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

Olive Allergy Test: Allergen Exposure

Olive is the small, pitted fruit (a drupe) of the olive tree which may be the first tree to have been cultivated by humans. Olive oil production is recorded as early as 3000 BC. The olive tree is found in the Mediterranean Basin from Portugal to the Levant, the Arabian Peninsula, and southern Asia as far east as China, as well as the Canary Islands and Réunion.

The olive fruit is of great agricultural importance, principally as the source of olive oil which is a core ingredient in Mediterranean cuisine and a globally prized commodity. Olives are one of the most extensively cultivated fruit crops in the world. Olive oil is used both as a cooking oil and as a flavourant.

About 90% of all harvested olives are turned into oil, while about 10% are used in their unpressed state. Olives themselves are a versatile ingredient. They are eaten as snacks and in dishes, baked in bread, used in salads and on pizza.

Olive Allergy Test: Allergen Description

Although 9 allergens have been characterised in olive tree pollen, only one allergen from the fruit of this plant has yet been characterised, a thaumatin-like protein.

Olive Allergy Test: Potential Cross-Reactivity

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

Olive Allergy Test: Clinical Experience

Although olive pollen may commonly induce symptoms of allergy (hayfever and asthma) in sensitised individuals, the olive fruit only uncommonly induces symptoms of food allergy in sensitised individuals.

Contact urticaria to olive was described in a 22-year-old woman who presented with a 2.5-year history of hand dermatitis, which had started while she was working as a pizza chef. She gave a further history of perioral itching and lip swelling after consuming olive, with the severity dependent on the type of olive.

Olive oil, produced from olive fruit, has been more frequently reported to result in adverse effects in sensitised individuals than has olive fruit.

An early study reported that 13 cases of contact allergy to olive oil were documented, but that known components of olive oil could not be proven to be the cause of the allergy.

Airway disease has been described in an olive oil mill worker. A 41-year-old Spanish man working in an olive oil mill reported a 2-year history of episodic rhinitis, shortness of breath, chest tightness, and wheezing. Symptoms occurred within 30 minutes after he arrived at the workplace, and partially improved immediately after he left it.

Twenty cases of contact allergy to Olive oil were described, and 3 of these involved occupational hand eczema as a result of exposure to olive oil. Researchers describe a masseur who was allergic to olive oil, resulting in occupational hand eczema.

Other compounds present or forming in olive oil may be responsible for the allergy-like reactions reported. Olive oil may contain lipid peroxidases, which can be inducers of irritant skin reactions. This is because unsaturated lipids in olive oil are susceptible to oxidation by oxygen in the air.

Furthermore, olive oil may be contaminated with benzene or benzene derivatives such as toluene and C2 benzenes.