Meet Our Specialists

Andrew C. Engler, M.D.

Andrew C. Engler, M.D. is the medical director of The Allergy and Asthma Clinic in San Mateo, California.

Dr. Engler received his Bachelor of Art degree, with distinction, from Stanford University in 1978. He was elected to the Phi Beta Kappa society when he was still a junior in college. After 2 years as a medical student at Yale, he returned to Stanford where he received his M.D. degree in 1982. He went on to complete his internship and residency at Stanford University Hospital and is Board Certified in Internal Medicine. Dr. Engler then received several years of additional training in Allergy, Asthma and Immunology. He founded The Allergy Clinic in San Mateo in 1987.

June Zhang, M.D.

Dr. Zhang grew up in Seattle and received her MD degree from the Medical College of Wisconsin. She completed her pediatrics residency at Children's Hospital of Oakland in 2006 and her allergy and immunology fellowship at the Children's Hospital of Pittsburgh and University of Pittsburgh Medical Center in Pennsylvania in 2008. She started her career in private practice with Allergy, Asthma & Immunology Associates in Dallas, Texas where she also was a clinical instructor of Allergy/Immunology at the Children's Medical Center of Dallas, University of Texas Southwestern Medical Center.

Hana Tartibi, M.D.

Dr. Tartibi grew up in Dallas, Texas as the oldest of three siblings.  She received her medical degree at University of Texas Southwestern Medical Center.  She remained at UT Southwestern and Parkland Hospital for her Internal Medicine residency, which she completed in 2012.  She completed her Allergy/Immunology fellowship at Louisiana State University Health Sciences Center in Shreveport.  She returned to the Dallas area to start her career as an allergist.  Dr. Tartibi is Board Certified both in Internal Medicine and Allergy/Immunology.  She is also a member of the American Academy of Allergy, Asthma and Immunology and the American College of Allergy, Asthma and Immunology.


Our Nurse Practitioners

Brooke Leon, N.P.

Brooke Leon earned her Bachelor’s degree in Health Sciences with a minor in American Sign Language from California State University East Bay in June of 1994. She then received her Bachelor’s degree in Nursing in May of 1996 and achieved her Master’s Degree in Nursing as a Family Nurse Practitioner at the University of San Francisco in May of 2000. While completing her Master’s degree, she was employed as a registered nurse at the Allergy and Asthma Clinic where she was able to work closely with our medical director, Dr. Engler. During this time, she had the opportunity to assist in the management of patients and help provide ongoing care and education to patients with acute and chronic allergic diseases. As a board certified Nurse Practitioner, she is a member of the Sigma Theta Tau Nursing Honor Society and is a frequent lecturer on the subject of allergy and asthma. She has provided a number of educational seminars to many health care professionals in the community, as well as in other cities on the West Coast.

When she is not taking care of patients, Brooke enjoys exercising, baking and cooking. She also loves to participate in outdoor activities and travel with her husband and 2 children.

Elisabeth Denker, N.P.

Elisabeth Denker earned her Bachelor’s Degree in Science and Nursing from Columbia University in New York City. She also completed her Master’s Degree in Nursing in the Family Nurse Practitioner Program at Columbia University. She achieved a Bachelor’s degree in Sociology and a Minor in Art History and Gender Studies from Santa Clara University. She is certified by the American Academy of Nurse Practitioners and she is a member of both the Sigma Theta Tau Nursing Honor Society and the Phi Beta Kappa Honor Society. When she is not taking care of patients, Elisabeth enjoys all winter and water sports, especially scuba diving. She also loves to cook and travel.