This mechanism is so sensitive that unbelievably small quantities of the allergen can cause a reaction. The released chemicals act on blood vessels to cause the swelling and low blood pressure, and on the lungs to cause asthma. Severe allergic reactions to fresh fruit are also sometimes reported. In some individuals, exercise can trigger a reaction - either on its own, or in combination with other factors such as ingestion of a particular food. Nobody would necessarily experience all of these symptoms.
Some people find that the symptoms they experience are always mild.
For example, there may be a tingling or itching in the mouth - nothing more. This is not serious in itself, and may be treated with oral antihistamines. Nevertheless, it is wise in all cases to make an appointment with the doctor and seek a referral to a specialist allergy clinic. A bad allergic reaction in the past puts a person at a risk for a severe reaction in the future. You should see your GP and insist on a referral to a specialist allergy clinic.