{'fraction_non_alphanumeric': 0.02613240418118467, 'fraction_numerical': 0.018728222996515678, 'mean_word_length': 4.7425, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Angioedema during dental treatment

The patient (female) first noticed tightness in her throat about 30 min after a black rubber dental dam (Ash, Amalgamated Dental Trade Distribution Ltd.) had been positioned over her lower lip for some preliminary dental work. Within minutes of being injected with mepivacaine, her lower lip, mouth and then face swelled extensively. She had never experienced a similar reaction in the past, although skin contact with certain rubbers had produced itchy local swelling, usually progressing to an eczematous reaction. Prick tests to I % lignocaine, 3% mepivacaine and normal saline produced weals measuring less than 8 mm in diameter. Intradermal injection of 0.1 ml aliquots gave an exaggerated response to mepivacaine and saline, both attaining a maximum diameter of 18 mm at 30 min, in contrast to lignocaine which produced a weal measuring 8 mm. When the saline skin test was repeated 4 months later, there was an identical response. Sterile water also produced a weal with a maximum diameter of 14 mm. Patch tests to lignocaine (5% ointment, 1 and 2% aqueous) and caine-mix were negative. Open and closed patches to 0.5% PPD, 0.1 % IPPD and 0.6% PPD-mix were also negative at 30 min, 48 and 96 h. Scratch tests with the rubber chemicals gave an exaggerated linear weal along the scratch line below the PPD patch only. There was no immediate reaction to the black rubber dam, applied as an open patch for 10 min, but a marked oedematous response was seen with closed patch tests at 48 and 96 h. Her serum IgE was greater than 1000 units (normal range < 81). Dermographism could not be elicited at less than 15 units on the standard dermographometer scale. It is uncertain whether the observed wealing reaction to mepivacaine injection was relevant because of the similar and unexpected response to saline. However, the patch tests suggest that a reaction to the dental dam may well have been responsible for her episode of angioedema. Our patient appears to have an unusual non-specific hyperactivity to skin trauma even though tests for dermographism were negative. Her case illustrates the difficulty in defining local anaesthetic 'allergy' and suggests that the development of angioedema during dental treatment may, in some instances, be multifactorial.