Allergic reactions during anaesthesia

The incidence of life-threatening hypersensitivity reactions occurring during anaesthesia is around one in 10,000 procedures. Muscle relaxants are involved in over two thirds of the cases. Antibiotic administration is a frequent cause.

The mortality rate from these reactions is about 3-6%.

Successful immediate treatment requires prompt recognition by the attending anaesthetist. Adrenaline (epinephrine) remains the mainstay of treatment, with corticosteroids and antihistamines providing limited benefit in the acute situation.

Subsequent investigation aims to determine the responsible agent to allow its future avoidance. Skin testing is often useful to identify potentially cross-reactive compounds and appropriate therapeutic alternatives. This is done weeks after the initial reaction to allow the immune system to reset itself. However, skin testing can be misleading in giving false positive and false negative results.