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recrudescence

noun

breaking out afresh or into renewed activity; revival or reappearance in active existence.

1707, “a becoming raw again, a breaking out afresh,” from stem of Latin recrudescere “re-open” (of wounds), literally “become raw again,” from re- “again” (see re-) + crudescere, from crudus “raw” (see crude (adj.)) + inchoative suffix -escere. Meaning “revival” is from 1906. Related: Recrudescency (1650s); recrudescent (1726).

A recurrence of a pathological process or its symptoms after a period of improvement or quiescence.