Pretreatment with systemic corticosteroid can mask early symptoms of hypersensitivity reaction to hyaluronidase following peribulbar block.

Hyaluronidase is a hydrolytic enzyme that helps in breaking down hyaluronic acid, a component of the extracellular tissue matrix, thereby facilitating the dispersion of local anaesthetic drugs through tissue planes. It is a key component in peribulbar anaesthesia for ocular surgeries. Allergic response to hyaluronidase is relatively rare but a potentially vision-threatening complication. A preoperative intradermal hypersensitivity test is useful to detect such cases and avoid potential complications. Here we report a case of hypersensitivity reaction to hyaluronidase after peribulbar anaesthesia for cataract surgery where an intradermal hypersensitivity test was falsely negative, and presentation was delayed due to the use of preoperative systemic corticosteroids. However, correct, and timely diagnosis and treatment saved the eye from permanent vision loss.