Apple is a food which may result in allergy symptoms in sensitised individuals

Apple Allergy Test: Allergen Exposure

Apples are one of the most widely cultivated and consumed foods in the Western hemisphere, and are grown to be eaten fresh, as cooking ingredients and for the production of apple juice or cider. There are a wide variety of cultivars with a range of textures and colours.

Varieties of apple can be divided into “summer” and “late autumn” groups, according to the time of year at which the fruit matures and is harvested. They grow in temperate climates, and ripen as soon as the fruit is removed from the tree. Apples can be stored for up to several months with the use of controlled atmosphere chambers which delay the onset of ripening.

The apple is also a source of pectin, which is used as a gelling agent in jams and preserves, as well as in laboratory cultures. Dried apple may be treated with sulphites or sulphur dioxie to inhibit browning.

Apple contains over 266 volatile components that include alcohol, esters, aldehydes, ketones, ethers, acids, bases, acetals, and hydrocarbons.

Apple Allergy Test: Allergen Description

Apple contains a number of recognised allergens, contained in the pulp and peel, as well as the seeds, although these are rarely consumed. Apple peel has been reported to have a higher allergenicity than apple pulp.

Different apple cultivars have markedly different amounts of major allergens. Strains such as Granny Smith or Golden Delicious are anecdotally reported to be highly allergenic, whereas strains such as Jamba, Gloster or Boskop display mild to no allergenic effects.

The level of allergenic protein in apples has been shown to vary according to the ripeness of the individual fruit, as well as with the variety, with a higher allergen content displayed in apples which have matured or been stored for longer periods of time.

Apple Allergy Test: Potential Cross-Reactivity

Cross-reactivity among the different strains of apple has been frequently observed. In addition studies have reported cross-reactivity between birch pollen and a number of foods, including apple, pear, celery, carrot and potato.

Apple Allergy Test: Clinical Experience

Allergy to apple has been documented for over 30 years, and frequently induces symptoms of food allergy, most commonly oral allergy syndrome, in sensitised individuals.

Itching, tingling and other mild reactions on the oropharyngeal mucosa are the most common complaints from eating the raw fruit. Angioedema, urticaria and shock are less common. Other symptoms may include rhinoconjunctivitis, asthma, laryngeal oedema, abdominal effects, pruritis and hand dermatitis.

Where individuals are highly sensitised to allergens present in apples, symptoms may result even from kissing. This may result in in local or regional, mild, moderate or severe symptoms, including angioedema, bronchospasm, acute respiratory distress and anaphylaxis.

An increase in clinical reactivity to apples has been observed in birch pollen-allergic individuals during the birch-pollen season.

Other reactions

All members of this genus contain the toxin hydrogen cyanide in their seeds. Apple seeds do not normally contain very high quantities of hydrogen cyanide, but even so they should not be consumed in large quantities.

An anaphylactic reaction has been recorded to apple juice containing acerola, the allergy reaction being to the acerola.