Annular Syphiloderm. (After I.E. Atkinson.)
Describe the squamous papule of syphilis.
This tendency of the large-papular eruption to become scaly, when exhibited, is more or less common to all papules, and constitutes the squamous or papulo-squamous syphiloderm (improperly called psoriasis syphilitica). The papules become somewhat flattened and are covered with dry, grayish or dirty-gray, somewhat adherent scales. The scaling, as compared to that of psoriasis, is, as a rule, relatively slight. The eruption may be general, as usually the case in the earlier months of the disease, or it may appear as a relapse or a later manifestation, and be limited in extent.
As a limited eruption it is most frequently seen on the palms and soles—the palmar and plantar syphiloderm. Occurring on these parts it is often rebellious to treatment.
Maculo-papular syphiloderm.
How are you to distinguish the papulo-squamous syphiloderm from psoriasis?
In psoriasis the eruption is more inflammatory, and usually bright red; the scales whitish or pearl-colored and, as a rule, abundant. It is generally seen in greater profusion upon certain parts, as, for instance, the extensor surfaces, especially of the elbows and knees. It is not infrequently itchy, and, moreover, presents a different history.
In the syphilitic eruption some of the papules almost invariably remain perfectly free from any tendency to scale formation; there is distinct deposit or infiltration, and the lesions are of a dark, sluggish red or ham tint; and, moreover, concomitant symptoms of syphilis are usually present.