Our team of food allergy specialists at New England Food Allergy Treatment Center is committed to provide excellent, evidence based, and compassionate care for patients.

We have been serving patients in our food allergy treatment centers throughout Connecticut, Massachusetts, New England, the East Coast and those traveling from outside the United States looking for effective food allergy desensitization programs.

If you have any questions for our team of board certified physicians or professional office staff, you can check out our frequently asked questions, or feel free to contact us.

Margaret A. Vallen, M.D.
Physician, FAAAAI and FACAAI

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 completed her residency in Internal Medicine, Chief Medical Resident year after her Internal Medicine residency, fellowships in Pulmonary and Critical Care medicine, and in Allergy and Clinical Immunology, all at the Boston University Medical Center. 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.  Vallen is on the staff of the South Shore Hospital. Dr. Vallen founded Vallen Allergy and Asthma in 2021.  She has previously been on staff at The Boston Medical Center and Beth Israel Deaconess Medical Center.  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. S he is on the Board of South Shore SNAP-South Shore Special Needs Athletic partnership.
Jeffrey M. Factor M.D.
Medical Director, FAAAAI and FACAAI

Dr. Jeffrey M. Factor is clinical professor of pediatrics at the University of Connecticut School of Medicine. He is the Division Head, Allergy and Immunology, at Connecticut Children’s Medical Center and Director of its Food Allergy Clinic.

Dr. Factor is a magna cum laude graduate of Brown University where he was elected Phi Beta Kappa. He completed his pediatric residency at The Albert Einstein College of Medicine and the Montefiore Medical Center in New York. His Allergy and Immunology Fellowship training was at The New York Hospital – Cornell Medical Center in New York.
Dr. Factor is board certified in allergy and clinical immunology, and was recertified in 2001. He is a Fellow of the American Academy of Allergy, Asthma and Immunology and the American College of Allergy, Asthma and Immunology. He has written articles on food allergies, asthma, and skin testing and is active in patient education and advocacy groups. He has served on the Executive Council of the New England Society of Allergy (President 2001-2002), is a member of the Connecticut Allergy and Immunology Society, and the Connecticut Chapter of the American Thoracic Society. Dr. Factor has volunteered his time at the American Lung Association’s Camp Treasure Chest summer camp for asthmatic children in Connecticut. He helped establish a hospital asthma management program at Middlesex Hospital in Middletown, Connecticut and lectures frequently about allergic conditions, in particular, asthma and food allergies. Dr. Factor has been recognized in the Best Doctors in America, Hartford Magazine’s “Top Doctors” and Connecticut Magazine’s “Top Physicians” and “Top Docs for Women.”Dr. Factor lives in Avon, Connecticut with his wife Susan and their three daughters.
Jason O. Lee, M.D.
Physician, FAAAAI and FACAAI

Dr. Jason Lee is a Clinical Instructor in the Department of Medicine at the University of Connecticut School of Medicine. Dr. Lee is board certified in internal medicine as well as allergy and clinical immunology.


Dr. Lee holds hospital privileges at Hartford Hospital, Connecticut Children’s Medical Center, Middlesex Hospital, and Saint Francis Hospital and Medical Center. Dr. Lee earned his medical degree from the University of Medicine and Dentistry of New Jersey. Following medical school, he trained in internal medicine at Mount Sinai Medical Center in New York. Dr. Lee completed his allergy and immunology fellowship at Mount Sinai Medical Center as well. Dr. Lee is a member of the American Academy of Allergy Asthma and Immunology, the American College of Allergy Asthma and Immunology, the New England Society of Allergy, the Hartford County Medical Association, and the Connecticut Allergy Society. Dr. Lee holds special interests in asthma, food allergy, and chronic sinusitis. Dr. Lee has been recognized by the Connecticut Magazine’s “Best Doctors.”
Morgan Denno, APRN

Board Certified Family Nurse Practitioner, American Nurses Credentialing Center.  She graduated magna cum laude with her Master of Science in Nursing Sacred Heart University and her Bachelor of Science in Nursing from Western Connecticut State University.  Morgan has been part of the NEFATC team since 2013.

Morgan has dedicated the last several years to working in Allergy and ENT. Affiliate with Mass Eye and Ear – Mass General Brigham, Department of Otolaryngology.  She lives in Quincy with her husband and Pomeranian, Stewie.
Louis Mendelson

In loving memory of Dr. Mendelson.


His love and dedication to NEFATC will never be forgotten.