Our Providers


Board Certified Allergy And Asthma Specialists (For Children & Adults)


Margaret Vallen headshot

Dr. Vallen is a magna cum laude graduate of Gettysburg College where she was elected Phi Beta Kappa. She earned her medical degree from the Medical College of Pennsylvania, now Drexel Medical School.

She is certified by the American Board of Internal Medicine with subspecialty certification in Pulmonary and Critical Care, and she is certified by the American Board of Allergy and Immunology and was recertified in 2013. She was elected into Alpha Omega Alpha Medical Honor Society at the end of her Chief Medical Residency. Dr. Vallen is a Fellow of the American Academy of Allergy, Asthma & Immunology, a Fellow of the American College of Allergy, Asthma & Immunology, and a Fellow of the College of Chest Physicians. She is a member of the Massachusetts Medical Society, the American Thoracic Society, and the New England Society of Allergy.

She is the mother of twins and resides with her husband on the South Shore, Massachusetts. She is a medical advisor for SAFE ,South Shore Allergy Families Educating, and on the Board of South Shore SNAP-South Shore Special Needs Athletic partnership.

Learn more about Dr. Vallen and the value she provides patients by watching this video.

Morgan Denno, MSN APRN

Board Certified Family Nurse Practitioner
Morgan Denno headshot

Morgan is a Board Certified Family Nurse Practitioner. Morgan received her BSN from Western Connecticut State University and her MSN from Sacred Heart University. She began her clinical practice as an APRN in 2017 and has been working in allergy since 2013. Prior to joining Vallen Allergy and Asthma in January 2021 she worked in Pediatric ENT at CT Children’s Hospital and continues to work at New England Food Allergy Treatment Center overseeing patients undergoing immunotherapy and oral food challenges.