Food allergy T78.1

Author: Prof. Dr. med. Peter Altmeyer

Co-Autor: Dr. med. Rainer Stengel

All authors of this article

Last updated on: 22.10.2022

Dieser Artikel auf Deutsch


Allergy to food; Birch pollen-nut-nut pome fruit syndrome; Food allergy; Food allergy primary; Food allergy secondary; gastrointestinal allergy; NMA; Trophallergy

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Frequently occurring, inflammatory, IgE-mediated or IgE-independent, local (gastrointestinal) or systemic reaction (e.g. urticaria, angioedema, asthma, rhinitis, etc.) to food itself or to food additives.

In contrast to this are the non-immunological food int olerances (NMU), the intolerances in the narrower sense (e.g. lactose intolerance, pseudoallergic reactions to salicylates, toxic or infectious causes, biogenic amines) or food intoxications.

It is not uncommon for food allergies to occur only in the presence of multiple co-factors:

Food is responsible for 1/3 of all threatening anaphylactic reactions, in children even in 50% (Jäger L et al. 2001). In the USA, it is estimated that there are about 400 deaths/year. The most important causes are:

  • Peanuts
  • Tree nuts
  • Fish
  • Seafood
  • Legumes
  • Milk
  • Hen's egg
  • Seeds (linseed, sesame)
  • Fruit (kiwi)
  • Cereals.

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Food allergies (NMA) can be divided into 4 groups and some subgroups according to pathogenetic aspects (see alsoFood allergens):

IgE-mediated food allergies are divided into 3 types according to Pichler:

  • Type A (about 5-10% of patients): Occurs in infancy. Sensitization occurs via the gastrointestinal tract with relatively stable allergens. Proteins from milk (see below cow's milk allergy), egg, fish, peanut, hazelnut and soya are the most important allergens. As oral tolerance matures, the allergy (in about 80% of patients) recedes.
  • Type B - or secondary food allergy (about 75%): Occurs in adolescents and adults. It is the most common form of allergy in Central Europe. Sensitization is via the respiratory tract (gastrointestinal tolerance is already more stable at this age!). Aerogenic allergens trigger the formation of IgE (e.g. pollen, latex), which cross-react with similar proteins in food. Patients usually have only mild symptoms, e.g. an oral allergy syndrome (see below allergy syndrome, oral = OAS).
  • Type C - also primary food allergy (about 15% of patients): Primarily in "non-atopic" adult women who neither suffered from NMA in childhood nor were respiratory sensitized later. Sensitization occurs in the GI tract to relatively digestible proteins (e.g. chicken meat, crustaceans (see below crustacean allergy), fish (see below fish allergy), egg (see below hen's egg), milk (see below cow's milk) and various types of food. Meat (see meat allergy) as well as vegetable allergens like peanut, kiwi, fig, carrot and curry).

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Incidence data vary considerably depending on the source. The subjectively perceived food intolerance is 20-30%.

In meta-analyses the following incidence figures of immunologically mediated food allergies are mentioned:

  • 4.2% of children (relevant allergens: chicken protein, milk protein, soya, wheat and in recent years peanut; the frequency of peanut allergy has tripled in recent decades)
  • 3.7% of adults (relevant allergens: wheat, celery, carrot, nuts, pome and stone fruit, crustaceans and shellfish).

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People with food allergies are more common among the urban population and are more likely to be female.

Clinical features
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Skin manifestations are common (50% of cases), possibly combined with allergic symptoms of the gastrointestinal tract and respiratory tract (about 20% of cases). Cardiovascular symptoms present in 10-15% of affected individuals.

After food ingestion, dysesthesias of the tongue are most commonly reported (35% of cases), followed by gastrointestinal symptoms (24%), erythema or pruritus (18%), urticaria (15%), rhinoconjunctivitis (12%), dyspnea (9%), eczema (6%), headache (5%), and anaphylaxis (0.3%).

Immediate type reactions due to food (according to Werfel):

  • Mucocutaneous symptoms (most common):
  • Eyes:
    • Itching
    • Redness
    • lacrimation
    • periorbital edema
  • Gastrointestinal symptoms:
    • nausea
    • vomiting
    • Diarrhea
  • Respiratory symptoms:
    • nasal congestion
    • rhinitis
    • Laryngeal edema
    • Hoarseness
    • bronchial allergic asthma
  • Anaphylactic circulatory reaction.

Symptoms of delayed reaction or chronic exposure (var. n. Worm)

  • Nausea
  • Vomiting
  • Abdominal pain
  • Gastroesophageal reflux
  • Inappetence
  • Diarrhea
  • Blood in stool
  • Failure to thrive
  • Food protein-induced enterocolitis syndrome in infants and young children (FPIES)
  • Food protein-induced enteropathy in infants, young children and adults

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Elicitation of the triggering substance by specific, precise anamnesis and, if necessary, record keeping.

Prickand scratch test of the suspected food with ready-made preparations or native (see also prick-to-prick test; atopy patch test).

Prick-block testing is performed if there is no specific indication for a possible sensitisation in the case of a suspected food allergy. The following are tested: apple, tree nuts, peanut, fish (cod), hen's egg, carrot, crustaceans (shrimps; only recommended for adults), milk, celery, sesame, soy, wheat.

Determination of specific IgE in the blood with CAP system or RAST. Here, in addition to the screening test, the single-cell allergens are tested.

Epicutaneous testing with native foods in infants has a high specificity and sensitivity, but is not yet a routine test in adults.

Testing by means of a targeted oral provocation test (gold standard: double-blind, placebo-controlled oral food provocation).

If necessary under stationary conditions:

  • Oligo-allergenic diet (e.g. potato-rice diet in adults, extensively hydrolysed protein preparations in infants).
  • Elimination diet (targeted omission of suspicious foods), at least for 7 days. In case of improvement, follow up with oral provocation.

Testing for dyes and preservatives first by capsule and then, under emergency conditions, by provocation testing through the original food.

Contraindication of provocation testing: life-threatening anaphylactic reactions in the anamnesis. Use of ß-blockers or ACE-inhibitors.

General information: In children, the results are only valid for 12 months, after which the test must be repeated. Patients must be free of symptoms at the time of testing and have sufficient time to take immunomodulatory medication: 3-5 days for systemic glucocorticoids or 5 days for systemic antihistamines.

Differential diagnosis
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Pseudoallergic reactions (additives, histamine intolerance)

Metabolic diseases (enzyme deficiency - e.g. lactose intolerance; fructose malabsorption)

Immunological diseases (e.g. celiac disease as gluten-sensitive enteropathy)

Intoxications (bacterial or other toxins e.g. phytoplankton [see below crustacean allergy])

Projection, aversion (most frequent differential diagnoses)

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Food allergies sometimes manifest themselves only during exertion, or exacerbate under exertion (see below: exertion urticaria). In such cases, it is difficult to take a medical history, as food consumed up to 6 hours before may be responsible for the allergic reaction.

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Therapy is based on the one hand on short-term (symptomatic) treatment of acute reactions, and on the other hand on long-term strategies to prevent the risk of recurrences (avoidance strategies with training and dietary programmes). New perspectives for achieving clinical tolerance seem to be offered by sublingual or oral immunizations.

General therapy
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Leave of absence: Apart from the emergency intervention for acute food allergy, the targeted (allergen) leave is the most important preventive element of a therapy. This requires a subtle and reliable diagnosis. This requires not only proof of sensitization, but also proof of clinical relevance. Here there is a need for professional advice (nutritionist). Special attention must be paid to allergens that lead to potentially severe anaphylactic reactions (see below food allergens)

Procedure after maternity leave: Recommendations for re-exposure after maternity leave are based on observations of the spontaneous course of the disease (see, for example, cow's milk allergy, chicken egg protein allergy, fish allergy, peanut allergy). It is particularly appropriate for children after 2 years of allergen-free periods under stationary surveillance.

Nutritional therapy: Due to the complexity of the individual sensitizations (heat-labile, heat-stable, cross-reactions (see also lipid transfer proteins), type of immunological response), a detailed dietary plan with avoidance strategy and advice on a sensible use of nutrition is absolutely necessary.

If necessary, emergency drug therapy according to the stages of anaphylactic shock. S.u. shock, anaphylactic.

Specific immunotherapy: As the study situation for immunotherapy in pollen-associated food allergies (e.g. immunotherapy for birch pollen-associated apple allergy) is unclear, immunotherapy is only recommended if allergic respiratory symptoms are present at the same time.

External therapy
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For type IV reactions with outbreak or worsening of eczema, see below eczema.

Internal therapy
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  • Acute therapy: In acute type I symptoms, therapy according to the stages of anaphylactic shock. See below Shock, anaphylactic.
  • In food allergies where the allergen is difficult to avoid (e.g. milk, wheat), prophylactic administration of disodium cromoglicic acid (e.g. Colimune) may be given. Adults and adolescents receive 200 mg 4x/day as permanent medication.

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  • Data on the course show that early childhood milk protein allergy has a good prognosis in terms of spontaneous tolerance development. This natural course is also observed with other allergens. It is strongly dependent on the food source. In addition to cow's milk allergy, allergic patients to chicken protein, wheat and soy tend to experience spontaneous remission in the first years of life.
  • Peanut and tree nut, fish and crustacean allergies persist into adulthood.
  • High specific IgE levels often correlate with clinical relevance and rarely tend to develop tolerance.
  • IgE antibodies to food allergens may rise or fall during the course. The drop is often associated with tolerance development.
  • Food allergies in adulthood may represent persistence of a childhood form or be a de novo development.
  • For preventive measures see below. Allergy prevention.

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  • Lifelong avoidance of the triggering substance. In cases of confirmed food allergy, the targeted elimination diet is the only intervention whose effect has been proven to be effective. In some cases, the food is tolerated again after several months of abstinence, but in type I reactions, renewed provocations are always associated with a risk. Peanut (usually a lifelong allergen) is the most common cause of severe to fatal anaphylactic reactions. Fish allergens also have a pronounced allergenicity (aerogenic transmission!).
  • Fruit sensitization is frequently coupled with pollen allergies. Specific immunotherapy against pollen allergens is accompanied by an improvement in food tolerance in the majority of cases. Specific immunotherapies directly with food (e.g. peanuts, hazelnuts) have so far had many side effects and need to be further investigated in controlled long-term studies.
  • Notice. The legal directive (Directive 2003/89/EC amending Directive 2000/13/EC of 25.11.2003 and the update of 22.12.2006) defines allergenic foods that are subject to declaration.

  • The declaration is obligatory for eggs, peanuts, fish, crustaceans, lupine, milk (incl. lactose), nuts (hazelnuts, almonds, etc.), molluscs (mussels, squid), celery, mustard, sesame seeds, soy, sulphur dioxide and sulphite from 10 mg/kg food, cereals containing gluten.
  • Instead of the usual class names (e.g. vegetable oil, fruits, spices, vegetables or natural flavourings), the individual ingredients must be listed in future if the food class accounts for more than 2% of the product or if it contains ingredients from the above-mentioned list. However, these regulations do not apply to loose, unpacked products.
  • Heating can eliminate some allergens. Allergens of animal origin tend to be thermostable, while plant allergens tend to be thermolabile.
  • Patients with anaphylactic reactions with respiratory and circulatory involvement, those with a clearly defined trigger that cannot be completely avoided, and those with a greatly increased risk of developing anaphylaxis (e.g. Adults with mastocytosis, children with high peanut sensitisation) should carry an emergency kit containing an antihistamine (e.g. Fenistil drops), a systemic glucocorticoid (e.g. Celestamine 0.5 liquidum) and an adrenaline autoinjector as a precaution.

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Common food allergens in Germany

Share (%)

occurrence of anaphylactic reactions










Nuts and peanuts









Alcoholic beverages









Food additives and their E-numbers (food allergy)


EEC number


EEC number

Lactoflavin (riboflavin)

E 101

Sorbic acid

E 200


E 160a

Sodium sorbate

E 201

Sugar caramel

E 150

Potassium sorbate

E 202


E 174

Calcium sorbate

E 203


E 175

Benzoic acid

E 210


E 100

Sodium benzoate

E 211


E 102

Potassium benzoate

E 212

Quinoline Yellow

E 104

Calcium benzoate

E 213


E 106

para-Hydroxibenzoic acid ethyl ester (PHB ethyl ester)

E 214

Yellow orange S

E 110

Sodium salt of PHB ethyl ester (E 214)

E 215

Real carmine (carminic acid, cochineal)

E 120

para-Hydroxibenzoic acid n-propyl ester

E 216

para-Hydroxibenzoic acid n-propyl ester sodium compound

E 217


E 122

para-hydroxybenzoic acid methyl ester

E 218


E 123

para-Hydroxibenzoic acid methyl ester sodium compound

E 219

Cochineal red A (Ponceau 4 R)

E 124

sulphur dioxide, sulphurous acid

E 220


E 127

Sodium sulphite

E 221

Patent blue V

E 131

Indigotine I (indigo carmine)

E 132

Sodium hydrogen sulphite

E 222


E 140

Copper-containing complexes of chlorophylls and chlorophyllins

E 141

Brilliant acid green BS (Lisamine green)

E 142


EEC number


EEC number

Brilliant black BN

E 151

Sodium bisulfite

E 222

Carbo medicinalis vegetabilis

E 153

Sodium disulfite (sodium pyrosulfite or sodium metabisulfite)

E 223

carotene, alpha-carotene, gamma-carotene

E 160a

Potassium disulfite (potassium pyrosulfite or potassium metabisulfite)

E 224

Bixin, Norbixin (Annatto, Orlean)

E 160b

Calcium sulphite

E 226

capsanthin, capsorubin

E 160c

Calcium hydrogen sulphite

E 227


E 160d

Formic acid

E 236


E 160e

Sodium Formate

E 237

beta-apo-8-carotenic acid ethyl ester

E 160f

Calcium formate

E 238

Propionic acid

E 280


E 161

Sodium propionate

E 281


E 161a

Calcium propionate

E 282


E 161b

Potassium propionate

E 283


E 161c

Biphenyl (diphenyl)

E 230


E 161d

Orthophenylphenol or sodium orthophenylphenolate

E 231


E 161e


E 161f


E 232


E 161g


E 233

beetroot, betanin

E 162


E 163


E 173

Calcium carbonate

E 170

Titanium dioxide

E 171

Iron oxides and hydroxides

E 172

Propyl gallate

E 310

Octyl gallate

E 311

Ammonium alginate

E 403

Dodecyl gallate

E 312

Potassium alginate

E 402

Butylhydroxianisole (BHA)

E 320

Sodium alginate

E 401

butylhydroxituluene (BHT)

E 321



Ascorbates (salts of L-ascorbic acid)

E 300


E 422

Sodium carbonate


Sodium L-ascorbate

E 301

Sodium hydrogen carbonate


Potassium L-ascorbate


Sodium sulphate


Calcium L-ascorbate

E 302


E 440

Citrates (salts of citric acid)


E 420

Citric acid

E 330

Hard paraffin


Sodium citrates

E 331

Magnesium stearate


Potassium citrates

E 332

Ethyl cellulose


Calcium citrates

E 333

Benzyl alcohol


Lactates (salts of lactic acid)



Lactic acid

E 270



Sodium lactate

E 325

Lactic acid ethyl ester


Potassium lactate

E 326



Calcium lactate

E 327

6-Palmitoyl-L-Ascorbic acid

E 304


E 322


E 407

Mono- and diglycerides of fatty acids esterified with citric acid

E 472c

Guar (guar gum)

E 412

Orthophosphates (salts of orthophosphoric acid)

Tragacanth (Tragacanth gum)

E 413

Sodium orthophosphates

E 339

gum arabic

E 414

Potassium orthophosphates

E 340

Calcium orthophosphates

E 341

6-palmitoyl-L-ascorbic acid

E 304

Tartrates (salts of L (+) tartaric acid

E 334

Unintended ingredients

Sodium tartrate

E 335

Detergents and disinfectants

Potassium tartrate

E 336

Formalin, chloramine, p-chlorobenzoic acid

Potassium sodium tartrate

E 337

Detergents and disinfectants


dichlorophen, hexachlorophene, quaternary

, synthetic

E 303

Ammonium compounds, iodophores

, synthetic

E 309

tocopherol acetate


extracts of natural origin with high tocopherol content

E 306

alpha-tocopherol, synthetic

E 307

beta-tocopherol, synthetic


Inhalation allergen

Food allergen


tree pollen

apple, hazelnut, carrot, potato, cherry, kiwi, nectarine, peach, celery, soy


Mugwort pollen

spices, carrot, lychee, mango, celery, sunflower seeds, grape


Natural Latex

pineapple, avocado, banana, potato, kiwi, tomato


ficus benjamina



grass and cereal pollen

Flours, bran, tomato, pulses


House dust mite

Crustaceans and molluscs



Apricot, plum, apple, salad


Animal Epidermis

cow's milk, meat, offal


Grapevine pollen (ragweed pollen, ragweed pollen)

melon, zucchini, cucumber, banana


Bird Allergen

egg, poultry meat, offal


Thermolability of food


conditionally heat-stable


Vegetable allergens

peanut, celery, tomato, spices (plural)

Soya, cereals, potatoes, sunflower seeds, poppy seeds

carrot, eggplant, apple, peach, apricot, plum, strawberry, banana

Animal Allergens

cow's milk, hen's egg, fish, crustaceans

beef, pork, lamb, game

Diet/life habits
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Supplementary food should be given to children with an increased risk of allergy between the 5th and 7th month of life, including the feeding of more allergenic foods. Then the chance of tolerance development is higher. Full breastfeeding for 4 months is recommended for this risk group, although longer breastfeeding is not harmful.

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In recent years, there is increasing evidence that food allergies can also be acquired through the skin (Tamagawa-Mineoka R et al. 2018). For example, patients who used soaps containing oat and almond relatives developed dysphagia and diarrhea after consuming foods containing cereals. A similar situation has been reported with corn products (soaps).

Case report(s)
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  • 55-year-old female patient with 5 years of allergic rhinoconjunctivitis during the spring months. Proven sensitization to birch, alder and hazel pollen (see below tree pollen). A specific immunotherapy (hyposensitization therapy) with tree pollen carried out over 4 years led to a complete improvement of the clinical symptoms.
  • Recently itching of the oral mucosa when eating hazelnuts. Testing: Prick test with a commercial hazelnut extract and prick-to-prick test with raw hazelnuts positive. Detection of specific IgE on hazelnut ( RAST class 3).
  • Double-blind placebo-controlled provocation with hazelnut: Tingling with swelling of the lips and tongue when a hazelnut pudding is taken. 4 hours later severe rhinoconjunctivitis persisting for 24 hours.
  • Dg. Oral allergy syndrome to hazelnut.

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Last updated on: 22.10.2022