Physicians

Larry S. Posner, MD

Larry S. Posner, MD

Dr. Larry Posner, MD is the founder and principal at North Bay Allergy and Asthma Medical Associates. Dr. Posner attended medical school at the University of Southern California, and then completed his pediatric residency at the University of California, Irvine, before completing his fellowship training in Allergy and Immunology at the University of California, San Francisco (UCSF).

Dr. Posner is Associate Clinical Professor of Pediatrics at UCSF and Adjunct Clinical Professor of Allergy and Immunology at Tuoro University in Vallejo, California.

Besides running a clinical practice for the past 27 years, Dr. Posner is also founder of North Bay Clinical Trials, and has participated in over 40 clinical research studies over the past 15 years. He currently serves as immediate past president of the Western Society of Allergy, Asthma and Immunology. His former leadership positions include Chief of Staff at Queen of the Valley Medical Center, specialty delegate to the California Medical Association, President of the Northern California Allergy Association and executive board director of the California Society of Allergy, Asthma and Immunology. He is a founding director for Napa County Asthma Coalition and has served on the board of directors for the local American Lung Association Chapter.

In 2006, he co-founded West Coast Allergy and Asthma Network. Dr. Posner’s major interests are the treatment of pediatric asthma and food allergy, and he has served on the scientific advisory board for Mylan pharmaceuticals and for Astra Zeneca.

Christopher Chang, MD, PhD, MBA

Christopher Chang, MD, PhD, MBA

Dr. Christopher Chang, MD, PhD trained in Allergy and Immunology at the University of California, Davis. Prior to that, he received his MSc in Chemistry as well as his PhD and MD all from Georgetown University in Washington, DC.

He completed his pediatric residency at Children’s Hospital of Los Angeles and subsequently conducted research in Kawasaki Disease at the University of Hong Kong.

He is former Chief of Allergy and Immunology and Director of the Allergy and Immunology Fellowship Program at TJU in Philadelphia, and is currently Clinical Professor of Medicine and the Associated Director for the Allergy and Immunology Fellowship at UC Davis.

Dr. Chang has published extensively on topics ranging from asthma to autoimmune diseases, with over 100 publications in national and international journals and various textbooks. He is the founder of the International Association of Chinese Allergists, Immunologists and Dermatologists (IACAID), and is the Editor-in-Chief of Integrative Medicine Insights. Dr. Chang is also an experienced researcher, and conducts clinical trials with Dr. Posner for North Bay Clinical Trials. Dr. Chang has served on the scientific advisory board for Baxter (now Baxalta), and he has a special interest in immunodeficiency diseases and autoimmunity.

Sam Ahn, MD

Sam Ahn, MD

Sam Ahn,  MD joined North Bay Allergy & Asthma Associates in August 2017.  Dr. Ahn has trained at some of the most elite institutions in the United States.  He graduated from John Hopkins University with a degree in Biology.  He then received his MD from Harvard Medical School and completed his Internal Medicine Residency at Yale in Connecticut.  He completed his Allergy & Immunology Fellowship at Mount Sinai Medical Center in New York City.  During his fellowship, he authored several abstracts and scientific papers relating to both food allergies as well as Common Variable Immune Deficiency (CVID).

Prior to joining North Bay Allergy and Asthma Associates, Dr. Ahn practiced in Phoenix, Arizona for 7 years.  While there, he was the Vice President of the Arizona Allergy & Asthma Society.  He received numerous accolades, including “America’s Top Physician” several years.  Other awards include Patient’s Choice Award, Compassionate Doctor Award and Castle Connolly’s Top Doctor Award.  Most recently, he received the Top 1% of Professionals award.  Dr. Ahn has a special interest in volunteering his medical services throughout his career and has volunteered in medical clinics in various countries in Africa, as well as refugee clinics and free clinics here in the US.

He was raised in the New York City area but has family in the Bay Area. Joining him in the move to Napa are his wife Michelle and young son Davis. Outside of medicine, his other interests include music, art, traveling and his three dogs.

Hours

Monday - 9:00 am - 5:00 pm

Tuesday - 9:00 am - 5:00 pm

Wednesday - 9:00 am - 7:00 pm

Thursday - 9:00 am - 5:00 pm

Friday - 9:00 am - 12:00 pm

Napa Allergy Shot Hours

Monday - 9:00am - 12:00pm; 2:00pm - 6:00pm

Tuesday - 9:00 am - 12:00pm

Wednesday - 2:00 pm - 7:30 pm

Thursday - 2:00 pm - 6:00 pm

Friday - 9:00 am - 12:00 pm

Sonoma Allergy Shot Hours

Monday - Closed

Tuesday - 9:00am - 12:30pm; 2:00pm - 5:30pm

Wednesday - Closed

Thursday - 2:00 pm - 6:00 pm

Friday - Closed