Groups 9 and 10 are characterized by the presence of red scaling lesions. The scaling, which differentiates these two groups from groups 7 and 8, may or may not be readily apparent. Three types of scale must be sought . Psoriatic-type scale (large white or gray flakes) can be easily seen, but pityriasis-type scale is fine and powdery. One needs to scrape it with the edge of scalpel blade before the fine white powder becomes visible. Lichen-type scale is tightly compacted on the surface of the lesion. Its flatness and tight attachment give it a shiny, translucent appearance.

In addition, some lesions that are by nature scaly may have bee modified by the patient in such a way that no evidence of scale can be found. Thus if the patient has vigorously bathed shortly before the examination, if the patient has applied any hand cream or lubricant, or if the patient’s disease is partially treated, no scale may be discernible. For this reason, patients will red lesions should be asked whether or not they had previously noted any scaliness or roughness.

Differentiation between the lesions of groups 9 and 10 depends primarily on the presence (the eczematous diseases) or absence (the papulosquamous diseases) of epithelial disruption. A secondary point in diffirentiation between these two groups depends on margination. Papulosquamous lesions tend to be sharply marginated around the entire periphery, whereas eczematous lesions will have at least a portion of the circumference that is poorly marginated.