Dr. Hartog earned his medical degree from Medical College of Wisconsin in Milwaukee. He completed his internal medicine residency at University of Iowa Hospitals and Clinics in Iowa City and his allergy and immunology fellowship at Washington University School of Medicine in St. Louis. Dr. Hartog's clinical interests include primary immunodeficiency, allergic eye disease, environmental allergies (seasonal and year-round), chronic sinusitis, nasal polyps, allergen immunotherapy, eczema, food and drug allergies, asthma, hives and swelling, contact dermatitis, anaphylaxis, eosinophilic disorders (especially eosinophilic esophagitis and hypereosinophilia) and mast cell disorders (especially mastocytosis).