Illinois Dermatology Institute: Illinois Dermatology Institute (IDI) is a partnership of renowned Dermatologists and Plastic Surgeons specializing in medical, cosmetic, and surgical Dermatology. With our patient-focused culture and collaborative approach, we have been able to expand, not just geographically, but to other specialties-allowing us to provide the excellent and compassionate care that we're known.With locations expanding across Illinois and Indiana, IDI is proud to be a part of Chicago's rich history for nearly 35 years.