Hereditary angioedema (HAE) is a rare genetic disorder causing a deficiency in C1 esterase inhibitor (C1-INH) that is manifested through unpredictable oedema. We describe a case of a patient with HAE who had previously been refused surgery for tonsillitis due to the potential for oedema, in whom regular monitoring of C1-INH levels combined with intensified therapy with danazol, tranexamic acid and C1-INH concentrate enabled an uncomplicated procedure with no oedema crisis. However, clinicians should be alerted that higher overall dosages of C1-INH concentrate for perioperative prophylaxis may be required than those typically used to treat acute HAE attacks.