What are the symptoms of allergy. For skin allergy or allergy of other systems, the main symptoms can be as follows: skin erythema, wheals, papules, blisters, etc., accompanied by varying degrees of itching. If it is a serious allergy, it can also cause laryngeal edema, dysphagia, dyspnea, and even anaphylactic shock. If allergy affects the gastrointestinal system, it may also cause gastrointestinal spasm and abdominal pain. Therefore, there are many manifestations of allergy, which can affect all systems. Please go to the hospital specifically to determine whether it is allergic.