What are some common allergy symptoms?

Allergy symptoms include sneezing, runny nose, itching skin and swelling of the face, tongue and lips, states Mayo Clinic. Types of allergies include insect stings, allergies to foods, hay fever and drug allergies.

Symptoms of allergy can involve the skin, airways, the digestive system and nasal passages, reports Mayo Clinic. In severe cases, allergies can cause anaphylaxis, which is a reaction that can cause severe shortness of breath, a drop in blood pressure, skin rash and loss of consciousness.

Allergies occur when the immune system mistakenly produces antibodies against a normally harmless substance, releasing histamine, notes Mayo Clinic. Common allergy triggers include medications, such as penicillin; foods, such as shellfish, tree nuts and milk; and airborne allergens, such as pollen and dust mites.