Sir,

We read with interest the case report by Varma et al1 regarding a case of presumed orbital cellulitis after peribulbar anaesthesia for cataract surgery. The patient presented 2 days postoperatively with periorbital oedema, redness, proptosis, conjunctival chemosis, and restriction of ocular movements on the operated eye, and improved following treatment with intravenous antibiotics.

We would like to report three cases, which presented 1–2 days postoperatively with the same apparent clinical appearance and outcome, but which we believe to represent a different diagnosis. All three cases presented with periorbital swelling within 48 h of surgery after uncomplicated peribulbar anaesthesia. Patients had mild (one or two lines) reduction of Snellen's visual acuity and no RAPD. There was no purulent discharge from the eye. All patients were apyrexial. Antibiotic treatment was not administered as the signs were attributed to an allergic reaction to hyaluronidase rather than infection, but the patients were closely observed.

As in Varma's case, each had a peribulbar anaesthesia, which included hyaluronidase. In all our cases, there had been previous exposure to hyaluronidase in the same or fellow eye, implying that sensitisation had taken place. Varma et al do not comment on whether their patient had had previous exposure to hyaluronidase, but she did have previous cataract surgery to the fellow eye, and may therefore have been sensitised.

The rapid onset of signs in the absence of pyrexia and with negative blood and tissue cultures in the case noted by Varma et al, lend support to the possibility that this case may also have been allergic rather than infection. Allergy to hyaluronidase is a recognised complication. In cases noted by Kirby et al,2 Minning3 and Taylor et al,4 a type I allergic reaction to hyaluronidase during surgery was confirmed later with skin-patch testing. A feature of these reactions was marked periorbital oedema.

The possiblity of allergic reaction to hyaluronidase should be considered when a patient presents with a rapid onset of signs, especially if the patient has had previous exposure to hyaluronidase.