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In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources., (© 2023 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Background: Cow's milk (CM) and hen's egg (HE) are leading triggers of anaphylaxis in early childhood. The aim of this study was to identify clinical phenotypes and therapeutic measures for CM anaphylaxis (CMA) compared to HE anaphylaxis (HEA) in children up to 12 years of age, based on a large pan-European dataset from the European Anaphylaxis Registry., Methods: Data from 2007 to 2020 on clinical phenotypes and treatment from 10 European countries, as well as Brazil, were analysed. The two-step cluster analysis was used to identify the most frequent phenotypes. For each trigger, three clusters were extracted based on sex, age, and existence of symptoms in four vitally important systems., Results: Altogether 284 children with CMA and 200 children with HEA were identified. They were characterised as male (69% vs. 64%), infants (65% vs. 61%), with a most frequent grade III of Ring&Messmer classification (62% vs. 64%), in CMA versus HEA, respectively. Respiratory symptoms occurred more often in CMA (91% vs. 83%, p = 0.010), especially in infants (89% vs. 79%, p = 0.008). Cardiovascular symptoms were less frequent in CMA (30% vs. 44%, p = 0.002), in both infants (33% vs. 46%, p = 0.027), and older children (25% vs. 42%, p = 0.021). The clusters extracted in the CMA group were characterised as: (1) mild dermal infants with severe GI (40%), 2. severe dermal (35%), 3. respiratory (25%). While in HEA group: 1. infants with severe GI and/or reduction of alertness (40%), (2) conjunctival (16%), (3) mild GI without conjunctivitis (44%). The severity of the reaction was independent from the amount of ingested allergen protein, regardless of trigger. The first-line adrenaline application differed between the countries (0%-92%, as well as the reasons for not administering adrenaline, p < 0.001)., Conclusions: Despite the similarity of their age, sex, and severity grade, the clinical profiles differed between the CMA and HEA children. Adrenaline was underused, and its administration was country dependent. Further studies are needed to assess to what extent the differences in the clinical profiles are related to matrix and/or absorption effects, and/or the allergen itself., (© 2023 The Authors. Clinical and Translational Allergy published by John Wiley & Sons Ltd on behalf of European Academy of Allergy and Clinical Immunology.)

Introduction: Delayed allergy to red meat, also termed alpha-gal syndrome, is increasingly reported in adults and African communities, while pediatric cases remain rare., Case Presentation: Here, we report on a 7-year-old Caucasian boy presenting with recurrent wheals since the age of 5 years old. Episodes with hives occurred around every 3 weeks, mainly in the evening. One of these episodes was also associated with angioedema. No clear trigger was identified. At the first visit, after excluding an infection and autoimmune thyroiditis, chronic spontaneous urticaria was suspected and symptomatic treatment with antihistamines was prescribed. Six months later, the boy presented at the emergency room with generalized urticaria, dyspnoea, and emesis. Symptoms resolved after administration of epinephrine and antihistamines. A detailed medical history after this event revealed that he had eaten three sausages as well as jelly beans containing gelatine several hours prior to this episode. More precisely, after eating the sausages and jelly beans during the day, he had shown some hives before going to bed, and later developed the other symptoms in the middle of the night, suggesting alpha-gal syndrome. In his history, several tick bites are reported. Immunoglobulin E levels for alpha-gal were clearly elevated, confirming the diagnosis of a delayed-appearing immunoglobulin E-mediated allergic reaction to alpha-gal. Emergency medication was prescribed and avoidance of red meat and gelatine-containing foods was recommended. Under this exclusion diet, the boy remained asymptomatic, with the exception of two accidents in the follow up of 3 years, one developing during a barbecue and the second after exceptionally eating marshmallows., Conclusion: A detailed clinical history led to the diagnosis of alpha-gal syndrome. Although alpha-gal syndrome is typically seen in adults, our case illustrates that children can also present with this potentially life-threatening allergy. Since alpha-gal syndrome is rare in Europe, the disease is not well known and often overlooked for several years, especially in children., (© 2023. The Author(s).)

Background: Anaphylaxis, which is rare, has been reported after COVID-19 vaccination, but its management is not standardized., Method: Members of the European Network for Drug Allergy and the European Academy of Allergy and Clinical Immunology interested in drug allergy participated in an online questionnaire on pre-vaccination screening and management of allergic reactions to COVID-19 vaccines, and literature was analysed., Results: No death due to anaphylaxis to COVID-19 vaccines has been confirmed in scientific literature. Potential allergens, polyethylene glycol (PEG), polysorbate and tromethamine are excipients. The authors propose allergy evaluation of persons with the following histories: 1-anaphylaxis to injectable drug or vaccine containing PEG or derivatives; 2-anaphylaxis to oral/topical PEG containing products; 3-recurrent anaphylaxis of unknown cause; 4-suspected or confirmed allergy to any mRNA vaccine; and 5-confirmed allergy to PEG or derivatives. We recommend a prick-to-prick skin test with the left-over solution in the suspected vaccine vial to avoid waste. Prick test panel should include PEG 4000 or 3500, PEG 2000 and polysorbate 80. The value of in vitro test is arguable., Conclusions: These recommendations will lead to a better knowledge of the management and mechanisms involved in anaphylaxis to COVID-19 vaccines and enable more people with history of allergy to be vaccinated., (© 2022 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Wheat is one of the most commonly consumed foods and a known elicitor of anaphylaxis in children and adults. Reactions in adults are often cofactor dependent and characterized by a prolonged time between food intake and the onset of symptoms making the diagnosis of wheat anaphylaxis challenging., Objective: To characterize a cohort of patients with the history of wheat anaphylaxis to better understand this atypical phenotype of anaphylaxis., Methods: Data from the European Anaphylaxis Registry from 2007 to 2019 (n = 10,636) including 250 patients (213 adults and 37 children) with a history of anaphylaxis caused by wheat were analyzed., Results: Wheat was the most common food elicitor of anaphylaxis in adults in the registry in Central Europe. Reactions to wheat in adults were frequently associated with exercise as a cofactor (82.8%) and partially delayed (57.5%). Only 36.9% of patients had atopic comorbidities, which was uncommonly low for adult patients allergic to other kinds of foods (63.2%). Anaphylaxis to wheat presented frequently with cardiovascular symptoms (86.7%) including severe symptoms such as loss of consciousness (41%) and less often with respiratory symptoms (53.6%). The reactions to wheat were more severe than reactions to other foods (odds ratio [OR] = 4.33), venom (OR = 1.58), or drugs (OR = 2.11)., Conclusions: Wheat is a relevant elicitor of anaphylaxis in adults in Central Europe. Wheat anaphylaxis is highly dependent on the presence of cofactors and less frequently associated with atopic diseases compared with other food allergies. More data on mechanisms of wheat-induced anaphylaxis are required to develop preventive measures for this potentially life-threatening disease., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Hypersensitivity reactions (HSRs) to nondextran iron products (NDIPs) are rare, but can manifest with severe signs and symptoms. Predisposing risk factors are not well understood., Objective: To characterize patients with HSRs to NDIPs, with a special focus on possible risk factors., Methods: We analyzed clinical characteristics of patients with HSRs to NDIPs referred to our allergy division between 2007 and 2019 compared with tolerant controls, including the type of the eliciting NDIP, severity and characteristics of the HSR, atopy status, history of allergies and urticaria, laboratory and skin test results, and outcome of reexposure with NDIPs., Results: We evaluated the data of 59 patients and 21 controls. Sixteen patients and 4 controls received the NDIP iron sucrose and 41 patients and 15 controls received ferric carboxymaltose. In 2 patients and in 2 controls, the culprit NDIP was not known. Twenty-seven patients (46%) experienced an anaphylactic reaction grade I, 15 (25%) a grade II reaction, and 17 (29%) a grade III reaction according to Ring and Messmer. On analyzing the history, we found that 22 patients (37%) and 3 controls (14%) reported previous HSRs to other medications. Interestingly, more than half the patients (n = 35 [59%]) compared with only 7 controls (33%) reported an episode of any type of urticaria in their previous history. Most patients (n = 15 [79%]) tolerated reexposure of an NDIP using a low-reactogenic administration protocol., Conclusions: A history of drug hypersensitivity and urticaria represent potential risk factors for HSRs to NDIPs. On the basis of our findings, we propose an algorithm for practical management of patients receiving NDIPs aiming to prevent HSRs., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Age is one of the most important factors influencing the course of anaphylaxis: moreover, the frequency of elicitors of anaphylaxis is age-associated. We analyzed 8,465 anaphylactic episodes in adult patients in three age groups with a focus on patients in the middle-age group (35 - 65 years old). Insect venom was the most frequent trigger in this age group (51.2%) followed by drugs (22.8%) and food (17.3%). Severe reactions were observed in 40.1% of middle-aged patients and occurred more frequently in this age group than in patients below 35 years (27.6%) and less frequently than in patients over 65 years (55.6%). The symptoms and comorbidity profile also changed with age, most significantly regarding the increase in rates of concomitant cardiologic diseases and (severe) cardiovascular symptoms., (© Dustri-Verlag Dr. K. Feistle.)

Background: Irritant contact dermatitis (ICD) is caused by the acute locally toxic effect of a strong irritant, or the cumulative exposure to various weaker physical and/or chemical irritants., Objectives: To describe the characteristics of patients with ICD in the population patch tested in the European Surveillance System on Contact Allergies (ESSCA; www.essca-dc.org) database., Methods: Data collected by the ESSCA in consecutively patch-tested patients from January 2009 to December 2018 were analyzed., Results: Of the 68 072 patients, 8702 were diagnosed with ICD (without concomitant allergic contact dermatitis [ACD]). Hand and face were the most reported anatomical sites, and 45.7% of the ICD was occupational ICD (OICD). The highest proportions of OICD were found in metal turners, bakers, pastry cooks, and confectionery makers. Among patients diagnosed with ICD, 45% were found sensitized with no relevance for the current disease., Conclusions: The hands were mainly involved in OICD also in the subgroup of patients with contact dermatitis, in whom relevant contact sensitization had been ruled out, emphasizing the need for limiting irritant exposures. However, in difficult-to-treat contact dermatitis, unrecognized contact allergy, or unrecognized clinical relevance of identified allergies owing to incomplete or wrong product ingredient information must always be considered., (Contact Dermatitis© 2021 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Venom-induced anaphylaxis (VIA) is a common, potentially life-threatening hypersensitivity reaction associated with (1) a specific symptom profile, 2) specific cofactors, and 3) specific management. Identifying the differences in phenotypes of anaphylaxis is crucial for future management guidelines and development of a personalized medicine approach., Objective: This study aimed to evaluate the phenotype and risk factors of VIA., Methods: Using data from the European Anaphylaxis Registry (12,874 cases), we identified 3,612 patients with VIA and analyzed their cases in comparison with sex- and age-matched anaphylaxis cases triggered by other elicitors (non-VIA cases [n = 3,605])., Results: VIA more frequently involved more than 3 organ systems and was associated with cardiovascular symptoms. The absence of skin symptoms during anaphylaxis was correlated with baseline serum tryptase level and was associated with an increased risk of a severe reaction. Intramuscular or intravenous epinephrine was administered significantly less often in VIA, in particular, in patients without a history of anaphylaxis. A baseline serum tryptase level within the upper normal range (8-11.5 ng/mL) was more frequently associated with severe anaphylaxis., Conclusion: Using a large cohort of VIA cases, we have validated that patients with intermediate baseline serum tryptase levels (8-11 ng/mL) and without skin involvement have a higher risk of severe VIA. Patients receiving β-blockers or angiotensin-converting enzyme inhibitors had a higher risk of developing severe cardiovascular symptoms (including cardiac arrest) in VIA and non-VIA cases. Patients experiencing VIA received epinephrine less frequently than did cases with non-VIA., (Copyright © 2020 American Academy of Allergy, Asthma & Immunology. All rights reserved.)

Background: Anaphylaxis is an immediate hypersensitivity reaction. However, a biphasic course with the second onset of symptoms can occur hours after the initial phase. Little is known about the causes of biphasic anaphylaxis making the identification of patients at risk difficult., Objective: To identify factors predisposing for biphasic anaphylaxis for the better understanding of these reactions., Methods: Data from the Anaphylaxis Registry (from 11 countries) including 8736 patients with monophasic and 435 biphasic anaphylaxis were analyzed., Results: The rate of biphasic reactions in this large cohort was 4.7%. The identified risk factors were reaction severity (grade III/IV vs grade II: odds ratio [OR] = 1.34; 95% confidence interval [CI]: 1.1-1.62); multiorgan involvement; skin, gastrointestinal, severe respiratory, and cardiac symptoms; anaphylaxis caused by peanut/tree nut (OR = 1.78; 95% CI: 1.38-2.23) or an unknown elicitor (OR = 1.96; 95% CI: 1.41-2.72); exercise as a cofactor (OR = 1.44; 95% CI: 1.17-1.78); chronic urticaria as a comorbidity (OR = 2.12; 95% CI: 1.19-3.78); a prolonged interval between the contact with the elicitor and start of primary symptoms (OR for >30 vs <30 min: 1.38; 95% CI: 1.08-1.76); and antihistamine treatment (OR = 1.52; 95% CI: 1.14-2.02)., Conclusion: A biphasic course of anaphylaxis occurs more frequently in severely affected patients with multiorgan involvement. However, we identified multiple additional predictors, suggesting that the pathogenesis of biphasic reactions is more complex than being a rebound of a severe primary reaction., (Copyright © 2020 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Humans are exposed to a variety of metals on a daily basis, and nickel is the most frequent contact allergen. Little is known about the frequency of sensitization to indium and iridium., Objectives: Study the prevalence of indium and iridium sensitization and evaluate the optimal patch test conditions., Methods: A total of 364 patients were patch tested at the allergy unit of the University Hospital of Basel. Pure metals, metal chlorides, and metal sulfates were applied in petrolatum or water in Inert Quadrate (IQ) test chambers for 2 days and read twice at day (D) 2, and between D4 and D7., Results: Eleven patients reacted to indium salts (3.0%), 13 to iridium salts (3.6%), and one reacted to both salts. None of the patients reacted to pure metals. Nineteen of the 23 patients who reacted either to indium or iridium showed concomitant positive reactions to other metals, mainly nickel and palladium., Conclusion: This retrospective clinical study provides insight into the prevalence and test conditions of two rarely tested metal allergens in a large patient cohort. A considerable number of indium- or iridium-positive subjects had co-sensitization to other metals., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Patients with a history of anaphylaxis are at risk of future anaphylactic reactions. Thus, secondary prevention measures are recommended for these patients to prevent or attenuate the next reaction., Methods: Data from the Anaphylaxis Registry were analyzed to identify secondary prevention measures offered to patients who experienced anaphylaxis. Our analysis included 7788 cases from 10 European countries and Brazil., Results: The secondary prevention measures offered varied across the elicitors. A remarkable discrepancy was observed between prevention measures offered in specialized allergy centers (84% of patients were prescribed adrenaline autoinjectors following EAACI guidelines) and outside the centers: Here, EAACI guideline adherence was only 37%. In the multivariate analysis, the elicitor of the reaction, age of the patient, mastocytosis as comorbidity, severity of the reaction, and reimbursement/availability of the autoinjector influence physician's decision to prescribe one., Conclusions: Based on the low implementation of guidelines concerning secondary prevention measures outside of specialized allergy centers, our findings highlight the importance of these specialized centers and the requirement of better education for primary healthcare and emergency physicians., (© 2019 The Authors. Allergy published by John Wiley & Sons Ltd.)

Refractory anaphylaxis (unresponsive to treatment with at least two doses of minimum 300 μg adrenaline) is a rare and often fatal hypersensitivity reaction. Comprehensive data on its definition, prevalence, and risk factors are missing. Using the data from the European Anaphylaxis Registry (11,596 cases in total) we identified refractory anaphylaxis cases ( n = 42) and analyzed these in comparison to a control group of severe anaphylaxis cases ( n = 4,820). The data show that drugs more frequently elicited refractory anaphylaxis (50% of cases, p < 0.0001) compared to other severe anaphylaxis cases (19.7%). Cases elicited by insects ( n = 8) were more often due to bees than wasps in refractory cases (62.5 vs. 19.4%, p = 0.009). The refractory cases occurred mostly in a perioperative setting (45.2 vs. 9.05, p < 0.0001). Intramuscular adrenaline (as a first line therapy) was administered in 16.7% of refractory cases, whereas in 83.3% of cases it was applied intravenously (significantly more often than in severe anaphylaxis cases: 12.3%, p < 0.0001). Second line treatment options (e.g., vasopression with dopamine, methylene blue, glucagon) were not used at all for the treatment of refractory cases. The mortality rate in refractory anaphylaxis was significantly higher (26.2%) than in severe cases (0.353%, p < 0.0001). Refractory anaphylaxis is associated with drug-induced anaphylaxis in particular if allergens are given intravenously. Although physicians frequently use adrenaline in cases of perioperative anaphylaxis, not all patients are responding to treatment. Whether a delay in recognition of anaphylaxis is responsible for the refractory case or whether these cases are due to an overflow with mast cell activating substances-requires further studies. Reasons for the low use of second-line medication (i.e., methylene blue or dopamine) in refractory cases are unknown, but their use might improve the outcome of severe refractory anaphylaxis cases., (Copyright © 2019 Francuzik, Dölle-Bierke, Knop, Scherer Hofmeier, Cichocka-Jarosz, García, Lang, Maris, Renaudin and Worm.)

Allergies to non-betalactam antibiotics: a challenge in practice Abstract. The heterogeneous group of non-betalactam antibiotics can in part trigger very severe immunologically mediated hypersensitivity reactions. The risks are very differently distributed among the different representatives and a genetic predisposition to the development of Stevens-Johnson syndrome / toxic epidermal necrolysis or Drug rash with eosinophilia and systemic symptoms (DRESS syndrome) can be observed. Individual patient groups are particularly frequently affected, including patients with HIV or cystic fibrosis. In this overview, the individual drug groups and corresponding risk situations as well as the available diagnostic means are discussed.

Background: Hypersensitivity to metals as a cause of implant-related complications has been a subject of controversy. Projections indicate an increase in the frequency of joint replacements of between 300% and 600% by the year 2030; therefore, this issue is of considerable interest., Objective: To evaluate sensitization to implant materials in patients with implant-related complications, to identify allergens, and to clarify whether hypersensitivity is a relevant cause., Methods: Patients with implant-related complications or a positive history of contact allergy and planned total joint replacements referred for allergological investigation between 2004 and 2017 were retrospectively analysed., Results: In total, 311 patients were included. A positive patch test reaction to a metal was seen in 64.4% of preoperative patients and in 54.6% of patients with implant-related complications. Common alloy metals such as cobalt, chromium and titanium gave positive reactions in up to 2.9% of patients with implant-related complications. None of the patients with skin changes had a positive patch test reaction to an implant metal., Conclusion: Other factors, such as the type of replaced joint and mechanical stress, seem to be more relevant for implant-related complications. Sensitization to metals or other materials seems to rarely play a role, and is overestimated., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The patch test is the standard procedure for diagnosing delayed-type sensitization. If a patch test is not possible, the flow cytometric lymphocyte proliferation test (LPT), which determines the number and type of cells responding to a specific antigen in vitro, might be considered as an alternative., Objectives: Our aim was to establish a flow cytometric LPT for the detection of delayed-type allergic responses to cobalt, and to determine the correlation between stimulation indices (SIs) in LPT and the grade of patch test reactions. With the patch test as a diagnostic reference, we also assessed the sensitivity and specificity of the LPT., Methods: Fifty-four patients patch tested with the baseline series including cobalt (CoCl 2 ) were additionally tested with the flow cytometric LPT with CoCl 2 ., Results: There was a significant correlation between the results of both tests: r s  = 0.43; P = .001. The LPT with CoCl 2 showed a sensitivity of 52.6% and a specificity of 85.7%. Corresponding to the low sensitivity of the LPT, high likelihood ratios for a positive patch test reaction were reached only in cases of strong lymphocyte proliferation (SI ≥ 10)., Conclusions: In cases of clearly increased SIs, the flow cytometric LPT with CoCl 2 gives relevant diagnostic information, and represents a valuable alternative to patch testing., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Temporary tattoos made with an extract of the jagua fruit (Genipa americana L.) are becoming increasingly popular. It is claimed that it is 'dermatologically tested' and does not contain p-phenylenediamine. Extracts of jagua and gardenia fruits have been used by indigenous people in South America, as well as in traditional Chinese medicine, for centuries. Genipin is currently used for its cross-linking effect in the manufacture of polysaccharides, and is being investigated for its anti-inflammatory and other properties., Objectives: To report the presence of the allergenic substance genipin in a self-administered temporary tattoo dye made from the fruit juice of jagua (Genipa americana L.)., Patients and Methods: A 39-year-old female who repeatedly applied 'completely natural and 100% safe' Earth Jagua® tattoo, obtained via the internet, to her left hand developed allergic contact dermatitis within 6 weeks. Analysis of the dye showed the presence of geniposide and genipin., Results: Patch tests with the dye and with its main components, including genipin, gave strong positive reactions to the latter. There was no sensitization to other ingredients or p-amino compounds., Conclusions: We report an extensively evaluated case of allergic contact dermatitis caused by a temporary Earth Jagua® tattoo. The allergen identified is genipin, a substance that is increasingly used for tattoos and as a therapeutic agent in medicine. This could result in an increase in the number of allergic reactions in the future., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

In theory, all medicines can elicit allergic reactions. However, there are large differences in the frequency and clinical presentation of these reactions. Antibiotics, antiepileptic agents and NSADs trigger allergic reactions most frequently. The risk of drug allergy and of a complicated clinical course depends on the individual degree of immune activation, the dose, duration of treatment, route of administration, patient sex as well as HLA-traits, which are increasingly being identified. This article presents the commonest types of immune-mediated drug-related hypersensitivity reactions and discusses red flags which are associated with a complicated clinical course.

Of the two most common obstructive lung diseases - bronchial asthma and chronic obstructive pulmonary disease (COPD) - asthma is clearly associated with a possible allergic background, therefore an allergological examination should be included in the work-up of this disease. COPD on the other hand is usually not expected to be linked with an atopic diathesis. Medical history, clinical manifestations, the presence of other atopic diseases, prick tests and measurement of specific IgE antibodies in the serum provide an indication of an allergic genesis of the obstructive pulmonary disease. Bronchial asthma can be roughly divided into an allergic phenotype (TH2-weighted) and a non-allergic phenotype (non-TH2-weighted). The TH2- weighted form leads to an infiltration of eosinophils into the bronchial wall allowing the possibility of a higher concentration of nitrogen oxide in the exhaled air (FeNO measurement) to be detected. In addition to the differentiation between allergic and non-allergic bronchial obstruction, an evaluation of symptoms associated with the workplace (work related asthma) must take place. Furthermore, questions about an intolerance to aspirin (aspirin - exacerbated respiratory disease) or exercise induced symptoms (exercise-induced asthma) should be asked. After a careful interpretation of clinical symptoms and findings in allergy tests, an allergologist can analyze the usefulness of a specific immunotherapy (SIT). For children who suffer from allergic rhinoconjunctivitis, an early SIT can prevent the shift to inflammation of the lower respiratory tract (asthma). Due to the overlapping pathophysiology and symptomatology between bronchial asthma and chronic obstructive pulmonary disease an allergological examination should be considered also in COPD patients.

Drug hypersensitivity reactions can occur with many drugs, are unpredictable, may affect any organ system and range widely in clinical severity from mild pruritus to exanthems to anaphylaxis. In most cases, the suspected drug must be avoided in the future. However, for certain patients, the particular drug may be essential for an optimal therapy. Under these circumstances, desensitization may be performed.

Allergic rhinoconjunctivits and asthma are frequent diseases. About one in ten asthma cases is caused by an occupational hazard, either by an allergic or a non-immunologic mechanism. Primary or secondary preventive measures should be able to prevent these cases. Often, occupational rhinitis precedes the development of occupational asthma. Important causative agents are flours, plant and enzyme powders, laboratory animals, latex, isocyanates and hardeners, epoxy resins, acrylates, formaldehyde and welding fumes. Early diagnosis and the installation of protective measures are decisive for the prognosis of occupational respiratory disease.

Drugs may elicit a considerable variety of clinical signs, often affecting the skin and the mucous membranes. The most common are maculopapular exanthema, urticaria and angioedema. More rarely pustular, vesiculobullous, vasculitic and lichenoid lesions may be observed. Apart from the morphology, also the chronology of the occurrence and the evolution of the single skin lesions and the exanthema are paramount in the clinical diagnosis. Often, the skin is the only affected organ; however, it may herald a systemic involvement of internal organs, such as in severe drug-induced hypersensitivity syndromes or anaphylaxis. Cutaneous manifestations, particularly maculopapular exanthemas have a high incidence among patients treated with hematopoietic stem cell transplantation. In many cases, a virus- or drug-induced origin or a combination of both is responsible. However, the transplantation itself may also induce similar skin changes. These exanthemas include most often graft-versus-host disease, and rarely engraftment syndrome or eruption of lymphocyte recovery. The elucidation of the underlying cause of the exanthemas occurring in immune compromised patients and the determination of the correct diagnosis remain challenging. An extensive differential diagnosis has to be put forward. This includes several groups of disorders with sometimes very similar cutaneous manifestations. Manifestations form the underlying disease, complications from therapy, infections and drug reactions are the most common differential diagnoses., (Copyright © 2012 S. Karger AG, Basel.)