The patch of eruption is made up of several concentric rings. Difference of duration of the individual rings, usually slight, tends to give the patch variegated coloration; as, for example, in erythema iris and herpes iris.
What meaning is conveyed by the term “marginate”?
The sheet of eruption is sharply defined against the healthy skin; as, for example, in erythema marginatum, eczema marginatum.
What meaning is conveyed by the qualifying term “circumscribed”?
The term is applied to small, usually more or less rounded, patches, when sharply defined; as, for example, the typical patches of psoriasis.
When is the qualifying term “gyrate” employed?
When the patches arrange themselves in an irregular winding or festoon-like manner; as, for instance, in some cases of psoriasis. It results, usually, from the coalescence of several rings, the eruption disappearing at the points of contact.
When is an eruption said to be serpiginous?
When the eruption spreads at the border, clearing up at the older part; as, for instance, in the serpiginous syphiloderm.