A pre-existing condition in health insurance is any health condition that an individual has before enrolment in a health insurance plan.
Declaration of pre-existing conditions/ailments/illnesses is important as it will ensure the coverage of treatment of illness from day one & will also assist the insurance company in underwriting the policy before inception to cover any future costs of treatment. Undeclared conditions will not be covered by the insurer for the entire policy period and will be declared a violation of the insurance principle of utmost good faith.