prodromic
/ˌprɒˈdrɒmɪk/ or /ˌproʊˈdrɒmɪk/Definitions
1. adjective
relating to or resembling a prodrome; being an early sign or symptom of an illness or disease, especially one that precedes a more severe episode or attack.
“The prodromic symptoms of the disease include fever and muscle aches, which can last for several days before the full-blown illness sets in.”
2. noun
a prodrome; an early sign or symptom of an illness or disease.
“The doctor warned that the prodromic symptoms of the flu were often mild at first, but could quickly escalate into a severe illness.”