Global Food Allergy Market Assessment, By Allergen Source [Gluten, Peanut, Mustard, Milk, Egg, Fish, Others], By Diagnosis [Blood Test, Skin-prick Tests, Others], By Treatment [Antihistamines, Adrenaline, Oral Immunotherapy, Others], By End-user [Hospitals, Specialty Clinics, Others], By Region, Opportunities and Forecast, 2017-2031F