# Skin Diseases of Children/Psoriasis

Plate IV.
Psoriasis
From the collection of photographs of
Dr. George Henry Fox.
PSORIASIS.
Psoriasis, though most frequently met with after the age of puberty, is by no means a rare affection in childhood and may even occur in infancy. Though different cases present a notable variation in their clinical appearance, the characteristic features of the disease are very much the same at all ages. The eruption is always dry and scaly, whatever may be the age of the patient, but in childhood it is not generally so well developed and so extensive as it is apt to be in later years.
Psoriasis begins in the form of one or more red points, which quickly become covered with white, silvery scales (Fig. 13). These may be readily scratched off by the finger nail, and when this is done a bleeding surface is exposed. When many of these small, scaly lesions are present the eruption is described as punctate psoriasis, and this form of the eruption is comparatively more frequent in children than in adults; when the scaly lesions increase in size and appear like drops of grease or thin mortar spattered over the skin, we have the guttate form of the disease (Fig. 14); and when the patches assume the size and shape of silver coins they are often described as nummular psoriasis (Fig. 15). By healing in the centre these lesions may be converted into scaly rings, or by peripheral increase and coalescence they may result in the formation of extensive scaly patches (Fig. IG). Diffused or general psoriasis is, however, rarely met with among children.
The amount of scaliness present in any case depends upon the attention which the patient naturally devotes to his skin. If baths are frequently taken, and especially if any fat or oil is rubbed over the patches, the scales are generally absent and the eruption presents a tolerably smooth, reddened appearance. When no attention is paid to the care of the skin, the scales often accumulate upon the psoriatic patches until they are very prominent and present a silvery-white or dirty-yellow appear​ance. As the eruption tends to disappear the scaling grows less, often disappearing from the centre of the patch and leaving a marginate ring. Finally the redness fades and the skin assumes a normal appearance, except in certain cases where pigmentation may occur.
In rare cases of psoriasis the eruption may tend to rapidly involve the whole skin. The cutaneous congestion is severe, and large flakes of partly detached epidermis may take the place of the silvery scales. In other words, an attack of acute
Fig. 13.—Punctate lesions covered with white scales.
dermatitis exfoliativa has set in and complicated and obscured the psoriasis. When the dermatitis has subsided the psoriasis is very apt to reappear.
Psoriasis is not only a dry and scaly eruption, but it is invariably marginate. Whether occurring in small discs or in large, irregular patches, the border is always sharply defined and never shades off gradually into the surrounding healthy skin, as does the ordinary patch of eczema. This is a diagnostic point of great importance. In many cases of eczema the ​patches may be dry and scaly, and present a resemblance to those of psoriasis, but the rounded, silvery discs or larger marginate patches of the latter disease are usually so characteristic that an error in diagnosis is not likely to be made.
The localization of the eruption is another important diagnostic point. While eczema may appear upon almost any part of
Fig. 14.—Guttate lesions with scales washed off.
the body, and often exhibits a tendency to attack the flexor aspect of the joints and other parts where the skin is thin and delicate, psoriasis is commonly seen upon the extensor surface of the extremities and is especially apt to be noted about the elbows and knees. Upon the scalp the two affections often present a strong resemblance, but in psoriasis the scaly patches ​are apt to be small, numerous, and circular, with healthy skin intervening, while eczema of the scalp usually occurs in one large, diffused patch.
The symmetry of the eruption in psoriasis is also a characteristic feature. The eruption upon one extremity or one side
Fig. 15.—Nummular and circinate psoriasis.
of the trunk is usually duplicated upon the other side, while eczema is very frequently unilateral.
The papular syphilide often assumes a squamous form and presents for a time a strong resemblance to psoriasis. Fortunately it is rarely met with in childhood, but at any age it ​differs from psoriasis in one respect. While in the latter affection the infiltration of the skin is slight and the accumulation of scales a prominent feature, in the papular syphilide the infiltration of the skin is considerable and the scaling is comparatively slight.
It is a noteworthy fact that many patients suffering from
Fig. 16.—Patches healing in centre, enlarging and coalescing.
psoriasis are unusually well developed and robust in appearance. It is not, like eczema and certain other skin affections, a disease of the weak and the neglected, but one which seems to delight in attacking those who are strong and well nourished. In any case, however, where the tendency to psoriasis exists, the eruption is certain to be most severe whenever the patient is weakened by lack of proper food or by overwork.
​ The tendency to psoriasis is frequently inherited, and often the disease may bo observed in two or more generations. Not infrequently it shows a tendency to skip a generation, and it has been claimed that psoriatic subjects are the offspring of eczematous, dyspeptic, asthmatic, gouty and rheumatic, as well as of psoriatic parents. External irritation only produces the disease in those who manifest a predisposition to it.
While it is often an easy matter to remove the eruption by treatment, it is difficult, if not impossible, in many cases, to prevent its speedy return. The eruption shows a marked tendency to relapse or to increase in severity in the spring or at some particular season, and in many cases persists for years or even throughout a lifetime. It often improves or disappears spontaneously for a few months or even for a year or more, and then reappears and continues its fluctuating course. The prognosis, therefore, is always a grave one as regards the permanent cure of the disease; but, in spite of the fact that some have declared psoriasis to be incurable, there are many cases which get well and remain well.
In the treatment of psoriasis a host of remedies have been employed, and many of them owe their repute to the fact, already stated, that the eruption tends at times to disappear spontaneously, and to any remedy employed at such a time the credit of a cure would naturally be awarded.
Among internal remedies, arsenic is the one most commonly employed and probably the most efficacious. In many cases, however, it may do much more harm than good. When the skin is irritable and the psoriatic patches congested, arsenic is worse than useless and alkaline diuretics are greatly to be preferred. But, on the other hand, when the disease is tending to get well, the administration of arsenic will often produce a most brilliant therapeutic result.
Of the various local remedies employed, chrysarobin stands without a rival. In many cases it produces a speedy and brilliant result which can be attained by no other local application. It has serious objections, however, which often forbid its use. When the skin is irritable it may cause the eruption to spread. Like arsenic, it is most likely to do good when the acute congestion of the psoriatic patches has subsided and the eruption is tending toward a spontaneous improvement. It not only stains the skin temporarily — which, however, is a matter of little importance — but it permanently discolors the underclothing and the bed linen, if due precaution is not taken. When ​rubbed in where the skin is thin, or near it, as, for example, the axillae and flexures of the joints, it often excites a very unpleasant dermatitis for a few days; and when by chance a little of the ointment gets into the eye a very severe conjunctivitis often results. This chance is somewhat lessened by applying the drug in the form of a varnish composed of gutta-percha solution or collodion, but then its therapeutic effect is decidedly lessened. Upon the trunk and extremities a five or ten per cent ointment, made by rubbing up finely sifted chrysarobin in vaseline, can be advantageously used; but upon the scalp and face the ointment of ammoniated mercury will generally prove efficacious, and is to be preferred to the chrysarobin.
Prolonged baths are often of service in macerating the scaly patches, and, when the skin is not too irritable, soap frictions are valuable in removing the scales and preparing the skin for inunction. In many cases, however, owing to the intense congestion of the affected skin, a hot bran or alkaline bath will prove more agreeable than the use of soap.