The following information is from the District of Columbia (DC) state board of education regarding differences between an Individualized Education Program (IEP) and a 504 plan for a disabled student. This document can provide some beginning guidance for parents of children with Lyme disease as a basis for what schools may need to provide. Different states can have additional safeguards.
In addition, see article by Alfred C. Tagliabue, M. Ed., Director of Student Personnel and Community Services, Jackson Township, New Jersey (Retired):
504, IDEA & IEPs: I know what my child needs to be successful in school, but what are these numbers and letters all about?