IgE-mediated reactions
Sensitisation to Liliaceae has also been observed. Garlic, Onion or chive sensitivity was observed in 4.6% of skin prick tests in children, and in 7.7% in adults. No positive skin-specific IgE test occurred for Nutmeg, Ginger and Clove (1).
Skin-specific IgE tests with powdered commercial spices performed in 70 patients with positive skin-specific IgE test for Birch and/or Mugwort pollens and Celery yielded a report of positive tests in more than 24 patients for Anise, Fennel, Coriander or cumin—all from the same botanical family (Apiaceae) as Celery. Spices from unrelated families (Red Pepper, White Pepper, Ginger, Nutmeg, Cinnamon) elicited positive immediate skin test reactions in only 3 of 11 patients(2).
Allergic reactions have been reported to inhalation of Ginger dust (3).
Although tests for Ginger allergy have predominantly been for immediate hypersensitivity reactions, a greater prevalence of Ginger allergy is recorded using tests for delayed allergy reactions. Of 55 patients with suspected contact dermatitis, patch test results (positive at concentrations of 10% and 25%) were most common with Ginger(3) , Nutmeg (1), and Oregano (4); the remaining spices produced 0 or 1 positive responses (5).
Of about 1,000 patients investigated for occupational skin disease, 5 had occupational allergic contact dermatitis from spices. All patients had hand (or finger) dermatitis. The causative spices were Garlic, Cinnamon, Ginger, Allspice and Clove (6).
Other reactions
Anecdotally, excess Ginger ingestion has been said to cause irritation of the urethra.
As with a number of other common herbal remedies, such as Feverfew, Garlic, Ginkgo, and Asian ginseng, Ginger may increase the risk of bleeding during surgical procedures or potentiate the effects of warfarin therapy (7-9).
However, a study concluded that the effect of Ginger on thromboxane synthetase activity is dose-dependent, or only occurs with fresh Ginger, and that up to 2 g of dried Ginger is unlikely to cause platelet dysfunction when used therapeutically (10)
