Cross reactivity

Individuals who react to specific food allergens, inhalants or substances can develop an allergy to others. Such reactions may be to different foods containing the same allergen, or to an allergen with a very similar protein structure. Reactions can be either light or heavy and are known as allergic cross-reactivity.

This means that someone may suffer an allergic reaction even when avoiding the foods they know they are allergic to. If someone is allergic to peanuts, for example, they might react to soya, peas, lentils or beans – food items in the same biological family (legume).

Allergic cross-reactions can also happen between certain fruit or vegetables and latex (known as latex-food syndrome), or the pollens that cause hay fever.

If a person has a measurable reaction to a certain food with clinical diagnosis, avoiding similar foods that could trigger this reaction may be helpful.

The most well-documented cross-reactivity occurs between apple and birch pollen; however, individuals who are allergic to apple are not necessarily allergic to birch pollen. Cross-reactivity should not be assumed, and important foods should not be eliminated from the diet without appropriate testing and clinical diagnosis.

Aniseed

Clinical relevance

Light

Frequent occurrence

Mugwort

Possible occurence

Birch, weeping

Apple

Clinical relevance

Medium

Frequent occurrence

Birch, weeping

Possible occurence

Celery; Cherry; Cocksfoot; Mugwort; Peach; Pear; Potato; Ragweed, common; Rye-grass; Tomato

Alder pollen

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Almond; Apple; Celery; Cherry; Hazelnut; Parsley; Peach; Pear

Ash, common

Clinical relevance

Light

Frequent occurrence

Birch, weeping; Lilac, common; Olive

Possible occurence

Privet, common; Ragweed, common; Timothy

Avocado

Clinical relevance

Medium

Frequent occurrence

Latex

Possible occurence

Banana; Kiwi

Banana

Clinical relevance

Heavy

Frequent occurrence

Latex

Possible occurence

Avocado; Birch, weeping; Goose-foot Kiwi; Melon

Bermuda grass

Clinical relevance

Light

Frequent occurrence

Blue grass, (Kentucky); Cocksfoot; Reed, common; Ryegrass, perennial; Timothy

Possible occurence

Celery; Olive; Rape, oilseed; Rye-grass; Sunflower, common

Birch pollen

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Almond; Apple; Apricot; Buckwheat; Carrot; Celery; Cherry; Coriander; Fennel; Hazel nut; Honey; Kiwi; Nectarine; Parsley; Parsnip; Pear; Peach; Peanut; Pepper; Plum; Potato; Prune; Spinach; Walnut; Wheat

Birch, weeping

Clinical relevance

Heavy

Frequent occurrence

Apple; Ash, common; Beech, common; Carrot; Celery; Chestnut, sweet; Cob, hazel; Curry; Hornbeam, common; Kiwi; Oak, English; Pear; Tomato

Possible occurence

Aniseed; Banana; Elm, Scottish; Caraway seed; Chamomile, German; Cherry; Coriander; Fennel seed; Hazelnut; Latex; Lychee; Mango; Mugwort; Olive; Orange; Paprika, condiment; Parsley; Peach; Pepper; Potato; Rape, oilseed; Rye-grass; Soy beanTimothy

Carrots

Clinical relevance

Heavy

Frequent occurrence

Birch, weeping; Celery; Mugwort

Possible occurence

Cucumber; Head Lettuce; Mango; Melon

Cherry

Clinical relevance

Light

Frequent occurrence

Possible occurence

Birch, weeping; Apple; Peach

Chicken egg

Clinical relevance

Heavy

Frequent occurrence

Canary (serinus canarius); Chicken; Duck, domestic; Goose, domestic; Hen, domestic; Parrot, African gray (psittacus erithacus); Parakeet (nmphicus hollandicus) feathers; Parakeet (Melopsittacus undulatus); Pigeon

Possible occurence

Cocksfoot grasses

Clinical relevance

Heavy

Frequent occurrence

Bermuda grass; Blue grass, (Kentucky); Melon; Oat flour; Rye flour; Ryegrass, perennial; Timothy; Vernal grass, scented

Possible occurence

Apple; Meadow, fescue; Oats, common; Reed, common; Rye-grass

Cod fish

Clinical relevance

Light

Frequent occurrence

Possible occurence

Carp; Eel; Herring; Mackerel; Plaice; Salmon; Sole; Tuna fish

Corn

Clinical relevance

Light

Frequent occurrence

Possible occurence

Barley; Blue grass, (Kentucky); Millet; Oats, common; Soy bean; Ryegrass, perennial; Rice; Wheat, common

Crab

Clinical relevance

Light

Frequent occurrence

Possible occurence

Oyster; Shrimp; Squid

Cucumber

Clinical relevance

Light

Frequent occurrence

Celery

Possible occurence

Carrot; Melon

Curry mixed spices

Clinical relevance

Medium

Frequent occurrence

Birch, weeping; Celery; Mugwort

Possible occurence

Edible chestnut

Clinical relevance

Medium

Frequent occurrence

Latex

Possible occurence

Fennel seed

Clinical relevance

Light

Frequent occurrence

Possible occurence

Birch, weeping; Celery Mugwort

Grape

Clinical relevance

Light

Frequent occurrence

Possible occurence

Peach

Grass pollen

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Melon; Orange; Swiss chard; Tomato; Watermelon; Wheat

Hazlenut

Clinical relevance

Heavy

Frequent occurrence

Cob, hazel

Possible occurence

Birch, weeping; Kiwi; Mugwort; Peach; Poppy seed; Rue flour; Sesame

Kiwi fruit

Clinical relevance

Medium

Frequent occurrence

Birch, weeping; Latex; Timothy

Possible occurence

Avocado; Banana; Hazelnut; Mugwort; Poppy Seed; Rye flour; Ryegrass, perennial; Sesame

Latex rubber

Clinical relevance

Heavy

Frequent occurrence

Avocado; Banana; Edible Chestnut; Ficus benjamini (Tropic laurel, Weeping fig); Kiwi; Mango; Melon; Papaya; Tomato

Possible occurence

Apple; Birch, weeping; Buckwheat; Carrot; Celery; Dill; Fig; Mugwort; Orange; Oregano; Passion fruit; Peach; Peanut; Pear; Pineapple; Potato; Ragweed, common; Rye-grass; Sage; Soy bean; Strawberry; Timothy; Walnut

Lentil

Clinical relevance

Light

Frequent occurrence

Possible occurence

Pea; Walnut

Lychee

Clinical relevance

Light

Frequent occurrence

Possible occurence

Birch, weeping

Melon

Clinical relevance

Medium

Frequent occurrence

Celery; Cocksfoot; Latex; Ragweed, common

Possible occurence

Banana; Carrot; Cucumber; Goose-foot; Plantain, English; Zucchini

Mugwort pollen

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Carrot; Celery; Coriander; Fennel; Melon; Parsley; Pepper; Spices; Sunflower; Watermelon

Onion

Clinical relevance

Light

Frequent occurrence

Possible occurence

Asparagus; Garlic; Timothy

Orange

Clinical relevance

Heavy

Frequent occurrence

Possible occurence

Birch, weeping

Papaya

Clinical relevance

Light

Frequent occurrence

Latex

Possible occurence

Paprika condiment

Clinical relevance

Light

Frequent occurrence

Possible occurence

Birch, weeping; Celery; Mugwort

Pea

Clinical relevance

Light

Frequent occurrence

Possible occurence

Lentil; Mugwort; Peanut

Peanut

Clinical relevance

Heavy

Frequent occurrence

Tomato

Possible occurence

Latex; Lentil; Mugwort; Parietaria; Pea; Peach; Soy bean

Pear

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Apple; Birch, weeping; Mugwort; Peach

Pepper

Clinical relevance

Light

Frequent occurrence

Possible occurence

Celery; Birch, weeping; Mugwort

Pineapple

Clinical relevance

Light

Frequent occurrence

Possible occurence

Latex; Rye-grass

Poppy seeds

Clinical relevance

Light

Frequent occurrence

Possible occurence

Hazelnut; Kiwi; Rye flour

Pork

Clinical relevance

Medium

Frequent occurrence

Cat, domestic

Possible occurence

Potato

Clinical relevance

Light

Frequent occurrence

Possible occurence

Apple; Birch, weeping; Latex; Tomato

Ragweed pollen

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Apple; Banana; Cantaloupe; Chamomile tea; Honey; Honeydew; Nuts; Sunflower; Watermelon

Tomato

Clinical relevance

Light

Frequent occurrence

Birch, weeping; Peanut; Rye-grass; Timothy

Possible occurence

Apple; Celery; Latex; Mugwort; Potato

Walnut

Clinical relevance

Medium

Frequent occurrence

Possible occurence

Peach