San Antonio-born, Dr. Diaz followed in his father’s footsteps, Jose A. Diaz, M.D., family practitioner, who had a successful medical practice on the south side of San Antonio for 30 years.

Dr. Diaz graduated from St. Mary’s University in San Antonio, with high honors and a B.S. in Biology. He received his medical degree from the University of Texas Medical Branch at Galveston, Texas. His internship and residency, as well as his fellowship in Allergy and Immunology, was completed at the University of South Florida College of Medicine. Since opening his private practice, Allergy, Asthma and Immunology Associates of South Texas in 1988, Dr. Diaz has served as clinical assistant professor in the Department of Internal Medicine at the University of Texas Health Science Center in San Antonio. He was appointed Co-Director of the Allergy/Clinic Immunology Fellowship training program and directed the program for several years.

In addition to his private practice, Dr. Diaz is the President and Medical Director of Allergy and Asthma Research Center, established in 1989. As Medical Director of the Research Center, Dr. Diaz says his patients benefit from access to new medicines and information not yet available to most physicians or patients. In Dr. Diaz’ free time, he enjoys physical fitness, competing in Iron Man competitions and spending time with family.

Dr. Karkhanis joined Allergy SA in 2014. Dr. Karkhanis is board certified in Internal Medicine and Allergy and Immunology. Dr. Karkhanis received her medical degree with honors from Seth G.S. Medical College and K.E.M. Hospital in Mumbai, India. She was engaged in research activities at the University of Pittsburgh, after which she completed her internship and residency in Internal Medicine at St. Luke’s-Roosevelt Hospital Center and Columbia University in New York, New York and her fellowship in Allergy and Immunology from Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis, Missouri.

She is an active participant in national allergy meetings, and has presented and published multiple reports. She is also an active member of the following organizations: American Academy of Allergy, Asthma, and Immunology, American College of Allergy, Asthma, and Immunology, Texas Medical Association, Texas Allergy, Asthma, and Immunology Society and San Antonio Allergy, Asthma, and Immunology Society. Dr. Karkhanis works with pediatric and adult patients to help treat allergies and asthma.

She also serves as a Sub-Investigator on several studies at the Allergy and Asthma Research Center, which keeps her abreast of the latest developments in the field. In her spare time, she enjoys art, literature, culinary experimentation and spending time with her family.

Raul Villarreal, M.D., a native Texan, did his undergraduate studies at Rice University in Houston and earned his medical degree from the University of Texas Southwestern in Dallas. He then completed his Internal Medicine Residency at McGaw Medical Center of Northwestern University in Chicago, IL, and his fellowship in Allergy and Immunology at the University of South Florida where he served as Chief Fellow during his final year. Dr. Villarreal is an active presenter at both regional and national allergy meetings and has been published in The Journal of Allergy and Clinical Immunology and Annals of Allergy, Asthma & Immunology. He served as sub-investigator in several food allergy, asthma, and eczema clinical research trials including studies on peanut oral immunotherapy and biological treatments for atopic conditions.

Dr. Raul Villarreal is fluent in English and Spanish and sees both pediatric and adult patients.

Erica Gomez, FNP-C, obtained her Master of Science in Nursing with a specialization in Family Nurse Practitioner at the University of Texas Health Science Center at San Antonio (UTHSCSA). Prior to that, she received her Bachelor of Science in Nursing also from UTHSCSA. Erica is certified by the American Association of Nurse Practitioners.

Ms. Gomez is a highly motivated individual who has advanced from medical assistant to registered nurse and, now, a family nurse practitioner. In her free time, she enjoys spending time with her family and friends.

Ms. Gomez is fluent in English and Spanish and sees both pediatric and adult patients.

Devon Elder, PA-C is a Texas native that received her Master of Physician Assistant Studies (MPAS) from the University of North Texas Health Science Center at Fort Worth. Prior to that, she earned a Bachelor of Science in Psychology with a minor in Biology from Baylor University.

She is an active member of the American Academy of Physician Assistants, the Texas Academy of Physician Assistants, and the Association of PAs in Allergy, Asthma, and Immunology. In her free time, she enjoys spending time with family and friends, hiking and growing different types of plants.

Ms. Elder is board certified and sees both pediatric and adult patients.

Kaitlyn Diaz PA-C, received her Master of Physician Assistant Studies (MPAS) from UT Health Science Center at San Antonio. Prior to that she earned her Bachelor of Science degree in Exercise Science with a minor in Psychology from Central Christian College of Kansas in McPherson, Kansas. While at Central Christian, she was a dual sport athlete and captain of the Women’s Soccer team. 

Ms. Diaz is an active member of the Bexar County Society of Physician Assistants, the American Academy of Physician Assistants, and the Association of PAs in Allergy, Asthma & Immunology. 

In her free time, she enjoys traveling, gardening, watching sports, and spending time with family, friends, and her labrador retriever. 

Ms. Diaz is board-certified and sees both pediatric and adult patients.