Allergy symptoms, which depend on the substance involved, can affect your airways, sinuses and nasal passages, skin, and digestive system. Allergic reactions can range from mild to severe. In some severe cases, allergies can trigger a life-threatening reaction known as anaphylaxis. Hay fever, also called allergic rhinitis, can cause: Hay fever, 
Sneezing
Itching of the nose, eyes or roof of the mouth
Runny, stuffy nose
Watery, red or swollen eyes (conjunctivitis)
 A food allergy can cause: A food allergy 
Tingling in the mouth
Swelling of the lips, tongue, face or throat
Hives
Anaphylaxis
 An insect sting allergy can cause: An insect sting allergy 
A large area of swelling (edema) at the sting site
Itching or hives all over the body
Cough, chest tightness, wheezing or shortness of breath
Anaphylaxis
 A drug allergy can cause: A drug allergy 
Hives
Itchy skin
Rash
Facial swelling
Wheezing
Anaphylaxis
 Atopic dermatitis, an allergic skin condition also called eczema, can cause skin to: Atopic dermatitis, 
Itch
Redden
Flake or peel
 Anaphylaxis Some types of allergies, including allergies to foods and insect stings, can trigger a severe reaction known as anaphylaxis. A life-threatening medical emergency, anaphylaxis can cause you to go into shock. Signs and symptoms of anaphylaxis include: 
Loss of consciousness
A drop in blood pressure
Severe shortness of breath
Skin rash
Lightheadedness
A rapid, weak pulse
Nausea and vomiting
