[Two patients with chlorhexidine allergy--anaphylactic reactions and eczema]

A 14 year-old girl experienced a combined delayed and immediate type of allergy to chlorhexidine. She first developed an eczematous reaction in the face following the long-term application of an antiacne preparation. Use test (repeated Open Application Test, ROAT) on the forearm was positive. Epicutaneous tests with 1% chlorhexidine gluconate and acetate were both positive. About six months later she developed an urticarial rash and syncope after cleansing the skin with chlorhexidine gluconate. Prick tests were positive to 0.05% chlorhexidine gluconate and to 0.01% of the acetate solution. A 30 year-old man developed anaphylactic symptoms following treatment with an antiseptic dental gel containing 1% chlorhexidine gluconate. Prick test was positive to the gel and to chlorhexidine gluconate 0.5%.