There are 4 allergens found in oranges.
Cit s 1 is a germin like protein (GLP). These proteins have a role in guarding against stress and pathogens in the plant.
Cit s 2 is a profilin protein. Allergenic profilins are found exclusively in flowering plants and are minor pollen allergens.
Cit s 3 is a lipid transfer protein (LTP). These proteins are resistant to heat and are found in many types of plants. Patients suffering from a more severe allergy to cooked fruit may be sensitised to this group of proteins
Cit s 7 is a gibberellin regulated protein. Gibberellins are plant hormones associated with growth and development.
You may be suffering from LTP Syndrome if you have reactions to various fruits, vegetables and nuts and your reactions continue to be severe after you have discarded the peel and have cooked the food.
Common foods involved in LTP allergy include kiwi, strawberries, sunflower seeds, walnut, apple, mulberry, banana, pea, apricot, cherry, plum, almond, peach pomegranate, raspberry, tomato, grape, celery, peanut, asparagus, cabbage, broccoli, chestnut, lemon, tangerine, orange, hazelnut, lettuce, lentils, lupin, green bean, pear, mustard, wheat and maize.
Orange allergy is broadly linked to other fruit profilin allergies. Allergy to melon, watermelon, tomato, banana, pineapple and lychee may be considered as a marker of profilin hypersensitivity.