Structure and Functions (Magill’s Medical Guide, Sixth Edition)
The anatomy of the skin consists of two major parts: the outer epidermis and the underlying dermis. The epidermis is composed of a particular kind of tissue called stratified squamous epithelium. Epithelium consists of cells that are packed together very tightly, a feature that is most important to an organ that must cover and protect the rest of the body. It is called squamous, which means “flat” in Latin, because its cells are flat and fit together like tiles. The word “stratified” describes the dozens of layers of cells that are piled up to create the epidermis. These cells form four or sometimes five strata, with their own characteristics and roles to perform.
The stratum basale, or basal layer, lies on a thin piece of tissue called the basement membrane, which is next to the dermis. The basal layer cells divide continuously throughout life, supplying new cells called keratinocytes for all the layers above the basal layer. About one-fourth of the stratum basale cells are called melanocytes because they produce the pigment melanin. As the keratinocytes are pushed up, they acquire a spiny shape; for this reason, the layer above the basal layer is called the stratum spinosum. While in the spiny layer, the upward-moving cells begin to produce the protein fibers that will eventually become waterproof keratin. As the spiny cells are moved further upward, they begin to flatten out. The layer that they form at...
(The entire section is 1215 words.)
Disorders and Diseases (Magill’s Medical Guide, Sixth Edition)
The complex anatomy of the skin allows for the development of many possible defects and diseases. Three disorders that modern medical science attempts to understand and alleviate are psoriasis, cancer, and the many varieties of contact dermatitis.
Psoriasis, one of the most common of all skin conditions, is said to afflict about 3 percent of the American population. It commonly runs in families and affects both sexes equally. It may develop in childhood or old age but typically appears in the second or third decade of life. It most frequently occurs as scaly patches, or plaques, on the elbows, knees, and scalp but may appear on the back, belly, buttocks, and legs. Many people with psoriasis experience itching; surprisingly, some do not.
Human epidermis cells usually take about twenty-eight days to move from the stratum basale, where they are produced, to the top of the stratum corneum, where bathing removes them. This means that the cycle of normal epidermal cells in transit through the skin is accomplished in a month or more, allowing the cells time to mature. In psoriasis patients, this transit period is as short as four days. The reproducing basal cells divide five to ten times too rapidly, and the epidermis thickens enormously, but in patches. The skin cells of psoriasis patients are so abnormal that the patients’ immune systems form antibodies that attack and destroy them, further damaging the ruptured,...
(The entire section is 1155 words.)
Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
Research in dermatology both borrows from and sheds light upon many other branches of medical science. Immunology, endocrinology, biochemistry, surgery, and oncology are just a few of many.
Diseases of the skin can reveal the presence of many otherwise unseen internal disease conditions. Shiny, thin, reddish-yellow patches on the shins may be a sign of diabetes. Prediabetics are also susceptible to repeated yeast and fungal infections of the skin and have poor wound-healing ability.
Too little thyroid hormone causes coarse hair; thickened, dry, cool skin; and rough plaques on the shins. Too much thyroid hormone causes thin hair, excessive sweating, and, surprisingly, identical rough plaques on the shins.
Abnormally dark skin can be a sign of drug side effects, the presence of heavy metals, poor adrenal gland output, or pituitary tumors. Skin may also darken from excess iron intake or, very noticeably, from a widespread malignant melanoma.
Various bowel diseases may also cause skin conditions. The small intestine defect involving a flattened, malfunctioning lining can produce severely itchy blisters on the limbs and the back. Ulcers in the large intestine often produce deep, dirty-looking skin ulcers.
The presence of cancer in the breast, bowel, or lungs may precipitate thousands of external wartlike growths or flat, waxy-surfaced growths. Similarly, the gradual appearance, usually on the...
(The entire section is 622 words.)
For Further Information: (Magill’s Medical Guide, Sixth Edition)
Goodman, Thomas, and Stephanie Young. Smart Face. Englewood Cliffs, N.J.: Prentice Hall, 1988. An easy-to-read explanation of skin structure, problems, and care, with special emphasis on delicate facial skin. Contains an extensive appendix of consumer product information.
Jacknin, Jeanette. Smart Medicine for Your Skin. New York: Putnam, 2001. An accessible and comprehensive guide to skin problems and solutions that include traditional therapies and alternative medicine choices.
Lamberg, Lynne. Skin Disorders. Philadelphia: Chelsea House, 2001. This brief volume is an introduction to the study of skin problems. Contains a very helpful glossary, a bibliography, and a list of organizations to contact for more information.
Lees, Mark. Skin Care: Beyond the Basics. 3d ed. Clifton Park, N.Y.: Thomson/Delmar Learning, 2007. A text for estheticians and students in the field that provides practical information on treating many kinds of skin problems and discusses topics such as rosacea, sensitive skin, hormones and menopause, and postlaser skin care.
Mackie, Rona M. Clinical Dermatology. 5th ed. New York: Oxford University Press, 2003. A text written for dermatology students but useful to the general public for more precise and detailed information than that contained in popular works. Illustrated in color.
Siegel, Mary-Ellen. Safe in the Sun....
(The entire section is 327 words.)
Skin (International Dictionary of Psychoanalysis)
The skin is of interest to psychoanalysis because it is anaclitically related to narcissism, because it is an erotogenic zone, and because it is the object of particular kinds of assaults. Manifestly, the skin is a potential vector for the main instincts (attachment, libido, destructive impulses).
At the end of the first essay of Three Essays on the Theory of Sexuality (1905d), in connection with his notion of polymorphous component instincts, Freud treated the skin as an erotogenic zone specifically excitable by the sadism/masochism "pair of opposites," in contrast with the eyes, which he conceived of as the bodily seat of the voyeurism/exhibitionism antithesis. Later, in his paper " 'A Child Is Being Beaten'" (1919e), he described and analyzed the basic scene in masochism: an active adult beats a passive child, while another child bears silent witness to the event.
The skin has a particular place in the evolution of living beings: while the husk characterizes the vegetable realm and the membrane the animal realm, the skin is peculiar to vertebrates. In the development of the embryo in vertebrates, the ectoderm gives rise to both the skin and the cortex, so that the skin is in a sense the surface of the brain. The structure of the skin is complex in that it is a sense organ that contains the other sense organs. It comprises several interlocked layers of greatly varied structures. The skin and the sense organs that it envelops constitute an interface ensuring the individual's contact with the outside world. Like most outer coverings or membranes, the skin has a twofold nature: it is a protective shield and it facilitates the communication of meanings. Freud mentioned this nature in his discussion of the "mystic writing pad" (1925a ), on which traces and signs are inscribed. The skin helps give the body its form and coherence. The human body can more readily assume a vertical posture because the skin protects and holds in the skeleton and musculature. The unity of the individual thus depends on the skin.
Certain areas of the skin (mucous membranes, erectile tissue, hair on the head, pubic hair, hollows) are especially sensitive to sexual arousal (in comparison with overall presexual skin-to-skin contact). Didier Anzieu has advanced the hypothesis of a fantasy of a skin common to mother and child, and on that basis he developed the idea of a skin egon idea that converges with Esther Bick's notion of a psychic skin and Wilfred R. Bion's concept of container/contained. For Anzieu, this fantasy of a common skin contributes both to the narcissistic foundation of the individual and to the anaclitic reinforcement of the sexual instinct.
In sadism and masochism, humans experience a mixture of pleasure and pain. Here the fantasy of a common skin is replaced by the fantasy of its being ripped off, which is necessary if the individual is to progress toward autonomy but also is a source of guilt feelings. Mother's and child's joint cathexis of the newborn's skin is immediate and is sometimes a source of sexual pleasure. Indeed, if the mother does not spontaneously cathect this first contact, any of a large number of pathologies, ranging from asthma to autism, may result.
Psychodermatology has shown a correlation between flaws in the ego and skin disorders. The greater the impairment of the ego, the more seriously the skin seems to be affected.
See also: Adhesive identification; Anzieu, Didier; Bick, Esther; Body image; Dream screen; Erotogenic zone; Infant development; Infant observation; Isakower phenomenon, the; Masochism; Object; Protective shield; ; Skin-ego; Tenderness.
Anzieu, Didier. (1990). Formal signifiers and the ego-skin. In Didier Anzieu et al. (Eds.), Psychic envelopes (Daphne Briggs, Trans.). London: Karnac Books. (Originally published 1987)
. (1989). The skin ego (Chris Turner, Trans.). New Haven, CT: Yale University Press. (Originally published 1985)
. (1994). Le penser: du moi-peau au moi-pensant. Paris: Dunod.
Freud, Sigmund. (1905d). Three essays on the theory of sexuality. SE, 7: 123-243.
. (1919e). "A child is being beaten": a contribution to the study of the origin of sexual perversions. SE, 17: 175-204.
. (1925a ). A note upon the "mystic writing pad." SE, 19: 225-232.