Food allergies resulting from immunological cross-reactivity with inhalant allergens: Guidelines from the German Society for Allergology and Clinical Immunology (DGAKI), the German Dermatology Society (DDG), the Association of German Allergologists (AeDA) and the Society for Pediatric Allergology and Environmental Medicine (GPA)

Effects of Insect Consumption on Human Health: A Systematic Review of Human Studies

Insects have been consumed as food in diverse cultures worldwide, gaining recognition as a sustainable and nutritious food source. This systematic review aims to update information on the impact of insect consumption on human health based on human randomized controlled trials (RCTs) and allergenicity assessment studies. Following PRISMA guidelines, studies published in the last 10 years were analyzed. From one-thousand and sixty-three retrieved references, nine RCTs and five allergenicity studies were analyzed. Post-prandial amino acid levels increased after insect protein consumption. In comparison with other protein sources, insect protein showed no significant differences in the area under the curve (AUC) values for essential amino acids but tended to have lower peaks and peak later. In terms of muscle protein synthesis, there were no significant differences between insect protein and other protein sources. Glucose levels did not differ; however, insulin levels were lower after the consumption of insect-based products. The effects on inflammatory markers and microbiota composition were inconclusive and the studies did not show significant effects on appetite regulation. Allergenicity assessments revealed a sensitisation and cross-reactivity between insect allergens and known allergens. A partial reduction of cross-allergenicity was observed via thermal processing. Insect protein is an adequate protein source with promising health benefits; however, further research is needed to fully understand its potential and optimise its inclusion into the human diet.

Not Just a Banana: The Extent of Fruit Cross-Reactivity and Reaction Severity in Adults with Banana Allergy

This cross-sectional study aimed to investigate the prevalence and clinical characteristics of cross-reactivity and co-allergy to other plant foods among adult patients with IgE-mediated banana allergy in Thailand. A structured questionnaire was used to assess clinical reactivity, and cross-reactivity diagnoses were based on reactions occurring within 2 years of banana allergy onset, within 3 h of intake, and confirmed by allergists. Among the 133 participants, the most commonly associated plant foods with clinical reactions were kiwi (83.5%), avocado (71.1%), persimmon (58.8%), grapes (44.0%), and durian (43.6%). Notably, 26.5% of the reported reactions to other plant foods were classified as severe. These findings highlight the common occurrence of cross-reactivity/co-allergy to other plant foods in banana-allergic patients, with a significant proportion experiencing severe reactions. Travelers to tropical regions should be aware of this risk and advised to avoid specific banana cultivars and plant foods with reported high cross-reactivity. The inclusion of self-injectable epinephrine in the management plan for patients with primary banana allergy should be considered due to the substantial proportion of reported severe reactions and the wide range of clinical cross-reactivity and co-allergy observed.

Elicitors and phenotypes of adult patients with proven IgE-mediated food allergy and non-immune-mediated food hypersensitivity to food additives

BACKGROUND

Food allergy is a growing health concern with a prevalence of 2%-3% in the adult population in Europe. Non-immune-mediated food hypersensitivities, which include reactions after ingestion of food additives, affect 1% of adults and may resemble IgE-induced allergic reactions without identifiable immunologic sensitization. A double-blind placebo-controlled food challenge (DBPCFC) is the gold standard for the diagnosis of any food hypersensitivity.

OBJECTIVE

We analysed a large group of adult patients with suspected food hypersensitivity, who had undergone DBPCFC, to better understand IgE-mediated food allergy and non-immune-dependent food hypersensitivity to food additives in adults regarding elicitors, symptoms and positivity rates of oral challenges.

METHODS

Data from 541 patients with suspected food hypersensitivity were analysed, who underwent an oral food challenge between 2010 and 2019.

RESULTS

IgE-dependent food allergy was confirmed in 114 of 329 adult patients (34.6%). The confirmation rate was lower in the group of patients with suspected non-immune-mediated reactions to food additives (65 of 286, 22.7%). Urticaria and angioedema appeared more frequently in patients with IgE-mediated food allergies. By contrast, flush and diarrhoea were the most frequent symptoms after a challenge in the group with the non-immune-mediated reactions to food additives. Wheat and celery were the most frequently identified food allergens in adults, whereas colourings and preservatives were the most frequent elicitors of non-immune-mediated food hypersensitivity.

CONCLUSION

The importance of oral food challenges for the diagnosis of food hypersensitivity is confirmed. IgE-dependent food allergy is more frequently proven, reaching a positivity rate of one-third and only about 20% for non-immune-mediated hypersensitivity. Future studies should elaborate on the mechanisms of non-immune-mediated food hypersensitivity and the clinical impact of cofactors in this setting.

Follow-Up of a Rare Case of Eosinophilic Gastroenteritis Associated with Persistent Blood Eosinophilia and Multiple Food Allergies

Eosinophilic gastroenteritis (EGE) is a subgroup of the eosinophilic gastro-intestinal disorders (EGIDs), characterized by eosinophilic infiltration and chronic inflammation of the gastrointestinal tract. These are rare diseases with still incompletely elucidated causes and mechanisms, with frequently delayed diagnosis and variable outcome. Despite increased interest in eosinophilic diseases in recent years, fewer data have been published on EGE and no standardized diagnostic and therapeutic approach exists. This paper reports the case of a young male patient diagnosed with EGE in 2017 based on clinical and histopathological criteria and constantly monitored during five years. Besides gastrointestinal eosinophilic infiltration, biopsies also revealed eosinophilic infiltration of the oesophagus, despite no declared characteristic oesophageal symptoms. We found increased specific IgE to multiple foods and progressive blood hypereosinophilia which preceded EGE diagnosis by three years. The EGE management included selective dietary restrictions and pharmacologic therapy based on daily budesonide non-enteric coated tablets, proton pumps inhibitors, antihistamines, cromoglycate, correction of iron, calcium and vitamin D deficiencies. The clinical outcome was good, while blood eosinophilia and endoscopic appearance remained almost unchanged. After one year the patient complained of respiratory symptoms suggesting asthma, needing continuous combined inhaled therapy. The reported case is illustrative for complex presentation, diagnosis and outcome of a rare case of mucosal chronic EGE associated with oesophageal involvement, peripheral eosinophilia, multiple food allergies and asthma.

Clinical Relevance of Profilin Sensitization Concerning Oral Allergy Syndrome in Birch Pollen Sensitized Patients

Purpose

Many plant food allergens contain homologs to the major birch allergen Bet v 1; therefore, the majority of patients with birch pollen allergy suffer from oral allergy syndrome. We studied the relevance of sensitization of Bet v 1 and co-sensitization with profilin concerning the clinical manifestations of an oral allergy syndrome.

Patients and Methods

A total of 1119 patients with a positive skin prick test to birch and diagnostic for specific IgE to the allergen components Bet v 1 and profilin were analyzed retrospectively regarding complaints in the upper and lower airways, with demographic data as well as oral and gastrointestinal allergy symptoms.

Results

Patients with simultaneous specific IgE to the allergen components Bet v 1 and profilin have to deal more often with an oral allergy syndrome and intestinal reactions. They also suffer more frequently and severely from rhinitis symptoms and show a higher tendency for asthma. No increased number of systemic reactions was seen.

Conclusion

Patients with birch allergy recognizing both allergens have more probabilities of suffering from an oral allergy syndrome, and allergologists should be aware of this in order to give better advice to their patients.

Update of the S2k guideline on the management of IgE-mediated food allergies

Not available.

CCD Inhibition Test Can Improve the Accuracy of the Detection of Pollen and Seed Food Allergen-Specific IgE in Southern China

Objective

The presence of cross-reactive carbohydrate determinants (CCDs) may cause false-positive results in vitro allergen sIgE tests. In this paper, we focused on pollen sensitisation and its relationship with CCD in patients with respiratory allergic diseases in South China. A CCD inhibition test was conducted to assess whether patients were truly allergic to pollen or whether their sIgE was caused by a CCD cross-reaction, thus providing an important basis for clinical diagnosis and treatment.

Methods

Patients with known serologic pollen sensitization were selected, and sIgE of mugwort, tree mix 20 (willow/poplar/elm tree), common ragweed, Humulus scandens, peanut, soybean and CCD was detected via the EUROBlotMaster system. Thirteen CCD-sIgE negative patients and 33 CCD-positive patients were selected, and their serum samples were subjected to the CCD inhibition test.

Results

We found that 66.0% to 95.9% of patients sensitised to pollen and seed food allergens were co-sensitized to CCD. Additionally, 73.0% to 100% of the sIgE tests for pollen and seed food allergens turned negative after inhibition, mostly for allergens from Humulus scandens (100%, 15/15), followed by mugwort and peanut (85.2%, 23/27), ragweed (81.5%, 22/27), soybean (80.0%, 20/25), and tree pollen (73.0%, 19/26).

Conclusion

CCD causes false positives in the in vitro allergen sIgE tests of patients with respiratory allergic diseases in South China. Attention should be paid to the use of CCD inhibitors in diagnosing in vitro allergies because of their importance in diagnosing and treating local allergic diseases.

Lupine allergens: Clinical relevance, molecular characterization, cross-reactivity, and detection strategies

Lupine is commonly utilized as a technological food and ingredient in a great variety of processed products (snacks, bakery, meat, and dairy products) principally owing to its nutritional value and technological properties. However, its ingestion, even at trace amounts (in the range of mg protein per kg of food), can lead to severe adverse reactions in allergic individuals. Lupine belongs to the Leguminosae family, having the conglutins (α-, β-, δ-, and γ-) as allergens, among other proteins. Cross-sensitization of lupine-sensitized individuals with other legume species, mainly peanut, can occur, but the associated clinical reactivity is still unclear. The protection of the sensitized individuals should depend on an avoidance diet, which should rely on the compliance of food labeling and, as such, on their verification by analytical methods. Food processing, such as heat treatments, has an important influence on the structural properties of lupine proteins, altering their detectability and allergenicity. In this review, different aspects related with lupine allergy are described, namely, the overall prevalence, clinical relevance, diagnosis, and treatment. The characterization of lupine allergens and their potential cross-reactivity with other legumes are critically discussed. The effects of food matrix, processing, and digestibility on lupine proteins, as well as the available analytical tools for detecting lupine at trace levels in foods, are also herein emphasized.

Adverse reaction to Ficus Carica: reported case of a possible cross-reactivity with Der p1

Background

Ficus carica is an edible fruit, belonging to the Moraceae family, rarely described as cause of food allergy. We describe the first case of fig allergy that occurred as a cross-reactivity between fig and Derp 1.

Case presentation

We present a case of a 10-years-old-girl, with a history of no-seasonal mild intermittent rhinitis, who experienced an immediate reaction after ingestion of a fresh fig. Skin prick tests (SPT) with commercial extracts of food, airborne allergens, latex and panallergens (profilin, PR-10 and lipid transfer protein) were performed. SPT revealed a sensitization only for dermatophagoides farina and dermatophagoides pteronyssinus which was then confirmed with by specific IgE assay (UniCAP, Phadia, Uppsala, Sweden). We also carried out a positive SPT with a commercial fig allergen (Lofarma, Milan, Italy) and prick-by-prick (PBP) both with skin and pulp of green raw and cooked fig. Fig specific serum IgE levels were 1.08 U/ml and specific IgE for rDer p1 was 16.20 U/ml (total serum IgE = 377 U/ml). In contrast specific IgE levels for latex, LTP, profilin, PR-10 and pollen allergens were negative.

Conclusion

The ficin, the major fig allergen, belongs to cysteine protease family like Der p 1. The symptoms presented by our patient could be related to a cross reactivity between these two proteins which present a structural homology.

Production and Use of Recombinant Profilins Amb a 8, Art v 4, Bet v 2, and Phl p 12 for Allergenic Sensitization Studies

Four recombinant (r) allergens (rAmb a 8.0101, rArt v 4.0101, rBet v 2.0101, and rPhl p 12.0101) were successfully produced and used for sensitization studies. The allergens belong to the profilin family which is one of the most numerous allergen families. These four proteins represent allergens originating from pollen of weeds (rAmb a 8.0101 and rArt v 4.0101), tree (rBet v 2.0101) and grass (rPhl p 12.0101). The recombinant allergens were characterized using various biochemical and biophysical methods and tested for their ability to bind patient-derived antibodies. One hundred patients aged 2 to 50 years sensitized to pollen and plant-derived food allergens (IgE > 0.35 kU/L) were included. Sensitization to individual allergen sources and components of birch and timothy pollens was evaluated using multiparameter immunoblots. The presence of IgE to pollen-derived recombinant profilins rAmb a 8.0101, rArt v 4.0101, rBet v 2.0101, and rPhl p 12.0101 in serum was evaluated using ELISA method. The presence of IgE against pollen profilins was detected in 20 out of 100 studied patients. High correlation was seen between IgE ELISA results with individual pollen profilins. In summary, it was shown that the recombinant versions of the four allergenic profilins can be used for sensitization studies and for component-resolved allergy diagnostics.

The Application of Pollen as a Functional Food and Feed Ingredient-The Present and Perspectives

Pollen is recognized as an excellent dietary supplement for human nutrition, which is why it can be found in different forms on the market (granules, capsules, tablets, pellets, and powders). But, the digestibility of pollen’s nutrients is strongly affected by the presence of a pollen shell, which can decrease the bioavailability of nutrients by 50% and more. Since consumers have become more aware of the benefits of a healthy diet and the necessity to improve pollen digestibility, different pollen-based functional food products have been developed and extensive studies were done to estimate the beneficial effects of pollen-based feed on animal growth, health, and rigor mortise stage. Considering the positive effects of pollen nutrients and phytometabolites on human and animal health, the aim of this paper was to give an overview of recent achievements in the application of pollen in the formulation of functional food and animal diets. Special attention was paid to the effects of pollen’s addition on the nutritional, functional, techno-functional, and sensory properties of the new formulated food products. Anti-nutritional properties of pollen were also discussed. This review points out the benefits of pollen addition to food and feed and the possible directions in the further development of functional food and feed for the wellbeing of everyone.

Food Allergy in Adults: Substantial Variation in Prevalence and Causative Foods Across Europe

BACKGROUND

According to the community-based EuroPrevall surveys, prevalence of self-reported food allergy (FA) in adults across Europe ranges from 2% to 37% for any food and 1% to 19% for 24 selected foods.

OBJECTIVE

To determine the prevalence of probable FA (symptoms plus specific IgE-sensitization) and challenge-confirmed FA in European adults, along with symptoms and causative foods.

METHODS

In phase I of the EuroPrevall project, a screening questionnaire was sent to a random sample of the general adult population in 8 European centers. Phase II consisted of an extensive questionnaire on reactions to 24 preselected commonly implicated foods, and measurement of specific IgE levels. Multiple imputation was performed to estimate missing symptom and serology information for nonresponders. In the final phase, subjects with probable FA were invited for double-blind placebo-controlled food challenge.

RESULTS

Prevalence of probable FA in adults in Athens, Reykjavik, Utrecht, Lodz, Madrid, and Zurich was respectively 0.3%, 1.4%, 2.1%, 2.8%, 3.3%, and 5.6%. Oral allergy symptoms were reported most frequently (81.6%), followed by skin symptoms (38.2%) and rhinoconjunctivitis (29.5%). Hazelnut, peach, and apple were the most common causative foods in Lodz, Utrecht, and Zurich. Peach was also among the top 3 causative foods in Athens and Madrid. Shrimp and fish allergies were relatively common in Madrid and Reykjavik. Of the 55 food challenges performed, 72.8% were classified as positive.

CONCLUSIONS

FA shows substantial geographical variation in prevalence and causative foods across Europe. Although probable FA is less common than self-reported FA, prevalence still reaches almost 6% in parts of Europe.

Precision medicine allergy immunoassay methods for assessing immunoglobulin E sensitization to aeroallergen molecules

Molecular-based allergy diagnosis for the in vitro assessment of a patient immunoglobulin E (IgE) sensitization profile at the molecular level uses allergen molecules (also referred to as allergen components), which may be well-defined, highly purified, natural allergen components or recombinant allergens. Modern immunoassay methods used for the detection of specific IgE against aeroallergen components are either singleplex (such as the fluorescence enzyme immunoassay with capsulated cellulose polymer solid-phase coupled allergens, the enzyme-enhanced chemiluminescence immunoassay and the reversed enzyme allergosorbent test, with liquid-phase allergens), multiparameter (such as the line blot immunoassay for defined partial allergen diagnostics with allergen components coating membrane strips) or multiplex (such as the microarray-based immunoassay on immuno solid-phase allergen chip, and the two new multiplex nanotechnology-based immunoassays: the patient-friendly allergen nano-bead array, and the macroarray nanotechnology-based immunoassay used as a molecular allergy explorer). The precision medicine diagnostic work-up may be organized as an integrated “U-shape” approach, with a “top-down” approach (from symptoms to molecules) and a “bottom-up” approach (from molecules to clinical implications), as needed in selected patients. The comprehensive and accurate IgE sensitization molecular profiling, with identification of the relevant allergens, is indicated within the framework of a detailed patient’s clinical history to distinguish genuine IgE sensitization from sensitization due to cross-reactivity (especially in polysensitized patients), to assess unclear symptoms and unsatisfactory response to treatment, to reveal unexpected sensitizations, and to improve assessment of severity and risk aspects in some patients. Practical approaches, such as anamnesis molecular thinking, laboratory molecular thinking and postmolecular anamnesis, are sometimes applied. The component-resolved diagnosis of the specific IgE repertoire has a key impact on optimal decisions making for prophylactic and specific immunotherapeutic strategies tailored for the individual patient.

Dietary Interventions in Pollen-Related Food Allergy

In practice, it remains unclear what the best dietary approach is in subjects with pollen-related food allergy (PRFA). Our objective was to evaluate the effect of (1) dietary avoidance advice, (2) oral immunotherapy (OIT), (3) (heat) processing, and (4) consumption of hypoallergenic cultivars on frequency, severity, and eliciting dose of pollen-related food allergic reactions. A systematic search was conducted in PubMed, Embase, and Cochrane. All studies performing an in vivo investigation of one of the four interventions in adults with PRFA were included. Each study was assessed for quality and validity. Available data on frequency, severity, and eliciting dose of allergic reactions were extracted. Ten studies matched the eligibility criteria. No studies were retrieved on dietary avoidance advice. Two studies (N = 92) on apple OIT reported that tolerance was induced in 63% and 81% of subjects. Four studies (total N = 116) focused on heat processing. Heating was found to completely eradicate symptoms in 15–71% of hazelnut allergic and 46% of celery allergic individuals. Four studies (N = 60) comparing low to high allergenic apple cultivars revealed that Santana (and possibly Elise) apples seemed to cause milder reactions than Golden Delicious. In the awareness that overall level of evidence was low, we conclude that OIT, heat processing, and hypoallergenic cultivars may diminish or completely prevent allergic reactions in some but not all subjects with PRFA.

Plant food allergy: Influence of chemicals on plant allergens

Plant-derived foods are the most common allergenic sources in adulthood. Owing to the rapidly increasing prevalence of plant food allergies in industrialized countries, the environmental factors are suspected to play a key role in development of allergic sensitization. The present article provides an overview of ways by which chemicals may influence the development and severity of allergic reactions to plant foods, with especial focus on plant allergens up-regulated under chemical stress. In plants, a substantial part of allergens have defense-related function and their expression is highly influenced by environmental stress and diseases. Pathogenesis-related proteins (PR) account for about 25% of plant food allergens and some are responsible for extensive cross-reactions between plant-derived foods, pollen and latex allergens. Chemicals released by anthropogenic sources such as agriculture, industrial activities and traffic-related air pollutants are potential drivers of the increasing sensitization to allergenic PRs by elevating their expression and by altering their immunogenicity through post-translational modifications. In addition, some orally-taken chemicals may act as immune adjuvants or directly trigger non-IgE mediated food allergy. Taken together, the current literature provides an overwhelming body of evidence supporting the fact that plant chemical exposure and chemicals in diet may enhance the allergenic properties of certain plant-derived foods.

Glycans and glycan-specific IgE in clinical and molecular allergology: Sensitization, diagnostics, and clinical symptoms

Glycan-specific IgE antibodies cross-react with highly similar or even identical carbohydrate structures on a variety of different natural allergens, the so-called cross-reactive carbohydrate determinants (CCDs). In clinical practice CCDs often interfere with the specificity of in vitro allergy diagnostics, thus impairing allergy therapy decisions for individual patients. Strikingly, these IgE antibodies directed against CCDs often do not cause clinically relevant allergy symptoms. On the other hand, the IgE-binding glycan allergen galactose-α-(1,3)-galactose (α-Gal) is associated with IgE-mediated delayed anaphylaxis in meat allergy. The reason for this discrepancy is not known. The discovery of α-Gal stimulated new discussions and investigations regarding the relevance of anti-glycan IgE for allergic diseases. In this review the effect of glycans and glycan-specific IgE on sensitization to allergens and allergy diagnosis is described. Because parasite infections elicit a similar immunologic environment as allergic diseases, the association of glycan-specific antibodies against parasite glycoproteins with glycan structures on allergens is discussed.

[Risk hidden in the small print? : Some food additives may trigger pseudoallergic reactions]

Some food additives may trigger pseudoallergenic reactions. However, the prevalence of such an overreaction is - despite the increasing number of food additives - rather low in the general population. The most common triggers of pseudoallergic reactions to food are naturally occurring ingredients. However, symptoms in patients with chronic urticaria should improve significantly on a pseudoallergen-free diet. In addition, some studies indicate that certain food additives may also have an impact on the symptoms of patients with neurodermatitis and asthma.

[Food Allergy and Intolerance : Distinction, Definitions and Delimitation]

Immunologically mediated hypersensitivity to foods is defined as food allergy, mainly due to immunglobulins of class E (IgE) triggering immediate reactions (type I hypersensitivity) with possible involvement of mucosa, skin, airways, intestinal tract, and the vascular system. Primary food allergy is based on (early) IgE sensitization against animal (e. g., cow's milk, hen's eggs) or plant proteins (e. g. peanut, hazelnut or wheat). In the case of secondary food allergies, IgE against pollen proteins (e. g., birch) reacts to structurally related food proteins (with cross-reactions to stone and pit fruits). Non-immunological food intolerance reactions are mostly based on carbohydrate malassimilation (e. g., lactose intolerance, fructose malabsorption) and are rarely due to pseudo-allergies (e. g., flavors, dyes, preservatives) primarily in patients with chronic urticaria. Common intestinal symptoms are mainly due to functional disorders (e. g., irritable bowel disease), rarely because of inflammatory intestinal diseases (e. g., celiac disease). Histamine intolerance, gluten hypersensitivity, and so-called food type III hypersensitivities are controversial diagnoses. The aforementioned disease entities/models are of variable importance for the affected individuals, the public health system, and society in general.

[Mucosal diseases from an allergological perspective]

The oral allergy syndrome is one of the most common form of food allergy and manifests as contact urticaria of the oral mucosa after consumption of cross reacting foods. Whereas allergic contact stomatitis often occurs due to dental materials, allergic contact cheilitis is usually a reaction due to topical therapeutics like herpes ointments or lip care products. As late type reactions are more frequent than immediate type reactions in the anogenital mucosa, contact dermatitis in this area should be identified via epicutaneous testing. In case of contact urticaria at the genital mucosa, a semen allergy or a latex allergy should be given due consideration as a possible cause. Angioedemas, which are mostly common histamine mediated, usually prefer skin areas with loose connective tissue such as the oral or genital mucosa. Fixed drug eruption also occurs preferentially in these areas. Bullous drug-induced skin reactions (e.g., SJS and TEN) are characterized by severe hemorrhagic, erosive affections of mucous membranes.

How relevant is panallergen sensitization in the development of allergies?

Panallergens comprise various protein families of plant as well as animal origin and are responsible for wide IgE cross-reactivity between related and unrelated allergenic sources. Such cross-reactivities include reactions between various pollen sources, pollen and plant-derived foods as well as invertebrate-derived inhalants and foodstuff. Here, we provide an overview on the most clinically relevant panallergens from plants (profilins, polcalcins, non-specific lipid transfer proteins, pathogenesis-related protein family 10 members) and on the prominent animal-derived panallergen family, tropomyosins. In addition, we explore the role of panallergens in the sensitization process and progress of the allergic disease. Emphasis is given on epidemiological aspects of panallergen sensitization and clinical manifestations. Finally, the issues related to diagnosis and therapy of patients sensitized to panallergens are outlined, and the use of panallergens as predictors for cross-reactive allergy and as biomarkers for disease severity is discussed.

Allergy--current insights into prevention and diagnostic workup of immediate-type allergy and treatment of allergic rhinoconjunctivitis

In recent decades, the incidence of allergic diseases has dramatically increased, by now affecting a large percentage of the population. For a long time, allergen avoidance was considered the most crucial measure in primary allergy prevention. However, studies have increasingly shown that exposure to allergens is an essential prerequisite for the development of immunological tolerance. Diagnostic workup is based on patient history, skin tests, and measurement of specific IgE antibodies. The introduction of component-based diagnostic workup offer an option to differentiate between primary sensitization and cross-reactivity caused by sensitization to panallergens or sensitization to cross-reactive carbohydrate epitopes. Symptomatic treatment only leads to temporary relief of allergic symptoms. By contrast, specific immunotherapy (SIT) may have long-lasting therapeutic effects and potentially even result in a complete cure. The selection of allergens for SIT is guided by the principle of major allergens. It is recommended to use those preparations that have been proven safe and effective in controlled clinical studies. With respect to subcutaneous immunotherapy, a host of tested and approved extracts are available for a wide range of different allergens. Large clinical trials have also confirmed the efficacy of sublingual immunotherapy with grass and also birch pollen extracts, which has led to the official approval of some preparations containing these allergens.