Arizona's First & Premier Allergy Asthma Practice

About Our Practice


Saving you money on tissues and eyedrops since 1969.

Established in 1969, Allergy Asthma Clinic is Arizona’s first and foremost medical practice dedicated solely to the diagnosis and treatment of asthma, allergy and immunodeficiency. Serving the Valley for over forty years, our award winning team of physicians and nurses works closely with each patient to provide the most up-to-date diagnostics and individualized treatments.

Our doctors and staff are not only at the top of their medical field, but are also committed to improving the lives of those who suffer from allergies and asthma. All of our allergy specialists are board certified and involved in the education of medical students and residents. 

This commitment has helped us become one of the nation's leading centers for the diagnosis and treatment of asthma, allergy and immunodeficiency.

chris couch headshot
Mark Schubert

Bart Leyko, M.D.
Diplomate, American Board of Allergy and Immunology
Diplomate, American Board of Internal Medicine  

Dr. Leyko was born and raised in Poland. He obtained his degree in Biology at University of California, Riverside. He attended Jagiellonian University, College of Medicine in Krakow, Poland, followed by internal medicine training at Michigan State University. He completed his Allergy and Immunology fellowship in State University of New York at Stony Brook.

Dr. Leyko conducted clinical research during his fellowship and authored several abstracts and articles. He is currently a medical director of Allergy Asthma Clinic and a Clinical Assistant Professor at the University of Arizona, College of Medicine. He is actively involved in education of medical students, residents and the community. His dedication to his patients earned him a multitude of awards including Patient's Choice, Most Compassionate Doctor, Super Doctor and America's Top Physician.

Dr. Leyko is married and enjoys coaching sports to his two sons. In his free time he likes to ride his mountain bike, compose music and travel.

Chris Couch, M.D.

Diplomate, American Board of Allergy and Immunology
Diplomate, American Board of Pediatrics 

Dr. Couch was born and raised in Portland, Oregon. He completed his B.S. degree in Physiology and Developmental Biology at Brigham Young University. He obtained his M.D. degree from The University of Arizona College of Medicine Phoenix, and then completed his residency training in Pediatrics through the University of Nevada School Of Medicine in Las Vegas. Following residency training, Dr. Couch completed his fellowship in Allergy and Clinical Immunology at the University of Michigan in Ann Arbor.

Dr. Couch has authored several abstracts and publications in the field, with research interests in food allergy, asthma, and immune deficiency. He is a Clinical Assistant Professor at The University of Arizona College of Medicine Phoenix.

Dr. Couch and his wife are the parents of two children. He enjoys hiking, snowboarding, cycling, rock climbing and spending time with family.


Sherri Crespin, FNP-C.

Sherri Crespin is our certified Family Nurse Practitioner. She earned her Bachelor’s and Master‘s of Science in Nursing from the University of Texas at Austin. She graduated with honors and was inducted into the Golden Key National Honor Society, Sigma Theta Tau International Honor Society for Nurses, and was recognized as a Helen Fuld Scholar.

Her medical experience as a RN includes specialties of Emergency Medicine, Critical Care Medicine, Trauma Medicine and Hemodialysis. As a Nurse Practitioner her experience encompasses specialties of Internal Medicine, Dermatology and Allergy/Immunology.

Sherri is a Veteran of the US Army and was assigned to a Combat Support Hospital in Phoenix as well as serving with the Texas National Guard.

This is her second term as the President of the Dermatology Nurses Association; Phoenix Chapter and she is affiliated with The American Nurses Association, Arizona Coalition of Nurse Practitioners, Coalition of Advanced Practice Nurses and The Arizona Allergy Asthma Society.

In her free-time she enjoys hiking with her dogs, golf, tennis, Salsa-dancing and yoga.

Mark S. Schubert, M.D., Ph.D. Status Emeritus
Diplomate, American Board of Allergy and Immunology
Diplomate, American Board of Internal Medicine  

Dr. Schubert was born and raised in Phoenix, AZ. He graduated from Arizona State University with a B.S. in Microbiology, then obtained both MD and PhD degrees from the University of Arizona School of Medicine in Tucson. His PhD is in Molecular Biology with research in immunology. He completed his Internal Medicine Residency in the Good Samaritan/Phoenix VA Integrated Internal Medicine Residency Program, then completed his Subspecialty/Fellowship training in Allergy and Immunology at Stanford University School of Medicine.

Since 1989, Dr. Schubert has been in private practice in Adult and Pediatric Allergy, Asthma and Immunology here at the Allergy Asthma Clinic, Ltd. in Phoenix, AZ. He has been a recipient of the Phoenix Magazine “Best Doctors” 22 times and “Best Doctors in America” 13 times, amongst other national rankings. He is also a Clinical Associate Professor of Medicine at the University of Arizona College of Medicine. He has authored over 40 abstracts and publications in the field, including book chapters, and lectured throughout the country. His recent research interests have focused on chronic allergic inflammatory respiratory disorders.

Dr. Schubert and his wife Mary have two great kids that make him proud every day. His other interests include science in any area, music, history, classic novels, classic film, comedy, exercise, rose gardening (and growing things in general); he'd like to say golf, but notes that it hasn’t worked out too well.