The skin in health and disease

Front matter

Health^Disease

NATIONAL LIBRARY OF MEDICINE

LTH PRIMERS.

Prefatory Note

The writer has endeavored to make this Health Primer serve both as a guide for the preservation of the health of the skin, and as a popular dictionary or encyclopedia in matters pertaining to Dermatology.

He has therefore sought to introduce in its pages not only the medical terms used in reference to Diseases of the Skin, but also the popular names given, both those which are rightly and those which are wrongly applied. If, therefore, information be sought in reference to any particular matter, it will be well to consult first the index, which has been made particularly full.

It is hoped that this little book may be of much service in clearing up this vexed subject in the popular mind, and that by its means disease may be avoided, or, when present, that it may be recognized and proper aid sought for and applied.

i* y

Chapter I. Anatomy And Physiology Of The Skin

THE object of the present little book is fourfold ; first, to correct certain popular prejudices in regard to the subject of diseases of the skin ; second, to give directions in regard to the care of the skin in health and for the prevention of disease; third, to afford a certain amount of popular information as to the principal diseases which affect the skin, their recognition and home management ; and, lastly, to give directions whereby the patient may assist the practitioner in the cure of this class of diseases by his diet, hygiene, and mode of life, together with the manner he should himself treat the diseased portions.

These points will best be considered more or less conjointly ; and we will therefore divide our subject into two main parts, as indicated in the title. First, treating of the skin in health, its functions, and the care to be given it; and, second, the diseases to which it is liable, their recognition and management. In order to properly understand what is to follow, a brief exposition of the skin, in its physiology and anatomy, will be necessary.

The skin is the largest single excretory organ of the body, and upon the proper performance of its functions depends, to a large degree, the health of the individual. The skin is generally spoken of as simply a covering for the rest of the body, an outer garment of tissue which serves to enclose and protect the parts within, to give symmetry, shape, and beauty to the human form. While it fulfils these ends in a marvellously perfect manner, it has functions which are peculiar to itself, and which it performs with as wonderfully satisfactory results as those executed by other organs of the body which receive more credit for their work.

To fulfil its many duties, the skin is composed of very many different elements, all united in a harmonious structure, and thus constituting one vast organ, which, by its constant repair from within, resists the many agencies which constantly tend to destroy its integrity. To appreciate this latter remark, let any one note the injuries done to a kid glove when exposed as in a fall, and compare with it the power of the human skin in resisting and repairing injuries.

The skin may be roughly divided into two general portions, — the deeper, called the corium, cutis vera, true skin, or derma, and the outer, cuticle, scarfskin, or epidermis (Greek, Itti, upon, and Bipfia, skin). The inner, or deeper portion, which forms the largest mass of the skin, is composed of firm and elastic connective tissue-fibres, which interlace so as to form a structure resembling felt, which is extremely tough, and yet so elastic as to yield to every movement, and to regain its former position and state with a perfection which

STRUCTURE OF THE SKIN.

could not be excelled. The extent of this suppleness can be best appreciated when the skin becomes altered by disease, as is not at all uncommon when, in certain

Fig. i.

i

Section perpendicularly through the healthy Skin.

a, Epidermis, or scarfskin ; b, Rete mucosum, or rete malpighii ; c, Papillary layer ; d, Derma, corium, or true skin; e, Pannicnlus adiposus, or fatty tissue j A g, h, Sweat gland and duct ; i, k, Hair, with its follicle and papilla ; /, Sebaceous gland.

cases, it is what is called hide-bound, as in scleroderma, or when such an affection as eczema has so changed its state that every movement at an affected joint will cause deep and painful cracks or fissures.

At its under surface the meshes of the corium become larger and larger, until we reach what is called the subcutaneous cellular tissue, which is very loose, and connects the skin' with the parts below ; and it is this which permits so much motion. This subcutaneous cellular tissue, in some parts of the body, is filled with fat, and forms the panniculus adiposus ; and it is here that most of the fat in corpulence is deposited. It is this tissue, also, which becomes filled with water in dropsy. The outer surface of the cqrium is not even and smooth, but is thrown into multitudes of elevations called papillce, and this portion takes the name of pars papillaris, or papillary layer of the skin. These minute elevations, or papillae, are exceedingly numerous, in some parts of the body there being as many as four hundred on every square line of the surface, that is, on each space a twelfth of an inch square.

It is this corium, derma, or true skin, which makes the mass of the leather' used in commerce, where it is seen to vary from the most delicate kid to the coarse sole-leather, in which latter the separate fibres are readily seen with the naked eye. In this deeper skin are situated the organs of which we shall speak later, the sweat and sebaceous glands, the hairs, as also the nerves, blood-vessels, and absorbents or lymphatics of the skin.

The outer layer of the skin, the epidermis, cuticle, or searfskin, is not composed at all of fibres, but, on the contrary, of separate roundish elements called cells. These, of course, cannot interlace, as do the

STRUCTURE OF THE SKIN: EPIDERMIS. II fibres of the corium, but are piled upon each other in layers to a varying extent in different parts of the body. Thus, upon the soles of the feet the epidermis may attain great thickness ; also upon the palms, or wherever friction calls for more protection of the soft parts beneath j whereas on the face this layer is very thin.

The epidermis, outer, or scarfsldn, is also divided into two portions, — the outer, in which the scales are all flat, hard, horny, and lifeless, only waiting to be thrown off or removed by friction, and a deeper portion, in which the cells are round or many-sided, are soft and moist, are in fact growing and developing to replace those removed externally. This deeper, moist, or succulent part, which dips down between all the papilla of the corium, has received the name of reie mucosum, or rete malpighii, from the name of the anatomist Malpighi, who first described it. It is this epidermal layer which is removed by a blister, and which is frequently rubbed off in slight accidents, when the surface beneath feels raw and oozes a little clear liquid, or possibly a little blood. As long as accident or disease destroys only this outer epidermal layer, no scar is produced ; but when in any way the corium, or true skin, is destroyed, a scar or cicatrix results, varying in severity according to the depth of the destruction. Thus, many slight burns remove the epidermis only ; whereas, those which are followed by any loss of skin, or ulceration, will leave scars which may prove very unsightly.

It is this epidermis which forms the covering of many eruptions on the skin, as in the water-blisters of "cold-sores," " shingles," and chicken-pox. It is also raised in little vesicles, or water-blisters, in eczema; and later in this disease the epidermis is largely removed, and we have a surface which is raw and weeping, but one which, however sore, always heals without a scar, because only the epidermal layer is destroyed. Many skin diseases affect this outer layer alone — as some of the parasitic diseases, those due to derangements of color, etc.; while many others are located in the true skin, or derma; of these latter, some are destructive, and leave scars; others are entirely removable by absorption, and leave no traces of their existence.

The color of the skin depends upon this outer or epidermal layer. If it were entirely removed, the surface would be of almost a blood-red color, owing to the abundant blood-vessels found everywhere in the corium. Where the epidermis is thickest, as upon the palms and soles, we lose almost entirely the red, and have a yellowish-gray tint ; where it is thinner, we have the well-known pinkish flesh-color, and when a part becomes unusually flushed with blood, as in inflammation, and also in blushing, the red color predominates, the filled blood-vessels showing through the epidermis.

In the negro, the dark hue of the skin is due to the presence of a pigment, or coloring matter, in the lower layers of cells of the epidermis, that is, in the rete mucosum, the part directly above the papillae of the true skin. The corium, or true skin, which is made up of fibres, does not share at all in this pigmentation.

When there are discolored marks on the skin, as in freckles, moth-patches on the face, etc., the color deposit takes place in this deeper layer of the epidermis ; hence, they are very difficult of removal, because, in order to take away all the coloring matter at once,

STRUCTURE OF THE SKIN: BLOOD-VESSELS. 1 3 this portion of the skin would have to be removed down to the papillae, as in the case of a blister. Now, this is painful and troublesome ; and, moreover, experience shows that it would be useless to blister off such deformities, because we not unfrequently see blisters on different portions of the body actually followed by staining of the skin, where no such staining existed previously. We can, however, not unfrequently, by proper stimulants, induce an absorption of the pigment, or produce rapid change in the skin, when the new-formed cells will not have the color.

Returning now to the corium, or true skin, we find in it a number of elements which should be understood.

The blood supply to the skin is very abundant, as may be judged from the fact that even a fine needle cannot be introduced into it without drawing blood from some capillary or delicate blood-vessel. At the upper or outer portion of the corium the blood-vessels, or arteries, which have become exceedingly fine and delicate (and are called capillaries, from the Latin capillus, a hair, so very minute are they), rise into each one of the many papilla, or elevations of the papillary layer, and doubling upon themselves they descend again, and become veins, and finally enter into the larger veins, whereby the blood is carried again to the heart and the lungs to be purified. The outer or epidermal layer contains no blood-vessels, its cells are nourished indirectly from the portions beneath. Hence, we do not draw blood by a blister, or when the skin is lightly scraped or rubbed off ; it is only when we reach the deeper layer, or corium, and wound it, that we obtain blood.

The nerves of the skin are a very important ele- 2 ment, and the abundance of their distribution may be also judged from the pain caused by the entrance of a pin, or even the penetration of the minute sting of an insect. This very abundant nerve supply of the skin, which is undoubtedly for the purpose of protecting us against injury, is accomplished by the most delicate division and distribution of the nerves, until their extremities are lost among the deeper cells of the epidermis. It is exceedingly difficult to trace these nerve-fibres, and this has only been accomplished quite recently by means of staining the sections of the skin with chloride of gold. This kind of nerve gives ordinary sensation of pain, heat, and cold, etc. ; but there is a somewhat different class or arrangement of nerves, whose function is to preside over the special sense of touch. These end differently ; they enter the papilla of the corium, and appear to be wound up into a little knot. These little knot-like bodies are called tactile corpuscles, because the sense of touch is supposed to reside in them. They are always found on the palmar ends of the fingers, and are most numerous there, but are present to a lesser degree over most of the surface. They are found in about one out of every four papillce.

There are two varieties of glands contained in the skin, — the one for the secretion of sweat, called the sudoriparous, or sweat glands, and the other for the secretion of an oily or greasy substance called sebum, these latter glands receiving the name of sebaceous or sebiparous glands.

The sweat glands are in the form of minute tubes of about 4-^5- of an inch in diameter, which are twisted into coils at the very deepest portion of the corium, or true skin, or even in the subcutaneous tissue, and

STRUCTURE OF THE SKIN: SWEAT GLANDS. 1 5

Fig. 2.

1'

then extend through the entire thickness of the skin, and open on the surface ; as the tube or duct passes through the epidermis, it makes a number of spiral turns, like a corkscrew. The openings of the sweat glands are arranged somewhat regularly, and may be seen with a magnifying-glass, especially on the palms of the hands, in rows between the slightly elevated ridges of the skin. (See Fig. 3.) These glands are very numerous in some parts ; on the sole of the foot and palm of the hand there being about 2700 in each square inch, while on the cheeks there are but about 550 in the same space, and on the forehead about 1250. According to careful computation, the total number of sweat glands in the

1 j 4.^ i„ „1 i. Horny layer of epidermis

body amounts to al- cosum » * p api i[ ary i ay( most 2,400,000; and as each little gland, r wmi

Sweat Glands from the Palm of the Hand. Magnified twenty times.

Rete muayer. 4. Derma, or true skin. 5. Subcutaneous cellular tissue. 6, 8, 9. Sudoriparous or sweat glands.

when its coil is unravelled, would measure about y 1 ^ of an inch, their entire length amounts to not less than 153,000 inches, or about two and a half miles. We can readily understand, therefore, the very

great importance of the skin as a secretory organ, when we consider the vast surface thus presented ; and direct experiments fully confirm the judgment thus formed.

The action of these minute glands is not intermittent, but continuous; and during the entire time sweat is exhaled in the form of vapor, or insensible perspiration ; and only when the body becomes much heated, as by exercise or otherwise, does the perspiration manifest itself to the eye or touch. The total quantity of fluid thus given off by the skin is subject to the greatest variations, according to temperature, moisture, exercise, quantity and quality of food and drink taken, etc. In the average person in health, however, careful experimenters agree in placing the amount at about two pounds, or pints, daily, a quantity almost equal to that excreted by the kidneys. The office of this cutaneous perspiration is largely

Fig- 3-

Openings of the Sweat Glands on the Palm of the Hand. Magnified four times.

1. Openings of glands. 2. Furrows between the lines of openings.

STRUCTURE OF THE SKIN : SWEAT GLANDS. I J to regulate the temperature of the body by the evaporation from the surface; the cooling effect of fanning results from the evaporation of the moisture on the skin. The more violent efforts of the skin to reduce temperature are seen naturally in warm weather, or artificially in the Russian, or Turkish hot-air bath, when, as the body becomes more and more heated, the glands secrete more and more profusely. All know that if one sweating profusely gets in a draught of air, great cooling will result.

It can be readily understood how, with this vast secreting surface exposed to the changes of the atmosphere, we can readily " catch cold" from chilling the surface in a draught, or from exposure too thinly clad, and by a "check of perspiration" cause congestion of internal organs. When animals are completely covered with an impermeable coating, as by varnishing the surface, death always takes place; and the story is current among physiologists, that a child who was covered with gold-leaf, in order to represent an angel in the ceremonies attending the coronation of Pope Leo X., died a few hours after the coating had been applied. The importance, therefore, of the proper care of the skin can hardly be over-estimated, that these many pores through which this vast amount of fluid passes out of the system may not be clogged. Proper bathing and friction are all-essential elements of a healthy skin, and a perfectly active skin means a great deal towards a perfectly active general system.

Besides the sudiparous or sweat glands, we have another glandular apparatus, situated in the skin, which is of especial importance, particularly as one of the most common and annoying of skin diseases, acne, 2* B has its seat in them ; these are the sebaceous or sebiparous glands.

While the sweat glands are composed of a single tube coiled upon itself at its lower extremity, which is situated in the very deepest portions of the skin, the

sebaceous glands are rarely, if ever, formed of a single tube, but have a duct, more or less straight, with a mass of glands grouped about its deeper end, forming what is known as a racemose gland, from the resemblance to a cluster of grapes (Latin, racemus).

The sebaceous glands are almost invariably connected with the Greatly mag- hairs; upon hairy parts, as the scalp,

,tV 5 ersed bf thebaic the y f0I " m W^"

ages at the sides of the hairs, and their ducts open into the hair follicles. Generally, there are two to each hair, situated opposite each other; but in some situations large hairs have a number, even from four to eight, situated around them, forming a sort of collar about the hair. In some situations, on the other hand, as on the

Large Sebaceous Gland.

nified.

i. Hair in its follicle. 2.3, gland. 6. Excretory duct traversed by 1

STRUCTURE OF SKIN: SEBACEOUS GLANDS. 19 smooth face, nose, forehead, etc., the hairs are very small and rudimentary, while the sebaceous glands are large, and the hair there appears as an appendage at the side of the comparatively large gland. Very few of the glands open directly on the skin without a connection with a hair, although this latter may sometimes be so small as to escape ordinary observation.

These sebaceous glands are very minute affairs, having a diameter from one one-hundred-and-twentieth up to one-twelfth of an inch, as in some on the nose and elsewhere. They are also short compared to the sweat glands.

The secretion from these glands is of an oily nature, and, when in a healthy condition, is perfectly fluid at the temperature of the body. The quantity is not very great, and the main function of the secretion appears to be to keep the skin in a flexible state, though the amount of solid matter thrown off thus must be of some importance in the economy.

When there is disorder of these glands, we have, as mentioned before, acne, and also one of the various forms of dandruff, or seborrhea, and comedo, or what are popularly known as flesh-worms, etc. Under certain circumstances they fail to act, more or less, and we have a hard, dry skin, xeroderma. In the proper care of the skin, the oily products of these glands, which adhere to it with the dead epidermal matter, are removed continually ; whereas, neglect allows all

Sebaceous Gland, with a small hair attached. Greatly magnified.

1. Hair. 2. Sebaceous gland.

this to accumulate, the openings of the sebaceous, as well as those of the sweat, glands are clogged, work is thrown on other organs of the body, and slow disease is engendered.

In this connection may be mentioned an element in the anatomy of the skin which was omitted, in the previous general consideration of the subject, for reasons which will presently appear, namely, the muscles of the skin. In certain animals a very abundant muscular layer is developed immediately beneath the skin, so that they possess the power of wrinkling it and shaking it, in order to rid themselves of dust, insects, etc. In man this is- found only in a few situations and moderately developed ; but the human skin possesses within its structure a certain amount of muscular fibres, which are of especial importance in the present study of the sebaceous glands.

These muscles in the skin belong to the class of what is called smooth, or unstriped, muscles, which differ from those composing the mass of muscles of the limbs, etc., in that they are not controlled by the will; they are, therefore, called involuntary muscular fibres. These are, of course, extremely small, but are quite readily seen by the microscope. They extend from near the end, or deeper portion, of each hair-follicle, in a slanting direction, and terminate, or are inserted, near the outer surface of the corium or true skin. The name given to these muscles is arrector pili, or, in the plural, arrectores pilorum, so called because, when they contract, they cause the hair to stand more or less erect and to protrude a little from the skin ; thus, in the cat, when excited or enraged, all the hairs become

STRUCTURE OF THE SKIN: MUSCLES.

Fig. 6.

Hair in its follicle, Sebaceous Glands, and Muscle, from the Scalp.

i, 2, 3, 4. 5, 6. and its follicle Muscles, arrcctores pilorum. 9, io, n.

Sebaceous glands. 12. Opening of hair follicle and duct for sebaceous glands.

Hair

7. "

erect and bristling. The action of these muscles maybe well observed in man in what is called "goose-skin," when, from exposure to cold, or sometimes from emotional causes, the skin may be observed to be thrown into numerous projections. This condition may be readily observed on entering a warm bath : if the portion not immersed gets a little chilled, and if the surface be yet dry, the fine hair on the arm may be seen to rise and stand more or less erect, and, as the condition subsides, the mass of hairs sink to their former position all together. This may be repeated several times, all rising and falling together, like afield of grain under the wind. It was to this action that Shakespeare referred in the utterance of the ghost to Hamlet, in the lines :

I could a tale unfold, whose lightest word

Would harrow up thy soul ; freeze thy young blood ;

Make thy two eyes, like stars, start from their spheres ;

Thy knotted and combined locks to part,

And each particular hair to stand on end,

Like quills upon the fretful porcupine.

But these muscles have another action which is very important, and that is the emptying of the sebaceous glands. These latter structures have no muscular coat of their own, and their secretion, which is constant, oozes out upon the surface. Now, where there are large hairs, as upon the scalp and beard, these muscles more or less embrace the sebaceous glands, and by their contraction they empty them from time to time, and by this means prevent an accumulation or prevent the openings from becoming clogged.

On the face, back, and chest, however, where we have acne developing, and where these glands are apt

STRUCTURE OF THE SKIN: THE HAIRS. 2$ to become plugged up with the black specks so often seen, these muscles are almost entirely absent, and the secretion, having no particular expulsive force, readily becomes impacted, and, if at all hard, fails entirely of gaining exit.

Another reason of the presence of acne on the face is the anatomical fact that, over most of the surface of the body, the sebaceous glands are connected with hairs of some size, and their ducts open into the follicles of these latter, and their hairs, by their continual growth, keep the orifices of the glands free ; whereas on the smooth part of the face (nose, forehead, cheeks), also on the neck and chest, the hairs are insignificant, and cannot thus assist in the outflow of the sebaceous secretion, and often even act as impediments by themselves blocking up the openings.

The hairs and nails are simply portions of the epidermis, or outer layer of the skin, altered in shape and structure to fulfil the ends assigned them. But the hairs are situated much more deeply than one might infer from this statement, and the longest and largest of them reach down through the entire thickness of the true skin or derma; though the finest, downy hairs, called lanugo, are very superficially inserted.

Almost the entire surface of the body is provided with hairs of some sort, with a few exceptions, as the palms of the hands and the soles of the feet, etc., though over some portions of surface they are so fine as to be hardly discernible with the naked eye. Each hair is divisible into two portions, the root and the free extremity. The root is somewhat pear-shaped, that is, is a trifle larger below than at the surface of the skin, and its tissue is much softer than the exposed portion of the hair ; it is indeed succulent, in the act of growing. At the deepest portion of the hair-follicle, or cavity in which the hair rests, there is a certain anatomical structure which is of the greatest importance in reference to the growth and vitality of the hair, namely, the hair papilla. This is, of course, quite distinct from the papillce, which we have seen to cover the surface of the corium or true skin ; it is situated deep in the tissues, at the bottom of each hair-follicle and projects into a small cavity at the lower end of the hair. This little hair papilla, which is only one-fifteenth of a line, or one one-hundred-andeightieth of an inch long, is of vital importance to the life of the hair, as from it the materials come for the growth of the hair, there being a minute blood-vessel in its interior; and it is believed that the reproduction of the hair, after it is lost from any reason, takes place from this papilla. Conversely is it also true that, as long as this papilla is intact and in a healthy state, the hair will be reproduced, even though extracted artificially. Thus, "plucking the hair out by the root " does not destroy the life of the follicle ; only the hair is removed, the papilla from which it regrows remains.

This explains the reason why so many of the methods for the removal of superfluous hair, especially from the faces of ladies, are generally useless, or worse than useless. If they are pulled out with the tweezers, there is a still greater stimulus given, and the hairs return yet more coarse and obtrusive. Shaving with the razor but removes the portions external to the skin, and at the same time stimulates greater growth.

Numerous remedies have been brought forward from time to time for the removal of these obnoxious hairs, (this hairy state is known medically as hirsuties or

STRUCTURE OF THE SKIN: THE HAIRS. 2$ hypertrichosis ,) and the name by which they are known, depilatories, would indicate that they are capable of accomplishing the desired end of removal of the hair. A moment's consideration, however, will show the uselessness of the hope, which experience has also demonstrated to the writer time and time again. The directions given with these preparations are that they should be moistened with water, spread over the part and left on a few moments, or until they cause a little burning, when the surface is to be scraped with a blunt instrument, as a paper-cutter, and the hair will be found to come off with the paste.

But what has been accomplished ? Simply this : the remedies which form the powder are found to be such as have the power of dissolving the hair to a greater or less degree, such as lime, baryta, etc., and after this has been done, the mass is scraped off with a dull instrument, instead of a razor, simply because the paste has softened the hairs more than soap softens the hairs in shaving. But the destruction has not reached deeper : the solvent may have penetrated a little further than would be removed in shaving, but it has not reached down and arrested the hair-producing power ; and it cannot. Therefore the idea of permanently removing these deformities by this means is a delusion and a snare.

The only method of really permanently removing superfluous hair is one which, in a measure, resembles that in which this is sometimes accomplished by disease, namely, by means of something capable of destroying the life and vitality of the hair papilla itself. This is accomplished artificially only by the treatment of each individual hair-follicle in its interior; and this may be done by the physician in one or two ways. I 3 have on several occasions seen ladies who had attempted this destruction of the papilla by means of a heated needle introduced into the follicle, and the attempt had been followed by the production of small, black, indelible stains, like a tattoo, at the point experimented upon. This was caused by the introduction of a little carbon or lamp-black, which had been deposited on the needle by the flame, deep under the skin, where it will remain during life. This same event has been recorded by others.