D2.282 - IgE-mediated anaphylaxis to quinine confirmed with a basophil activation test
Case report
Introduction
There are several published cases of fixed drug eruptions associated with tonic water. However, IgE-mediated hypersensitivity reactions to tonic water are extremely rare. We present the first case in which an IgE-mediated reaction to tonic water was confirmed with a basophil activation test (BAT).
History
A 39-year-old woman with allergic rhinitis to grass and cat developed pruritus of the palms, flushing, lower abdominal pain, and a sensation of collapse 30 minutes after eating for cashews as well as 125 ml of Schweppes tonic water. She was transported to the emergency room (ER). Her vital signs were normal and a generalized urticaria was documented. Intramuscular adrenaline, clemastine and methylprednisolone were administered, and she was discharged the next day. The serum tryptase was 14,9 ng/ml (< 11,4 ng/ml). 9 months prior to this episode she had consumed a gin and tonic without issues.
Three months after the index reaction she experienced similar symptoms after two sips of gin and tonic (Fever Tree), after which she took levocetirizine 10 mg and prednisone 100 mg. Due to worsening symptoms (protracted vomiting and lower abdominal pain), she went to the ER, where i.m. adrenaline was administered twice, as well as methylprednisolone and clemastine. The serum tryptase was 9.9 ng/ml (basal tryptase 5,9 ng/ml).
Allergy evaluation
Skin prick testing (SPT) to a panel of aeroallergens was positive for grass pollen and cat. SPT was negative for Schweppes tonic water. The BAT revealed a type I sensitization to quinine. The patient declined a challenge with tonic water.
Conclusion
IgE-mediated hypersensitivity reactions to tonic water appear to be extremely rare, with only three previous case reports. To our knowledge, our patient is the first in which an IgE-mediated hypersensitivity reaction to quinine was confirmed with a BAT. This test can be a useful diagnostic tool, especially in patients in which the SPT is negative and the measurement of quinine specific IgE is not commercially available.
