A seven-year-old girl, weighing 30kg, has a history of asthma, allergic rhinitis and tree nut allergy. She is at a school carnival and, while playing tag, develops a persistent cough and coryza. She ate a brownie 30 minutes earlier. Her parents interpret her symptoms as a flare of her allergic rhinitis and asthma. 

They treat her with 10mg promethazine and, as per her asthma action plan, give her 30mg prednisone and 12 puffs salbutamol via a spacer. Following this, she vomits and becomes drowsy. On walking to the car, she collapses. Her parents notice she has an urticarial rash and retrieve her adrenaline injector from the car. However, they discover their 150µg adrenaline autoinjector has expired and decide against using it.