There are two important disease of the skin with which we shall deal in this chapter-namely, pityriasis and psoriasis. In the former malady, in its typical form, the surface of the body is deeply reddened (hyperaemic), and covered by large and freely imbricated scales or flakes….

General Remarks.

There are two important disease of the skin with which we shall deal in this chapter-namely, pityriasis and psoriasis. In the former malady, in its typical form, the surface of the body is deeply reddened (hyperaemic), and covered by large and freely imbricated scales or flakes; hence the term applied to it- pityriasis rubra. In the disease there is no real inflammation in the form of new products. Hebra allies it to eczema, and upon the ground that “we occasionally find moist excoriated patches on other portions of the skin, especially in the flexures of the joints.” But this is infinitely rare; from beginning to end, there need be nothing but hyperaemia and scaliness present in the disease.

There is not necessarily any change in the corium tissue or the connective tissue, though the hyperaemia, if persistent, may be followed by hyperplasia and thickening of these parts, but only as accidental epiphenomena.

In psoriasis a somewhat different state of things obtains; there is hyperaemia of the papillary layer of the skin, with hyperplasia of the epithelial elements, but I believe the latter to be the more important of the two; and in this respect psoriasis contrasts with pityriasis rubra-the former psoriasis contrasts with pityriasis rubra-the former being essentially a disease of cell tissue, the later rather an hyperaemia, primarily.

Pityriasis Rubra.

Under this title two distinct types of diseases have been described- the one by Devergie and the other by Hebra. They both possess certain marked features which would entitle them to the designations they have received; but, as there are also marked differences in their course, and prognosis, they must and should receive separate consideration.

Pityriasis Rubra (Devergie).

This affection is chiefly met with in persons between the ages of forty and fifty, and commences by the appearance of well- marked redness, with a sharply limited margin on the anterior aspect of the trunk and limbs. As it advances new surfaces are invaded, the skin slightly thickens, and the increase may be so rapid that the entire skin may become involved in from two to four weeks. Accompanying this diffuse redness we find free desquamation of exfoliation of medium-sized epidermic scales, with more or less watery exudation, resembling sweat rather than the lymphy and plastic exudation of eczema. There is also an intense burning heat of the surface, so that the patient suffers from the warmth of his clothing and of the bed coverings at night.

The acute symptoms mentioned are tenacious, and the affection may persist in this condition for months, but in perhaps the majority of cases they gradually subside, and recovery takes place.

On the other hand, the acute phase of the disease may be followed by one that is subacute, but more persistent, and continue to harass the patient for years, gradually breaking down his health and terminating fatally, through the supervention of chronic diarrhoea or the development of pemphigus.

The prognosis is in the main favorable, except when it occurs in aged or debilitated subjects, or assumes the distinctly chronic form.

Pityriasis Rubra (Hebra).

Under this name Hebra has described a disease that is wholly different from the foregoing, and the principal characters of which are as follows:

The skin presents a persistent deep-red coloration, distributed over the entire surface, but without papules, vesicles, or any exudation. Scales are found in small numbers, but do not become a prominent feature of the affection.

The local subjective symptoms are insignificant.

The progress of the disease is remarkably slow, and in its early periods the general health is not notably affected; but little by little there is a gradual weakening of the vital forces, and fatal marasmus marks the termination of the patient’s sufferings.

It will be seen from the foregoing that the affections described under the same name by the eminent French and German authors differ from each other in every important respect, and are, in fact, quite distinct diseases.

Dr. Piffard has met with a number of cases of Devergie’s disease, but only a single undoubted example of the malady described by Hebra.

If, as asserted by Hebra, pityriasis rubra is always and unnecessarily fatal, treatment other than palliative is out of the question.

In Devergie’s affection, however, every effort should be made to cut short its progress, and benefit may be expected from baths, emollients, and therapeutics.

Soothing local applications, such as bran baths or a decoction of walnut leaves followed by oily inunctions, and later by oil of white birch, are important aids. Lotions corrosive sublimate 1-1000, or with hydrate of chloral 1-50 or 1-100, constitute an excellent application in pityriasis capitis. Sulphurated pomades have been advised; flowers of sulphur 1-30 or 1-60. For pityriasis of the face a pomade of calomel 1-100 is often efficient.

Arsenicum album is the principal internal remedy used by both schools. It produces pityriasis by its physiological action; its well known characteristics indicate its use; feverishness, with restlessness and thirst, for small quantities, etc.

Natrum arsenicum.-This drug corresponds very closely to the leading peculiarities of this disease, and I have prescribed it successfully in several cases. Its skin symptoms read: “Squamous eruption, scales, thin, white, and when removed leave the skin slightly reddened. If scales remain they cause itching, worse when warm from exercise.”

Arsen. iod. and Kali ars. are preparations that may be occasionally useful. I have had no trustworthy experience with either.

Other remedies may be indicated as follows:

Antimonium crud.-Brownish-red spots, like small hepatic spots, here and there.

Cantharis.-Itching, followed by burning, when scratching; tendency to formation of blisters; most suitable when the disease appears in children.

Cocculus.-Red, irregularly shaped spots on the skin, over the whole chest, and on the sides of the neck, behind the ears, without heat or itching, intolerance of both cold and warm air.

Conium.-Frequently recurring red, somewhat itching, spots on the body.

Graphites.-Pityriasis capitis, dryness of the skin, with cracking; localization of the eruption; tendency to cold from draughts of air; pains from changes of the weather; abundant desquamation from the hairy scalp.

Kreasotum.-Uneasiness during rest, with irritation, through out the body; child cannot sleep unless carried or fondled; scaly ulceration on face, elbows, wrists and fingers.

Lachesis.-Small reddish spots on face, neck and chest, which increase in numbers, become scurfy, and then disappear.

Ledum.-Aching, bruised feeling in the whole body; warm sweat of the hands and feet; bluish spots on the body like petechiae; eruption itching, with anxiety; coldness is affected parts.

Mezereum.-Chronic pityriasis capitis, loss of hair and great itching, brownish miliary rash on the chest, arms and thighs; phlegmatic temperament, with light hair.

Phosphorus.-Brown, bluish-red, or yellow blotches on abdomen and chest.

Sepia.-Brown-red hepatic spots on the skin.

Sulphur is advised by the two schools. Its pathogenesis contains the formation of furfur.

Tartar emet.-Eruption dependent upon gastric derangement, nausea and vomiting, with thick white coating on tongue.

Pityriasis Pilaris.

Devergie, who was the first to describe this rare dermatosis, states that in its most benign form it consists of a more or less localized eruption on the external aspects of the members, and especially the forearms and legs. The essential seat of the eruption is at the pilous orifices of the general surface, but not on the scalp. The only lesion is a minute papule, with a small adhering scale.

In more severe cases it may become generalized, with slight thickening of the skin about the follicle, forming a small, red pyramidal papule decked with a white scale. The skin between the papules is apparently unchanged.

There is little or no pruritus, and it apparently causes but trifling inconvenience to the patient,, except as it progresses from bad to worse.

It is exceedingly obstinate, and palliative and emollient treatment is our only resource.

When associated, as it may be, with pityriasis rubra, it presents a striking likeness to lichen, rubra and may possibly be in reality the same affection.

There is considerable discussion as to whether pityriasis is not a parasitic affection. Some observers claim to have discovered a special parasite in this affection, consisting a very minute spores, averaging a thousandth of a millimetre in diameter. The extreme smallness of the spores and their irregularity in size have induced M. Vidal to name the parasite Microsporon anomoeon or dispar.

This is a point that has not been fully settled as yet, and I prefer to class the disease among the squamous inflammations until further light has been thrown upon the subject.

Sepia and Natr. ars. are the principal internal remedies for pityriasis pilaris.


Psoriasis is a constitutional disease, characterized by cutaneous lesions of the squamous type.

This affection may appear in the early years of childhood, or at almost any later period up to and including so-called middle life. It rarely appears at either of the extremes-that is, during infancy or old age.

Its first manifestations usually take the form of small red papules, soon decked with a white scale. These may be few and scattered, or many and closely aggregated. The scaly papules increase at their periphery, becoming flattened patches from the size of a pea to that of a coin or even larger. When the progress of the disease continues, neighboring patches encroach on each other, and in time coalesce, giving rise to irregular gyrate forms. Coincident with the peripheral extension there is an increase in the infiltration or thickening of the skin, and the scales become large, imbricated, and more or less adherent. On forcible removal of the scales, a red infiltrated patch is brought to light, on the surface of which minute droplets of blood may be seen. After the disease has attained its maximum development, which may include the greater portion of the surface, it may remain stationary for an indefinite period, or may undergo a gradual involution and disappear. This is the course followed in not a few cases of mild type. A single attack of this sort, however, is exceedingly rare. In almost every instance the eruption reappears after a shorter or longer interval. In not a few cases a mild type there will be an appearance of the lesions at the beginning of the cold and a disappearance of them at the beginning of the warm seasons.

In cases even there the eruption is caused to disappear by treatment there is the same tendency to return, and this relapsing feature of the disease is one of its most important and most annoying characteristics. To such an extent is this true, that even with the most judicious treatment there is no certainty of radical cure. As a rule, if a person once has psoriasis, he may expect to have it always- that is, with certain intervals of freedom. The reverse of this is rare, as it is extremely exceptional for a patient to recover permanently, or to enjoy immunity for a term of years.

The subjective symptoms are usually unimportant, amounting at most to a moderate degree of pruritus, though in many cases this is not sufficient to be complained of by the patient.

The eruption frequently exhibits a more or less symmetrical disposition, and prefers the extensor surface, with a special predilection for the elbows and knees. The upper half of the body usually presents more lesions than the lower. It very rarely affects the palms or soles. When situated on the genitals it may excite an analogous condition of the mucous membrane.

The features of the disease are the more characteristic if account be taken of its negative signs; for in it there is an entire absence of any discharge, vesiculation or pustulation throughout the whole course of the disease. The characteristics above described constitute a primary condition.

The eruption affects (by preference) certain parts of the skin whose epithelium is thick, especially the elbows and knees. It may be partial or general. At the outset the disease may be attended by more or less pruritus. The increase of the patches is by centrifugal growth, and there is oftentimes a slightly red margin; the scales are shed, to be again replaced by others; in chronic cases the derma itself becomes very distinctly infiltrated and thickened. The general health is often apparently good. The disease is non-contagious, runs a chronic course, and is very prone to recurrence.

It is customary to make certain local varieties; they are:

Psoriasis capitis.-The head is one of the commonest seats of the disease, next to the elbows and the knees; the whole scalp may be affected, or there may be only one or two small points of eruption; when extensive, the disease travels on to the forehead, forming a kind of fringe along it at the upper part. There is co-existent disease elsewhere. The hair on the scalp thins out frequently when psoriasis attacks it.

Psoriasis faciei.-In this local variety of psoriasis, the patches are often circular; they are less hyperaemic, less thick, and less scaly than when the disease attacks other parts of the body, and they present consequently much similarity to tinea circinata, except that typical patches of the disease are seen in other parts of the body.

Psoriasis palmaris and psoriasis plantaris are important local varieties. These local varieties are infinitely rare. Of course, instances of so-called psoriasis palmaris and plantaris are common enough, but they are practically always syphilitic. Non-syphilitic psoriasis may occur, though rarely, in connection with general psoriasis. But when such a condition exists as the sole disease, it is syphilitic and nothing else, and the concomitance of sore tongue and other evidences of constitutional syphilis at once make the diagnosis certain. The skin in the affected parts is generally thick, and dry, harsh, discolored; the scaliness is not very marked, but the superficial layers peel off from time to time. Presently the surface cracks and fissures, and healing is very tardy; occasionally the surface bleeds. The muscular movements of the hand may be painful.

Psoriasis unguinum is mostly a complication of the inveterate form of psoriasis, but it may exist alone. The nails (and several are usually affected) lose their polish. and soon become opaque, thickened, irregular, and brittle; they are then fissured and discolored in lines (from dirt), their matrix becoming scaly.

Psoriasis also affects the scrotum and prepuce occasionally; the parts are swollen, red, hard, tender, scaly, fissured more or less, and give exit to a thin secretion, which adds to the scaliness; there are pain pruritus; and the local mischief may be the sole, or part only, of general disease.

Psoriatic syphilides.-Nozo asserts that psoriatic syphilides always indicate the presence of a grave variety of syphilis and that they occur most commonly in cachectic subjects. In some cases they may appear as late manifestations of the disease; and their development is favored by old age, alcoholism, congenital or acquired dryness of the skin, and perhaps, also, by gout. Cases occur concerning which even the most expert diagnostician may be in doubt as to whether the eruption is the ordinary psoriasis or a specific eruption.

When psoriasis is in progress of cure, the scales lessen and the reddened elevated surface beneath comes more prominently into view; but this diminishes gradually till the eruption disappears, leaving oftentimes no trace of its former presence behind. It may leave, however, pigmentary stains, the result of the congestion. It is in the disappearance clears, and the ringed form or psoriasis, circinata, or the lepra of old authors is produced.

Etiology.-We possess no certain knowledge as to either the proximate or remote causes of the disease. It is not uncommon to find an extensive eruption in those who otherwise appear to enjoy the most robust health; while, on the other hand, it may appear only during periods of temporary debility, as in women during pregnancy and lactation.. That the affection is constitutional and connected with similar conditions to those underlying eczema we have no doubt, and each year’s experience more strongly confirms this opinion. Some have claimed that the eruption is purely local or due to the presence of a parasite. Positive evidence of this is wanting. Others pretend that it is but a relic or syphilis handed down from a remote ancestor. This view also has little to support it.

Psoriasis is often hereditary. It attacks males more than females and is most common between the ages of fifteen and thirty. Persons of sanguineous temperament are most liable to the disease perhaps, and it is seen in persons of all classes of society, and mostly in summer and winter.]

Prognosis.-The disease is mostly difficult of cure and has a tendency to recur. The most obstinate cases are those of psoriasis nummularis of the back and buttocks, in which there is much elevation and thickening and deep redness; and psoriasis about the hands and feet.

Diagnosis.-In well-marked and typical cases there can not be the least difficulty in diagnosis, especially to any one who has already seen an example of the disease. Unfortunately, however, cases are not always typical; and we must learn to distinguish psoriasis from syphilis, eczema, and dermatitis exfoliativa. As we have already stated, eczema may closely resemble psoriasis. In like manner the latter disease may closely counterfeit the former in its outward appearance; and in this particular case the diagnosis will be by no means easy, nor arrived at a glance, but only by careful consideration of the case in all its bearings. A squamous syphilide may closely resemble psoriasis; but here the history will aid us greatly if we bear in mind a few fundamental facts. In psoriatic cases of long standing we will have the history of repeated outbreaks of eruption, but they will all have presented the same general type- that is to say, a repetition of the same kind of eruption- a squamous syphilide will probably have been preceded by other eruptive attacks; but these have been in all probability a different sort of eruption-papular, pustular, or what not. Syphilis rarely repeats itself in its manifestations. If in addition we learn from the patient the prior existence of the primary lesion, or if we find other co- existing lesions, as alopecia, mucous patches, throat trouble, etc., we should not long remain in doubt as to the nature of the eruption about which we have been consulted. The existence of squamous lesions on the palms and soles in connection with squamous patches on the general surface is evidence positive of syphilis. In psoriasis the epidermic proliferation or desquamation is much greater than in syphilis. We have known a case of exfoliative dermatitis to be mistaken for psoriasis; but if we recollect that the characteristic feature of the former disease is the exfoliation of quite extensive laminae, of not very greatly thickened epidermis, sometimes several square inches in extent, there is no excuse for mistaking the one disease for the other.

Psoriasis and syphilis may of course coexist. There will be but little difficulty in differentiating the respective lesions.

Psoriasis may coexist with eczema, both presenting typical lesions, or we may have lesions of mixed character, in which it would be hard to say which disease predominated. Certain diseases of other organs appear to bear a close relationship to psoriasis. This is notably true of arthritic affections and also of asthma. As a rule, these do not coexist with the psoriasis, but manifest themselves during the time that the skin is free from eruption, alternating as it were with the cutaneous lesion.

Treatment.-It is but a few years since the chief reliance of the old school in the treatment of psoriasis was the internal use of arsenic and the external use of tar. Slow and tedious was the cure. Now, however, they possess an agent which they claim exhibits a remarkable energy in the control of the eruption. We allude to chrysarobin. This is employed in various ways, but the one seemingly most satisfactory, is a mixture of thirty grains of the drug with one ounce of traumaticin (liquor gutta- percha). This should be pained on the spots daily until a considerable degree of local irritation is produced. Sedative applications should then be applied for a few days, and the skin allowed to recover from the effects of the drug. A single course of this sort will cause most of the spots to disappear- that is, as regards scale formation and infiltration- and these spots will usually appear distinctly white and anaemic in comparison with the surrounding skin, which has been darkened by congestion produced by the chrysarobin. Unless the eruption was limited both as to size and extent of the lesions, we will find many patches in which complete recovery has not taken place. These will require additional applications. Chrysarobin possesses the inconvenience of staining the surrounding skin (temporarily) and permanently staining the clothing; and a number of substitutes- naphthol, resorcin, antarobin, hydroxylamin, etc.-have been proposed. Some of these are dangerous, while others are inefficient, and none of them are equal in efficacy to chrysarobin. This drug, however, should not be applied to the face or scalp, and we must instead use milder applications, such as tar or some of the essential oils, as the oleum pini sylvestris, oleum eucalypti, etc.

The following is an excellent aid:

Rx. Chrysarobin,

Acid Salicylici, aa gr. x.

Unquent Resinol, j.

Sig. Apply thoroughly at night and bathe thoroughly next morning, or, Rx. Tar,


Soft soap, aa 3j. M.

Sig. Apply locally, with the flannel or a coarse piece of cloth, and is firmly rubbed into the part night and morning according to the effect.

The following is a very good application for an ordinary case of psoriasis which is passing on to the chronic stage.

Melford Eugene Douglass
M.E.Douglass, MD, was a Lecturer of Dermatology in the Southern Homeopathic Medical College of Baltimore. He was the author of - Skin Diseases: Their Description, Etiology, Diagnosis and Treatment; Repertory of Tongue Symptoms; Characteristics of the Homoeopathic Materia Medica.