Bay leaf is a food which may result in allergy symptoms in sensitised individuals.

Bay Leaf Allergy Test: Allergen Exposure

The bay tree originated in Asia, and then spread to the Mediterranean and regions with similar climates. The bay leaf has long been used by humans for flavouring, particularly in Mediterranean cuisine where it is a common ingredient in soups, stews, meats, fish, stuffings and pâtés.

The most common method of use is to submerge one or more leaves, either whole or partly broken to release the oils, in a sauce as it cooks, and then to remove before serving. Crushed leaves are sometimes used to increase the amount of flavour imparted, in which case they are usually enclosed in a muslin bag to facilitate removal.

Bay leaf is also used in pickling and marinating, as well as to flavour the aromatic alcoholic drink vermouth (bay leaf oil).

In Indian and Pakistani cuisine it is often used in rice based dishes, including biryani, and also as a constituent ingredient in garam masala. In the Philippines, the dried leaves are used in several local recipes, including menudo, beef pares, and adobo. Bay leaves are also used in the making of jerk chicken in Caribbean countries.

Bay oil has been rubbed on rheumatic joints for pain relief. It may be used in aromatherapy. In ancient times, the leaves were chewed for their purportedly hallucinogenic properties.

Bay Leaf Allergy Test: Allergen Description

No allergens present in bay leaf have yet been characterised.

Bay Leaf Allergy Test: Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, but in fact does not occur frequently.

Cross-sensitisation has been demonstrated between 2 allergenic plants, Frullania (a liverwort) and Laurus nobilis (bay leaf).

Bay Leaf Allergy Test: Clinical Experience

Anecdotal evidence suggests that bay leaf may cause symptoms of food allergy in sensitised individuals; however, no studies have been reported to date.

A number of reports have described allergic dermatitis resulting from contact with bay leaf. Occupational asthma from inhalation of bay leaf allergen may also occur. The prevalence of allergy to bay leaf could be expected to be higher in occupational settings, in particular in the food industry.

Perioral dermatitis and perioral contact eczema with eczematous stomatitis as a result of hypersensitivity to bay leaf have been reported.

An individual with occupational asthma caused by several aromatic herbs –thyme, rosemary, bay leaf, and garlic – has been described. The diagnosis was confirmed by several inhalation challenges.

Allergic contact dermatitis from the leaf and the oil has been described. A 55-year-old woman presented with erythema and oedema over her knees, 3 days after the application of laurel oil to relieve joint pain. A patch test to the oil was positive.

Other reactions

A number of studies have indicated that bay leaf may result in physical obstruction, including duodenal obstruction secondary to bay leaf impaction.