Our Team

When you become a patient of Oak Brook Allergists, you have our commitment to delivering the finest allergy and asthma care possible. You will be treated by highly qualified allergists and other healthcare providers who are specially trained in the treatment of allergic conditions. You will be informed, as fully as possible and in words you understand, about your treatment options, alternatives, limitations, and costs.

We promise to listen to your concerns. It is important to us that you feel comfortable enough to ask questions and discuss what’s important to you with us. Because we are a group practice, we encourage our patients to meet all of our providers. This helps us deliver the most comprehensive, appropriate medical care for you, without delay.

We understand our patients have busy schedules. Therefore, we offer convenience and flexibility with extended evening and Saturday hours, urgent cases seen within 24 hours, and four different offices throughout DuPage and Will counties: in Downers Grove, Elmhurst, Naperville, and Plainfield, Illinois. Your symptoms don’t wait until it’s convenient for you; that's why we at Oak Brook Allergists are always available when you need us.

Oak Brook Allergists was established in 1962 by Dr. Joseph Cece, a Chicago-area allergy specialist. At the time, he was the only practicing allergist in DuPage County. Dr. Harold Leichenko, a colleague of Dr. Cece’s from Michael Reese Hospital, joined the practice shortly thereafter.

Dr. David J. Knysak joined Oak Brook Allergists in 1988. A clinical instructor at University of Michigan Medical Center before he entered private practice, Dr. Knysak’s allergy, asthma, and immunology expertise has been instrumental in the continuing success of Oak Brook Allergists. This was never truer than after Dr. Cece passed away in 1992 and Dr. Leichenko retired in 2003.

Dr. Raymond M. Pongonis Jr. joined Oak Brook Allergists in 2014. As a leading expert in food allergies, with a strong interest in pediatric patients, he has ably rounded out the robust complement of allergy and asthma treatments we are able to provide our patients.

Today, Oak Brook Allergists has a total of four offices, located in the “collar counties” of Illinois, bordering Chicago’s Cook County. Our patients are able to receive all of the medical services we offer at each Oak Brook Allergists office, whether they visit the office in Downers Grove, Elmhurst, Naperville, or Plainfield.