Rules for Studying Skin Diseases

We should have some rules as to the mode of studying skin diseases. The following are probably the best; they are taken from Fox:

1. The observer should always strip his patient so that the disease may be exposed to the fullest extent compatible with a due regard to the proper feelings and sensitiveness of the individual. To be satisfied with seeing a bit of a patch of disease in this spot, or just a spot or two there where the malady is most marked even, is often to run great risk of arriving at an erroneous diagnosis, if not to actually make one, certainly to miss the recognition of transitional stages, which are of the utmost importance in determining the general character and often the exact nature of a disease.
   
2. It is of much importance that mere stages of diseases should be regarded as stages and nothing else. Diseases must be dealt with in their entireties. Where the whole of a disease is made up in any particular instance of certain stages, in estimating the nature and characteristics of that disease one stage must not be regarded in particular - be thrust into undue prominence - at the expense of others. The several stages together constitute the disease.
3. A clear distinction should be drawn between essentials and accidentals. For instance, the essence of scabies is the acarus in its furrow. All else that follow - the follicular irritation, improperly called lichen, the ecthyma, the urticaria, which  may  occur in many different diseased states of the skin - is accidental, and due to the irritation and the scratching practiced.
4. It should be a point with the dermatological student to make as little as possible of mere superficial appearances and changes, because these are brought about as the result of, and are indeed often secondary to, more important and primary changes in the deeper parts.
5. It is important to pay special attention, as far as possible, to the primary anatomical seat of the disease. What the primary seats of individual diseases are, so far as regards cutis, cuticle, follicles, and the like, I shall discuss in another place in speaking of elementary lesions  and the individual diseases themselves.
6. Special attention should be paid to the fact of the character of an eruption being permanent, or transient, or interchangeable. The case of lichen plan us may be taken to illustrate this point. In it the characteristic lesion is a red flattened papule covered by the minutest scales. This is the sole lesion present. The papule never changes into a pustule or vesicle; but not so is it with the papule of eczema or variola. The tendency of a syphilitic papule is to become oftentimes a pustule or tubercle, which gives place to an ulcer, and so on. The eruption as a whole may be again capricious, appearing and disappearing suddenly, often in the course of a few minutes. This feature in itself is almost diagnostic of urticaria.
   
7. Those who are studying skin diseases should observe whether an eruption be uniform or multiform in character. Multiformity implies (a) the  co-existence of two  or more diseases, in which case there will be present the features of the two or more diseases commingled; or it implies (b) the existence (1) if the lesions be inflammatory - that is, if pustules or vesicles be present, of scabies,  or (2) if the lesions be degenerative, if ulcers and suppurating tubercles,  for example,  be present,  of syphilitic disease. The difference between the two main classes of cases, the complicated disease on the one hand and scabies and syphi­litic on the other, being that in the former there are no transitional stages observed, as in purpura urticans, pemphigus pruriginosus, impetigo and scabies; syphilis andscabies, etc.; whereas, in the latter class, they are present as between the papules, vesicles, and pustules of scabies, or the papules, tubercles, pustules and ulcers of syphiloderma. Multiformity as it exists in scabies and syphilitic eruptions—relates in each case to such different kinds of eruption, and the multiformity moreover in complicated or co-existent diseases is seen to be due to the commingling of such distinct lesions without transitional forms that the character of ultiformity becomes at once a very reliable guide in diagnosis; of course, other things help, as rest, development, etc., but multiformity is a good rough test of syphilis, scabies, or complicated diseases.
8. It is wise to note certain differences, not only as to the general nature and character of cutaneous diseases as they exist in the old and young, but also in reference to the same disease as it occurs in the old and young. The cutaneous diseases of childhood are essentially distinguished from those of the adult, in that they are uncomplicated by organic diseases of the internal organs, and by those more complex and profound perversions of nutrition which arise from overworked or badly used organs, such as gout, dyspepsia, free retention of excreta in the blood, rheu¬matism, and so on. They contrast with those in the old by the absence of coincident degenerative changes in the body, which are to be the lot of the man who passes the meridian of life. The cutaneous diseases of children are un¬complicated in this respect, and speaking generally, they are the result of the misuse of pabulum supplied to the body, or the direct consequence of improper diet. The case of eczema infantile may be taken as an example. But there is a difference in constitutional conditions - the diathetic conditions in the child who suffers from skin disease are different from those of the adult or aged. It does not take any long time to see how frequently the subjects of skin diseases in the young are strumous, and what an influence this diathesis has on the skin diseases of the young as contrasted with those of the middle-aged and of and beyond the later period of life; that syphilitic affections other than those hereditarily transmitted are specially the privilege of the adult, and so on; that in the advanced in years there are not only complicating organic diseases of internal organs, blood alterations due to malassimilation, degenera¬tive tissue changes such as cancer, but disease specially connected with decay of the nervous system, as in senile pruritus. But to put what I wish to enforce in a few words, I may say that, as regards kind, the diseases of children are the result of malnutrition from deficient or bad feed¬ing; those of the adult the result of malassimilation; those of the aged the result of degenerative, changes. As regards complications, diseases of the young are often closely connnected with the strumous diathesis especially; those of the adult with functional derangements of internal organs and malassimilation, such as dyspepsia, hepatic and renal torpor - and with the diathetic conditions, phthisis, rheumatism, and the commencement of gout; those of the aged are linked with nerve pareses and degenerations of the skin, as evidenced by increased pigmentation, atrophy of the glands, and of the nerves in the papillae, and also with organic diseases of important internal organs. All this is important therapeutically.
9. It is to be remembered that there is a difference in the conditions associated with skin diseases, as they occur in hospital and private practice. The constitution of the hospital patient is depraved by mal-hygiene and want of proper food, that of the private patient is depraved, no doubt by want of hygiene oftentimes, but also by overloading of the digestive organs, and not from actual want of food. But more than this; the nervous system participates in the latter much more actively in helping, controlling, or modifying the existing disease; and this as the result of the luxury enjoyed by the rich, and the greater mental toil undergone by the busy man of the middle classes, the effects of which, in both cases, are felt by the offspring. The old amongst the hospital patients show especially nervous symptoms connected with physical decay, and at the two extremes of life the evil consequences of uncleanliness are most marked, because there is less power to resist its influence - in the hospital patient.
10. There are differences in the same disease as seen in this  and other countries,  as  well as  a distinction to  be drawn between the several kinds of cutaneous affections occurring in this country and abroad. There is, indeed, a nationality of disease as well as of character or physique.
11. A very close relation exists in many instances bet­ ween cutaneous  disorders and functional disturbances in internal organs. Dr. Singer calls attention to this relation, and thinks that it is more frequent than is generally known, as the symptoms, meteorism, flatulence, eructations, loss of appetite, and constipation, may be lacking. Examina­tion of the urine with detection of the greater or less ex­cretion of indican will give one an index of how matters stand. Urticaria is nearly always accompanied by digestive disturbances. In the so-called idiopathic urticaria the amount of indican in the urine is' nearly constantly increas­ed. Collect the twenty-four hours' quantity and test from that as it varies during the day. He employed Obermayer's reagent. In certain forms of facial acne, and in nearly all cases of senile pruritus, he found a constant relation bet­ween the skin eruption and increased intestinal fermenta­tions at the lower portion of the small intestine. In some instances hyperaemic changes in the skin and mucous membrane have a common origin, as in lichen planus and pityriasis rubra, from disturbance of the sympathetic for example, and this is the explanation of the coincidence in the two diseases named, of the skin changes, and pyrosis, menorrhagia, and the like. In other instances the changes in skin and internal organs, instead of having a common origin, react the one upon the other, and the important point to notice is this: that the cutaneous troubles may be excited and intensified by internal troubles. There are four organs whose derangement excites or intensifies skin mis­chiefs. The stomach, the liver, the kidney, and uterus. In the vast majority of cases, it is rather intensification than excitation that the practitioner has to deal with.
12. It is important always to be aware of the fact of the bias impressed upon skin diseases by various diatheses especially the syphilitic, the gouty, the strumous, and the nervous.
13. Observers should  accustom themselves to examine microscopically the morbid products of skin diseases. The surgeon and the physician obtain most valuable indications from the examination of the minutest portions of morbid tissue and the juice it may yield; and the dermatologist is much to blame for an omission in this respect. The microscope affords very valuable assistance in the differential diagnosis of herpes, eczema, psoriasis, and tinea especially. For instance, inflammatory products are absent in psoriasis, present in the other three diseases; whilst in all forms of parasitic disease resembling herpes and eczema, as in so-called eczema marginatum, fungus elements are detected, provided proper care is observed.