Close-up of an 81 year old male patient using an autoinjector pen to inject adrenaline into his thigh. This is used for the emergency treatment of anaphylactic shock, a type of allergic reaction that can be fatal in minutes. Common allergens that can trigger anaphylaxis include nuts, seafood and wasp stings. The symptoms of anaphylaxis include local or systemic swelling, a drop in blood pressure, and breathing difficulties. People who are susceptible to such attacks should carry adrenaline with them.