Spice allergy: results of skin prick tests and RAST with spice extracts

Skin prick tests (SPT) with freeze-dried spices and 5% (w/v) spice extracts were performed on 50 patients with 2+ or stronger SPT reactions to spices per se, and RAST were performed on 10 of them. Freeze-dried extracts produced mostly equal or stronger SPT reactions than corresponding whole spices, but 5% (w/v) extracts produced weaker reactions and also remained totally negative in some patients. Positive RAST results were seen in all 10 patients tested. The correlation between the RAST and SPT results was good for mustard and paprika, but poor for cayenne, coriander, caraway and white pepper. Five patients with positive SPT and RAST for spices contracted rhinitis from powdered spices in their working environments, and one patient suffered from gastrointestinal pains caused by spiced food. The others had noticed no clinical symptoms caused by spices. The present results thus indicate that both SPT and RAST should include purified spice extracts.