What is the youngest age someone can be tested for allergies?

There are no age limits for allergy testing. Food allergy testing can be done in very young patients (months of age). Allergy testing for rhinitis or asthma (pollens, grasses, etc) is routinely done in somewhat older patients, but occasionally, testing for dog, cat, dust, and other in-door allergens is done in patients that are younger than 1 year of age.