If something is symptomatic, it shows the signs of a particular illness or problem.
The word symptomatic is often used in medical or scientific situations to describe when something shows the signs of a sickness or issue.
Examples:
His cough is symptomatic of a cold.
The red spots on her skin are symptomatic of chickenpox.
The high fever is symptomatic of the flu.
The runny nose is symptomatic of allergies.
The loud sneezing is symptomatic of a cold.
Her tiredness is symptomatic of staying up too late.