nerve supply, and keratinization. Skin may be classified as thin and hairy or thick and hairless (glabrous). Thin hairy skin covers most of the body. Glabrous skin covers the surface of the palms of the hands, soles of the feet, and flexor surfaces of the digits. See: illustration; hair for illus; burn; dermatitis; dermis; eczema; epidermis; rash

alligator skin

Severe scaling of the skin with formation of thick plates resembling the hide of an alligator. See: ichthyosis

artificial skin

Human skin equivalent.

bronzed skin

Brownish hyperpigmentation of the skin, seen in Addison's disease and hemochromatosis, some cases of diabetes mellitus, and cirrhosis.

deciduous skin


elastic skin

Ehlers-Danlos syndrome.

foreign bodies in the skin

Objects that enter the skin accidentally or are inserted deliberately. The areas involved are cleaned carefully. Foreign material can be removed carefully piece by piece or by vigorous swabbing with gauze or a brush and a soapy solution. A sterile dressing should be used.

For removal of a small foreign body, the area is cleaned first with mild soap and warm water. A clean needle can be sterilized by heating it to a dull or bright red in a flame; this can be done with a single match. Because both ends of the needle get hot, it is wise to hold the far end in a nonconductor such as a fold of paper or a cork. The needle is allowed to cool. A black deposit on its surface should be disregarded; it is sterile carbon and does not interfere with the procedure. The needle is introduced at right angles to the direction of the sliver, and the sliver is lifted out. Most people attempt to stick the needle in the direction of the foreign body and consequently thrust many times before they manage to lift the sliver out. When the sliver is removed, an antiseptic is applied and the wound covered with a sterile dressing. Tetanus antitoxin or a tetanus booster may be required, depending on the history of immunization.

glabrous skin

Skin that does not contain hair follicles, such as that over the palms and soles.

glossy skin

Shiny appearance of the skin due to atrophy or injury to nerves.

hidebound skin


loose skin

Hypertrophy of the skin.

parchment skin

Atrophy of the skin with stretching.

photoaged skin

Skin changes caused by chronic sun exposure. This condition is prevented by avoiding suntanning and sunburning and has been treated with topical tretinoin and chemical peels.
Synonym: photodamaged skin

photodamaged skin

Photoaged skin.

piebald skin


scarf skin

The cuticle, epidermis; the outer layer of the skin.

sun-damaged skin

Photoaged skin.

tissue-engineered skin

Human skin equivalent.

true skin

Medical Dictionary, © 2009 Farlex and Partners


The body's outer covering. The skin is a major organ, of area 5–6 m2. It is self-regenerating, self-lubricating and self-repairing and provides heat regulation. It is sensitive to touch, pressure, pain and temperature. It protects against solar radiation and bacterial infection and synthesizes vitamin D. The lower layer, the true skin (corium) is living, the outer layer (epidermis) has an external layer of dead, flattened horny cells.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
Fig. 285 Skin. A section of the human skin showing the for a larger image
Fig. 285 Skin . A section of the human skin showing the dermis.


an organ that forms the outer covering of an animal that is external to the main musculature, often bearing scales, hair or feathers. Skin is the most widespread organ of the body and consists of an EPIDERMIS derived from the embryonic ECTODERM, and a DERMIS originating from a MESODERMIS. The epidermis is often hardened and covered by a cuticle, but may be only one cell thick.

The subcutaneous fat of the dermis acts as insulation and reduces heat loss. Heat is also conserved by the skin in cold conditions by contraction of the superficial blood vessels which diverts blood to lower layers of the skin. In some structures, such as the ear, special shunt vessels occur which dilate in cold conditions and pass blood directly from arterioles to venules, thus bypassing the superficial capillaries to reduce heat loss.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005


(skin) [TA]
Membranous protective body covering, consisting of epidermis and dermis (corium).
Synonym(s): cutis [TA] .
[A.S. scinn ]
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about skin

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..

Q. anyone knows how to stop hard skin on the feet from becoming cracked??? during summer my feet got lots of hard skin and in the heel area the skin actually got cracked kinda deep. it hurts now and the cracks are starting to get infected I guess... do u guys know how to solve this?? I know there are some creams for that but I thought maybe now it's too late for that and I need something stronger?

A. There are good creams for moisterizing the skin of your feet on a daily basis, however now that you feel they might be infected you should see a dermatologist for some better treatment.

Q. How can you know if a mole is a skin cancer or not? I'm only 15, but I’ve had this small thing on my right shoulder for a reeeeaaaally long time. It's the same color as my skin. It’s smaller than the head of a pencil eraser, perfectly round, and its smooth. I've never worried about it seriously, until about a week ago, when I read an article in a magazine about skin cancer. Even then I wouldn't have worried about it, because It didn't really match any of the symptoms, except one. It did bleed once about 2 1/2 years ago. And it said bleeding was a big sign I don't know, what do you think? And please try and say something other than," go have it checked out". Because I currently have no insurance. Thanks :]

A. If I’m not mistaken- there are clinics that do free checkups for skin cancer. I know that in my town there are couple. Here is a link I got when I googled “do free checks for skin cancer”:
look for one near your home.

More discussions about skin
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References in periodicals archive ?
A deficiency in vitamin A can result in flaky, dry skin.
Cetaphil Philippines brand manager Francesca Sy said that the National Healthy Skin Mission fulfills the brand's purpose of improving the lives of Filipinos through maintenance of healthy skin.
There are many ways to apply yogurt to your skin. You can gently rub a plain of yogurt on your skin and leave it for some minutes before washing off it with lukewarm water.
Skin cancer is not common among people with darker skin.
The controlled energy delivered onto the skin avoids overheating, making it an ideal treatment for fine lines, sagging skin and wrinkles, acne, large pores, and more.
A'Keeping yourself well-hydrated is key for skin health, but unfortunately drinking more water does not equate to better-hydrated skin,' says Sophie.
Naturally, moisturizers are already considered as effective anti-agers because it keeps skin nourished and hydrated.
Skin biopsies having inadequate material, benign lesions or showing equivocal diagnosis of malignancy were excluded from the study.
An infant experiences the first major exposure to microbes at birth, and the types of bacteria present on the newborn's skin varies by delivery mode.
Once done, all that's required is for the skin cells of this layer to proceed to divide and relocate upward to fill whatever space remains.
Showers are recommended compared to taking a long bath because they expose the skin to less water, which then prevents the top layer from losing all of its natural oils.