“I strive to provide the highest quality care for all my patients by taking the time to listen and address all of their concerns, educating them about their conditions, and delivering evidence-based care.”

Board Certifications

  • Allergy & Immunology
  • Internal Medicine

Areas of Expertise

  • Allergic Rhinitis
  • Asthma
  • Drug Allergy
  • Eczema
  • Food Allergy



University of Texas Southwestern Medical Center
Allergy and Immunology
Dallas, TX


Virginia Commonwealth University
Internal Medicine
Richmond, VA


Northwestern University
Internal Medicine
Chicago, IL

Medical School

Virginia Commonwealth University School of Medicine
Doctor of Medicine
Richmond, VA

Undergraduate School

Duke University
Bachelor of Arts in Chemistry
Durham, NC

Hospitals Affiliated With

Holy Cross Germantown Hospital
Shady Grove Adventist Hospital


“Identification of peanuts, and tree nuts: are allergists smarter than their patients?” Annals of Allergy, Asthma & Immunology, (2013); 111(4):282-5.

“Misdiagnosed food allergy resulting in severe malnutrition in an infant” Pediatrics, (2013); 132(1):e229-32.

“Adverse reactions during drug challenges: a single US institution’s experience” Annals of Allergy, Asthma & Immunology, (2013); 110(2):86-91.e1.

Professional Associations

American Academy of Allergy, Asthma, and Immunology
2010 – Present

American College of Allergy, Asthma, and Immunology
2010 – Present

Greater Washington Asthma, Allergy & Immunology Society
2013 – Present

Montgomery County Medical Society
2012 – Present

Personal Interests

Dr. Kao lives in Gaithersburg and is an accomplished pianist. He also enjoys running, hiking, playing tennis, and traveling.


Leon Kao, MD is board certified in both Allergy and Immunology and Internal Medicine. He graduated Cum Laude from Duke University with a B.A. degree in chemistry. He graduated with an M.D. from Virginia Commonwealth University School of Medicine where he was inducted into the Alpha Omega Alpha Honor Medical Society. Dr. Kao completed his Internal Medicine internship at Northwestern University in Chicago and went on to complete his residency at Virginia Commonwealth University. After working as a hospitalist for a year in Richmond, Virginia, Dr. Kao completed his Allergy and Immunology fellowship at the University of Texas Southwestern in Dallas. During his allergy and immunology fellowship, Dr. Kao presented his research at national allergy meetings. His research on drug allergies is published in the Annals of Allergy, Asthma, and Immunology, and he has co-authored a case report on food allergies in Pediatrics.