Watermelon Allergy Test
Latin name: Citrullus vulgaris/Citrullus lanatus
Source material: Fresh fruit
Common names: Watermelon
Watermelon is a food which may result in allergy symptoms in sensitised individuals.
Watermelon Allergy Test: Allergen Exposure
Watermelon is cultivated widely in tropical and sub-tropical climates, and is an especially popular seasonal fruit in the southern United States. The plant has trailing vines and very large fruit with smooth, thick, green skin, and sometimes darker green stripes.
The flesh is sweet, and pink, red or yellow in colour with embedded brown or black seeds, although seedless varieties have been developed through selective cultivation.
The fruit is commonly eaten in large slices, with the rind serving as a base, or in balls or cubes in fruit salads. The high water content makes the flesh impractical for cooking or preserving, but the rind is sometimes pickled.
Watermelon Allergy Test: Allergen Description
Several allergens present in watermelon have been characterised, these include a profilin, a malate dehydrogenase and a triosephosphate isomerase.
Watermelon Allergy Test: Potential Cross-Reactivity
Extensive cross-reactivity betwen the different individual species of the genus could be expected and has been reported.
Cross-reactivity has been demonstrated between pumpkin, pumpkin seed, musk melon, watermelon, cucumber and zucchini.
The melon profilin showed substantial cross-reactivity with profilin from tomato, peach, grape and Bermuda grass pollen. However, cantaloupe, watermelon, banana and Kentucky blue grass displayed no notable cross-inhibition.
Hypersensitivity to Bet v 2, a profilin, has been reported to be strongly associated with clinical allergy to citrus fruits, melon or watermelon, banana and tomato.
ELISA inhibition assays demonstrated allergenic similarity among celery, cucumber, carrot, and watermelon.
Allergy to watermelon has been associated with other allergies, e.g. to melon and latex.
In a study, the most common foods found to be associated with melon allergy were avocado, banana , kiwi, watermelon, and peach.
An association between grass pollinosis and sensitisation to tomato, potato, green pea, peanut, watermelon, melon, apple, orange and kiwi has been reported.
Watermelon and ragweed have been proposed as having similar allergens.
Watermelon Allergy Test: Clinical Experience
Watermelon may uncommonly induce symptoms of food allergy in sensitised individuals. Allergic reactions include oral allergy syndrome or oropharyngeal symptoms (itching and/or swelling of the lips, tongue, or throat), urticaria, dermatitis, angioedema, and dyspnoea.
In a study of 29 watermelon-sensitive patients, 6 were symptomatic. Only about 25% of patients with specific IgE to watermelon develop oropharyngeal symptoms. Symptoms include itching and/or swelling of the lips, tongue, or throat.
In an Indian study of 24 children aged 3 to 15 years with documented deterioration in control of their perennial asthma during the months of August and September, it was reported that 19 (79%) were sensitised to watermelon.
Contact urticaria from watermelon in a 45-year-old woman with pollen allergy has been reported. She developed urticaria and swelling of her lips on eating watermelon. Symptoms worsened every season and finally resulted in hospital admission following the onset of generalised urticaria, swelling of the lips and tongue, breathing difficulty, and hypotension.
Intestinal obstruction and rectal bezoar by watermelon seed has been reported.
Watermelon seeds, found in children who had aspirated foreign bodies, were the most common foreign bodies aspirated.