Allergy and Asthma Clinic
DIPLOMATE, AMERICAN BOARD OF ALLERGY ANO IMMUNOLOGY
CLINICAL ASSOCIATE PROFESSOR, UT HEALTH SCIENCE CENTER AT SAN ANTONIO
March 16, 2026
Dear Patient,
It is with mixed emotions that I announce my retirement effective April 20, 2026. Caring for you, my patients, has been the most rewarding part of my 44-year career with McKenna Allergy and Asthma Clinic.
I have come to know many of my patients and their families as friends, and I am honored that many of you have asked me to care for two, and even three, generations.
As I transition to a new chapter in my life, your medical care will continue uninterrupted by Rigoberto Garza, MD and Cleo Pena, PA at McKenna Allergy and Asthma Clinic. Dr. Garza joined our practice four years ago and is a knowledgeable and caring physician. Cleo Pena, PA has practiced alongside me for over ten years and provides quality, compassionate care.
Dr. Garza is Board Certified in both Internal Medicine and Allergy and Immunology. He graduated from the University of Texas and received his Medical Degree from University of Texas Medical Branch in Galveston where he completed his residency in Internal Medicine and fellowship in Allergy and Immunology. His approach to allergy and asthma management is similar to mine and I trust he will take great care of you and your family. You will also continue to see the same familiar faces that provide experienced clinical and support services to the physicians and our patients.
Should you desire to transition your care to another physician, please contact the McKenna Allergy and Asthma Clinic. As the custodian of your medical records, we can provide copies to you or another physician. If you have questions or concerns, please do not hesitate to contact us at 956-425-9240.
Thank you for your trust in me and Mckenna Allergy and Asthma Clinic's excellent team for your medical care. I wish for you the best in health and life.
Sincerely,
William R. McKenna, MD
1713 Treasure Hills Blvd., Suite 1-B, Harlingen, Texas 78550
(956) 425-9240 in Harlingen• (956) 687-2111 in McAllen• (956) 541-1561 in Brownsville
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MCKENNA ALLERGY & ASTHMA CLINIC IS COMMITTED TO THE HEALTH AND WELL BEING OF OUR PATIENTS. DUE TO THE COVID-19 PANDEMIC ….. APPOINTMENTS ARE REQUIRED FOR ALL VISITS AND ALLERGY SHOTS. We will be closed the week of December 26. Normal operation hours will resume Monday, January 2, 2023. ****NO EXCEPTIONS****