Anaphylaxis is a life-threatening allergic reaction requiring immediate intervention. Supportive management includes removing triggers, administering oxygen, establishing large-bore IV access, fluid resuscitation, antihistamines, bronchodilators, and promethazine. The first-line definitive treatment is IM adrenaline 0.5mg, repeated if needed, followed by infusion for refractory cases. Steroids (hydrocortisone) and H1/H2 blockers (e.g., diphenhydramine) are adjuncts. Close monitoring for 1–24 hours is crucial due to the risk of biphasic reactions, with an average observation time of 8 hours. Hospital admission is warranted for severe cases, need for repeat adrenaline, fluid boluses, or comorbidities like uncontrolled asthma.