I received my medical degree from University College Cork of the National University of Ireland in 1980. After residency training in internal medicine in Cork and Dublin, I undertook Fellowship training and Allergy and Immunology at McMaster University in Canada, as well as serving as Chief Medical Resident. I followed this with a 3 year laboratory-based research Fellowship in the Department of Hematology Oncology at Tufts University-New England Medical Center. From 1991-2001, I was a staff physician in the Division of Allergy at that institution and Assistant Professor of Medicine at Tufts University. I co-directed the clinical practice and worked part-time in a private practice between 1996 and 2001.

In 2001, I was appointed Clinical Director of the allergy unit at Massachusetts General Hospital. In 2004, I assumed an additional role as Director of the Fellowship Program in Allergy and Immunology in the Division of Rheumatology, Allergy and Immunology. I am an Associate Professor of Medicine at Harvard Medical School.