The prognosis is usually favorable, so far as concerns the immediate eruption, but as to recurrences, nothing positive can be stated. In rare instances, however, the cure remains permanent.
How is psoriasis treated?
Both constitutional and local remedies are demanded in most cases.
Do dietary measures exert any influence?
As a rule, no; but the food should be plain, and an excess of meat avoided.
Name the important constitutional remedies usually employed in psoriasis.
Arsenic is of first importance. It is not suitable in acute or markedly inflammatory types; but is most useful in the sluggish, chronic forms of the disease. The dose should never be pushed beyond slight physiological action. It may be given as arsenious acid in pill form, one-fiftieth to one-tenth of a grain three times daily, or as Fowler's solution, three to ten minims at a dose.
Alkalies, of which liquor potassæ is the most eligible. It is to be given in ten to twenty minim doses, largely diluted. It is valuable in robust, plethoric, rheumatic or gouty individuals with psoriasis of an acute or markedly inflammatory type; it is not to be given to debilitated or anæmic subjects.
Salicin, sodium salicylate, and salophen in moderately full doses act well in some cases. Occasionally thyroid preparations have a good effect.
Potassium Iodide, in doses of thirty to one hundred grains, t.d., acts favorably in some instances; there are no special indications pointing toward its selection, unless it be the existence of a gouty or rheumatic diathesis.