Positive intradermal tests to D-tubocurarine in patients with cholinergic urticaria

Patients with cholinergic urticaria exhibit increased hypersensitivity to cholinergic drugs. In the present study, an attempt was made to determine whether these patients would also cross-react to various neuromuscular blocking agents having structures analogous with acetylcholine. The four patients tested showed positive skin tests for D-tubocurarine at concentrations of 1/10,000. None of the 10 subjects in the control group and none of the patients with urticaria had positive responses, not even to a 10-fold higher concentration of D-tubocurarine. These findings suggest that caution should be exercised in the use of neuromuscular blocking agents in patients with cholinergic urticaria.