f268 Clove

IgE-mediated reactions

Anecdotal evidence suggests that clove may induce symptoms of food allergy in sensitized individuals; however, few studies have been reported to date. It is possible that the allergy occurs more frequently than has been reported. Tests for specific IgE assess immediate hypersensitivity reactions, and clove allergy has been infrequently reported.

According to the CICBAA data bank in France, in skin-specific IgE tests conducted for spice carried out in 589 patients with food allergy and suspected food allergy to spices, frequent sensitisation to Apiaceae was observed, in coriander, caraway, fennel and celery. No patients were found to be allergic to clove. (1)

However, in a study of Type VI delayed-hypersensitivity reactions to spice, clove caused the most reactions. Nine common spices were tested epicutaneously in 338 dermatological patients, 118 of whom were allergic to balsam of Peru; positive reactions to 1 or more spices were seen in 50 patients. The spices giving positive reactions most often were clove, Jamaica pepper and cinnamon (cassia). (2) Similarly, patch tests with a number of spices on 29 patients yielded the report that positive reactions to balsam of Peru were seen in 17 patients, and to clove, Jamaica pepper or cinnamon in 5. (3)

Of 1 000 patients investigated for occupational skin disease, 5 had hand (or finger) occupational allergic contact dermatitis from spices. The causative spices were garlic, cinnamon, ginger, allspice and clove. (6)

Clove and clove oil contain eugenol. An early survey indicated that, at the concentrations present in consumer products, eugenol alone or as part of clove leaf oil has a very low potential to elicit pre-existing sensitisation (‘elicited’ reactions) or to induce hypersensitivity (‘induced’ reactions). (4)

Occupational allergic contact dermatitis from eugenol, oil of cinnamon and oil of cloves was described in a physiotherapist. (5) The frequency of responses to selected fragrance materials in 218 fragrance-sensitive subjects was evaluated in 8 centres worldwide, using a fragrance mixture and 17 less well-studied fragrance materials. Reaction to the fragrance mixture occurred in 76% of the subjects, and 93% of the reactions were to clove bud oil. (6)

Other reactions

The results of a study done on rats suggest that eugenol has anti-anaphylactic properties in preventing mast cell degranulation. (7)

Clove, present in an herbal product, was said to potentially increase the risk of bleeding or potentiate the effects of warfarin therapy. (8) Two antiplatelet components have been isolated and identified: eugenol and acetyl eugenol. They inhibited arachidonate-, adrenaline- and collagen-induced platelet aggregation. (9) Acetyl eugenol, a component of oil of cloves, was reported to inhibit aggregation of platelets and to alter arachidonic acid metabolism in human blood platelets. (9)

Health effects, including severe pulmonary toxicity, are suspected to be associated with clove cigarette (kretek) use among adolescents and young adults. The most likely candidate for a specific toxic effect, of the chemical constituents of kreteks, is eugenol. (10) Inhaling clove cigarette smoke has been associated with severe lung injury in a few susceptible individuals with prodromal respiratory infection.

No allergens from this plant have yet been characterized.

Cross-reactivity

Cross-reactivity can be expected among the different species of the genus. (11)

Clove and allspice have often been reported to provoke allergic patch-test reactions in patients allergic to balsam of Peru, a phenomenon thought to be a result of these spices containing several of the same or related substances, e.g. cinnamic aldehyde, eugenol and vanillin. (2)

Last reviewed: April 2022