Is it unusual to develop an allergy to eggs at age 17?

Egg allergy: All food allergies occur in children at a higher frequency than in adults however; food allergy can develop at any age. Food allergy can occur regardless of how many years it has been consumed prior to the first adverse reaction.

Unusual? Yes.: Impossible? No. By that age most egg allergy that generally appears in infancy has resolved. Food allergies that appear in late adolescence & adult life are typically triggered by peanuts, tree nuts, seeds and seafood. But in allergy, as in all medicine, we never say never.