https://www.nps.org.au/australian-prescriber/articles/antihistamines-and-allergy

Clinical featuresAny acute onset of hypotension or bronchospasm or upper airway obstruction where anaphylaxis is considered possible, even if typical skin features are not present OR Any acute onset illness with typical skin features (urticarial rash or erythema/flushing, and/or angioedema) PLUSInvolvement of respiratory, cardiovascular, or persistent severe gastrointestinal symptoms 1 Immediate action • Call for assistance.• Lay the patient flat -do not allow them to stand or walk.If unconscious place in recovery position and maintain airway.If breathing is difficult allow the patient to sit (as illustrated).2 Give INTRAMUSCULAR ADRENALINE (EPINEPHRINE) into mid-lateral thigh without delay Adrenaline dose chart (1:1000 ampoules containing 1 mg adrenaline per 1 mL) Age (years) Weight (kg) Adrenaline volume 1:1000 Autoinjector An adrenaline autoinjector, e.g.EpiPen, may be used instead of an adrenaline ampoule and syringe.