Synonyms: Zona; Herpes zoster; Ignis sacer; Shingles.
Zoster is an acute, self-limited, probably specific infectious disease of the nervous system. An acute hemorrhagic inflammation attacks one or more ganglia of the sensory roots of the cranial or spinal nerves. Early symptoms include loss of appetite, slight fever, and neuralgic pains long the course of the diseased nerve. On the third or fourth day the rash appears as groups of vesicles upon a reddened base, situated in the skin region supplied by the affected nerve. The neuralgia sometimes subsides with the outbreak, though often it persists for several days.
There may be only one or as many as twenty groups, each composed of a few or many vesicles. They appear simultaneously and reach their maturity in three or four days, when they are about pea size, hemispherical, clear, tense and thick-walled; they seldom rupture spontaneously. Later the contents become turbid, rarely pussy, but occasionally hemorrhagic in one or two vesicles. They finally dry to thin yellowish or brownish crusts which fall off in a few days and leave temporarily pigmented spots. One attack of zoster seems to confer an immunity.