Summary

The olive tree is native to the Mediterranean and has been cultivated and utilized by humans for more than 5,000 years. The olive fruit is a global agricultural and dietary resource, particularly in Mediterranean countries. Despite common allergy to its tree pollen and widespread consumption, food allergy to olive fruit is rarely observed. One olive fruit allergen has been described, Ole e 13, a thaumatin-like protein

Epidemiology

Worldwide distribution

Despite common allergy to its tree pollen and widespread consumption, food allergy to olive fruit is rarely observed, with reports being limited to individual cases.

Route Of Exposure

Main

Ingestion.

Secondary

Contact.

Clinical Relevance

Allergic reactions due to ingestion of olive fruit or oil are rare. One 19-year-old female patient experienced episodic angioedema of the face, neck, hands and tongue 15–30 minutes after olive ingestion. The symptoms abated after 24 hours. No reaction was seen after olive oil ingestion and rhinitis/asthma was not experienced during the pollen season. Skin prick testing (SPT) with three different olive brands gave a positive result (9.7 mm), where 5 controls subjects showed a negative skin test. IgE antibody testing was also positive.

Another case study of a 28-year-old man with a 3-year history of persistent rhinitis and seasonal exacerbation reported palatal itching after ingestion and generalized urticaria consistently following olive fruit consumption. These symptoms subsided spontaneously within a few hours. SPT was positive to olive-fruit extract, fresh green and black olives, and olive pollen. Specific IgE was also positive for olive fruit and olive pollen.

A further case study of a 21-year-old woman with a history of house dust mite allergic rhinitis and asthma reported three episodes of oropharynx and palms itching, cough and dyspnea a few minutes after eating a snack with onion, gherkin, red pepper and olive. These symptoms subsided with beta-2-agonists and antihistamines after a few hours. SPT were positive to olive fruit (raw material), olive oil and mites, and were negative to pollens (including olive pollen). Five control subjects showed a negative test with olive fruit. Total IgE was positive for mites and negative to pollens and foods.

Atopic Dermatitis

Olive, olive oil and olive wood have also been implicated in allergic contact urticaria and dermatitis, in these cases, patients appear to be sensitized by topical treatments. Reports of occupational allergic contact dermatitis have been described in pedicurist, masseur, pizza maker and beautician.

Cross-Reactivity

There have been reports of olive fruit allergy after pollen immunotherapy, suggesting the presence of a common allergen structure both in olive pollen and in olive fruit.