RÉSUMÉ
Idiopathic anaphylaxis (IA) remains a frustrating challenge for both patients and physicians. The aim of this paper is to focus on IA in pediatric ages and suggest possible diagnostic algorithms according to specific age ranges (infants, children, and adolescents). In fact, in a variable percentage of patients, despite extensive diagnostic tests, the cause of anaphylactic episodes cannot be identified. Moreover, the lack of a unanimous IA definition requires a careful and detailed diagnostic workup. Prompt recognition of signs and symptoms, especially in younger children, and an accurate clinical history often allow a choice of the most appropriate diagnostic tests and a correct differential diagnosis.
Sujet(s)
Anaphylaxie , Humains , Anaphylaxie/diagnostic , Anaphylaxie/thérapie , Anaphylaxie/étiologie , Anaphylaxie/traitement médicamenteux , Enfant , Adolescent , Nourrisson , Diagnostic différentiel , Enfant d'âge préscolaire , AlgorithmesRÉSUMÉ
BACKGROUND: Allergic rhinitis (AR) has a substantial socioeconomic impact associated with impaired work productivity. OBJECTIVE: To study the impact of AR on work productivity and estimate the corresponding indirect costs for 40 countries. METHODS: We conducted a cross-sectional study using direct patient data from the MASK-air® app on users with self-reported AR. We used the Work Productivity and Activity Impairment Questionnaire: Allergy Specific to measure the impact of AR on work productivity (presenteeism and absenteeism). Weekly indirect costs were estimated per country, for each level of rhinitis control and considering patients with and without asthma. RESULTS: We assessed data from 677 weeks (364 patients), 280 of which were reported by patients with asthma. Regarding presenteeism, the median impact of AR in weeks of poor disease control was 60.7% (P25-P75=24.9-74.2%), while partial and good disease control were respectively associated with an impact of 25.0% (P25-P75=12.1-42.4%) and 4.4% (P25-75=0.8-12.9%). In poorly-controlled weeks, presenteeism was associated with indirect costs ranging from 65.7 US Dollars purchase power parity (US$ PPPs) (P25-P75=29.2-143.2) in Brazil to 693.6 US$ PPP (P25-P75=405.2-1094.9) in Iceland. Median absenteeism per week was of 0% for all levels of rhinitis control. Patients with AR+asthma showed higher overall work impairment than patients with AR alone, particularly in poorly-controlled weeks (median work impairment in AR alone=39.1% [P25-P75=12.5-71.9%]; median work impairment in AR+asthma=68.4% [P25-P75=54.6-80.2%]). CONCLUSION: Poor AR control was associated with decreased work productivity and increased indirect costs, particularly in patients with AR+asthma. The estimates from this study underpin the economic burden of AR.
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Breastfeeding is the most important nutrition source for infants. However, managing breastfed infants with signs and symptoms related to food allergy can be difficult. Many studies have shown the presence of different food allergens in breast milk, but the clinical role of these antigens in human milk is still much debated. Milk is the main suspect in exclusively breastfed infants with signs and symptoms attributable to food allergy, even if other foods may be responsible. This narrative review analyzes the recommendations provided by international guidelines to determine the diagnosis and management of IgE-mediated and non-IgE-mediated food allergies in exclusively breastfed infants. Dietary restrictions in lactating mothers of infants with suspected FA are usually not necessary. Only in the very few cases where significant allergy signs and symptoms occur in the infant during exclusive breastfeeding should the lactating mother follow an elimination diet for the suspected food for a short period.
Sujet(s)
Allaitement naturel , Hypersensibilité alimentaire , Lactation , Lait humain , Humains , Hypersensibilité alimentaire/diagnostic , Hypersensibilité alimentaire/diétothérapie , Nourrisson , Femelle , Lait humain/immunologie , Régime alimentaire , Nouveau-né , Mères , Régimes d'évictionRÉSUMÉ
The traditional healthcare model is focused on diseases (medicine and natural science) and does not acknowledge patients' resources and abilities to be experts in their own life based on their lived experiences. Improving healthcare safety, quality and coordination, as well as quality of life, are important aims in the care of patients with chronic conditions. Person-centred care needs to ensure that people's values and preferences guide clinical decisions. This paper reviews current knowledge to develop (i) digital care pathways for rhinitis and asthma multimorbidity and (ii) digitally-enabled person-centred care (1). It combines all relevant research evidence, including the so-called real-world evidence, with the ultimate goal to develop digitally-enabled, patient-centred care. The paper includes (i) Allergic Rhinitis and its Impact on Asthma (ARIA), a two-decade journey, (ii) Grading of Recommendations, Assessment, Development and Evaluation (GRADE), the evidence-based model of guidelines in airway diseases, (iii) mHealth impact on airway diseases, (iv) from guidelines to digital care pathways, (v) embedding Planetary Health, (vi) novel classification of rhinitis and asthma, (vi) embedding real-life data with population-based studies, (vii) the ARIA-EAACI strategy for the management of airway diseases using digital biomarkers, (viii) Artificial Intelligence, (ix) the development of digitally-enabled ARIA Person-Centred Care and (x) the political agenda. The ultimate goal is to propose ARIA 2024 guidelines centred around the patient in order to make them more applicable and sustainable.
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Background: Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy characterized by gastrointestinal symptom onset within 1-4 hours from trigger food ingestion. In the literature, some authors have previously described the possibility that a patient with FPIES may develop an IgE-mediated allergy to the same trigger food, especially cow's milk (CM). Case Presentation: We reported five cases of CM-FPIES converting to IgE-mediated CM allergy presented at our tertiary pediatric Allergy Unit and performed a review of the literature, aiming to characterize the clinical features of patients who are at risk of developing such conversion. Conclusions: This phenomenon raises the question of whether IgE-mediated and non-IgE-mediated allergies represent a spectrum of the same disease and highlights the need for further investigation to understand the pathophysiological mechanisms of this process.
Sujet(s)
Entérocolite , Immunoglobuline E , Hypersensibilité au lait , Humains , Entérocolite/immunologie , Entérocolite/étiologie , Entérocolite/diagnostic , Hypersensibilité au lait/immunologie , Hypersensibilité au lait/diagnostic , Immunoglobuline E/immunologie , Immunoglobuline E/sang , Femelle , Nourrisson , Mâle , Animaux , Protéines de lait/effets indésirables , Protéines de lait/immunologie , Syndrome , Enfant d'âge préscolaire , Bovins , Lait/effets indésirables , Lait/immunologie , Hypersensibilité alimentaire/immunologie , Hypersensibilité alimentaire/étiologie , Hypersensibilité alimentaire/diagnosticSujet(s)
Réactions croisées , Hypersensibilité alimentaire , Graines , Sesamum , Humains , Sesamum/immunologie , Sesamum/effets indésirables , Enfant , Femelle , Hypersensibilité alimentaire/immunologie , Mâle , Réactions croisées/immunologie , Enfant d'âge préscolaire , Immunoglobuline E/immunologie , Allergènes/immunologie , AdolescentRÉSUMÉ
The recognition of constipation as a possible non-Immunoglobulin E (IgE)-mediated allergic condition is challenging because functional constipation (unrelated to food allergies) is a common health problem with a reported worldwide prevalence rate of up to 32.2% in children. However, many studies in children report challenge proven cow's milk allergy and constipation as a primary symptom and have found that between 28% and 78% of children improve on a cow's milk elimination diet. Due to the paucity of data and a focus on IgE-mediated allergy, not all food allergy guidelines list constipation as a symptom of food allergy. Yet, it is included in all cow's milk allergy guidelines available in English language. The Exploring Non-IgE-Mediated Allergy (ENIGMA) Task Force (TF) of the European Academy for Allergy and Clinical Immunology (EAACI) considers in this paper constipation in the context of failure of standard treatment and discuss the role of food allergens as culprit in constipation in children. This position paper used the Delphi approach in reaching consensus on both diagnosis and management, as currently published data are insufficient to support a systematic review.
Sujet(s)
Constipation , Hypersensibilité alimentaire , Humains , Constipation/diagnostic , Constipation/thérapie , Constipation/étiologie , Enfant , Hypersensibilité alimentaire/diagnostic , Hypersensibilité alimentaire/complications , Hypersensibilité alimentaire/thérapie , Enfant d'âge préscolaire , Hypersensibilité au lait/diagnostic , Hypersensibilité au lait/thérapie , Hypersensibilité au lait/complications , Hypersensibilité au lait/immunologie , Immunoglobuline E/sang , Immunoglobuline E/immunologie , Méthode Delphi , Guides de bonnes pratiques cliniques comme sujet , Nourrisson , Allergènes/immunologie , Animaux , PrévalenceRÉSUMÉ
To inform the clinical practice guidelines' recommendations developed by the European Academy of Allergy and Clinical Immunology systematic reviews (SR) assessed using GRADE on the impact of environmental tobacco smoke (ETS) and active smoking on the risk of new-onset asthma/recurrent wheezing (RW)/low lung function (LF), and on asthma-related outcomes. Only longitudinal studies were included, almost all on combustion cigarettes, only one assessing e-cigarettes and LF. According to the first SR (67 studies), prenatal ETS increases the risk of RW (moderate certainty evidence) and may increase the risk of new-onset asthma and of low LF (low certainty evidence). Postnatal ETS increases the risk of new-onset asthma and of RW (moderate certainty evidence) and may impact LF (low certainty evidence). Combined in utero and postnatal ETS may increase the risk of new-onset asthma (low certainty evidence) and increases the risk of RW (moderate certainty evidence). According to the second SR (24 studies), ETS increases the risk of severe asthma exacerbations and impairs asthma control and LF (moderate certainty evidence). According to the third SR (25 studies), active smoking increases the risk of severe asthma exacerbations and of suboptimal asthma control (moderate certainty evidence) and may impact asthma-related quality-of-life and LF (low certainty evidence).
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Peanut allergy affects about 1%-3% of the pediatric population in the world, with an important increase in the last decades. Nowadays, international guidelines recommend the early introduction of peanuts in the infant diet, with poor information about the quantity and the frequency of the intake. Allergen immunotherapy may represent the only therapeutic strategy able to modify the natural history of peanut allergy. In particular, oral immunotherapy showed the most promising results in terms of efficacy, but with significant rates of adverse reactions, mostly gastrointestinal. In 2020, the Food and Drug Administration and the European Medicines Agency approved Palforzia®, an oral drug for patients aged 4-17 years. Several studies are ongoing to improve the tolerability of oral immunotherapy and standardize the desensitization protocols. Sublingual immunotherapy permits to offer much lower doses than oral immunotherapy, but fewer adverse events are shown. Subcutaneous immunotherapy is associated with the greatest systemic adverse effects. Epicutaneous immunotherapy, for which Viaskin® patch was approved, has the highest safety profile. Innovative studies are evaluating the use of biological drugs, such as omalizumab or dupilumab, and probiotics, such as Lactobacillus rhamnosus, in monotherapy or associated with oral immunotherapy. Therapy for peanut allergy is constantly evolving, and new perspectives are ongoing to develop.
Sujet(s)
Allergènes , Désensibilisation immunologique , Hypersensibilité aux arachides , Humains , Hypersensibilité aux arachides/thérapie , Hypersensibilité aux arachides/immunologie , Désensibilisation immunologique/méthodes , Enfant , Enfant d'âge préscolaire , Adolescent , Allergènes/immunologie , Allergènes/administration et posologie , Administration par voie orale , Arachis/immunologie , Probiotiques/usage thérapeutique , Probiotiques/administration et posologieRÉSUMÉ
Trichothiodystrophy (TTD) is a rare congenital disorder caused by genetic mutations, leading to hair and skin abnormalities. We report successful treatment of a TTD case using dupilumab, a monoclonal antibody targeting IL-4Rα. The patient, a 7-year-old boy, exhibited significant improvement in skin and hair conditions, suggesting the potential of dupilumab as a therapeutic option for TTD. Further research is needed to elucidate its mechanism and efficacy in TTD treatment.
RÉSUMÉ
BACKGROUND: IgE-mediated food allergy (FA) is a global health concern with substantial individual and societal implications. While diverse intervention strategies have been researched, inconsistencies in reported outcomes limit evaluations of FA treatments. To streamline evaluations and promote consistent reporting, the Core Outcome Measures for Food Allergy (COMFA) initiative aimed to establish a Core Outcome Set (COS) for FA clinical trials and observational studies of interventions. METHODS: The project involved a review of published clinical trials, trial protocols and qualitative literature. Outcomes found as a result of review were categorized and classified, informing a two-round online-modified Delphi process followed by hybrid consensus meeting to finalize the COS. RESULTS: The literature review, taxonomy mapping and iterative discussions with diverse COMFA group yielded an initial list of 39 outcomes. The iterative online and in-person meetings reduced the list to 13 outcomes for voting in the formal Delphi process. One more outcome was added based on participant suggestions after the first Delphi round. A total of 778 participants from 52 countries participated, with 442 participating in both Delphi rounds. No outcome met a priori criteria for inclusion, and one was excluded as a result of the Delphi. Thirteen outcomes were brought to the hybrid consensus meeting as a result of Delphi and two outcomes, 'allergic symptoms' and 'quality of life' achieved consensus for inclusion as 'core' outcomes. CONCLUSION: In addition to the mandatory reporting of adverse events for FA clinical trials or observational studies of interventions, allergic symptoms and quality of life should be measured as core outcomes. Future work by COMFA will define how best to measure these core outcomes.
Sujet(s)
Hypersensibilité alimentaire , Qualité de vie , Humains , Méthode Delphi , Hypersensibilité alimentaire/diagnostic , Hypersensibilité alimentaire/thérapie , Immunoglobuline E , , Plan de recherche , Résultat thérapeutique , Essais cliniques comme sujet , Études observationnelles comme sujetRÉSUMÉ
Asthma is one of the most common non-communicable diseases, and its prevalence and morbidity are influenced by a wide array of factors that are only partially understood. In addition to individual predisposition linked to genetic background and early life infections, environmental factors are crucial in determining the impact of asthma both on an individual patient and on a population level.Several studies have examined the role of the environment where asthmatic subjects live in the pathogenesis of asthma. This review aims to investigate the differences in the prevalence and characteristics of asthma between the pediatric population residing at higher altitudes and children living at lower altitudes, trying to define factors that potentially determine such differences. For this purpose, we reviewed articles from the literature concerning observational studies assessing the prevalence of pediatric asthma in these populations and its characteristics, such as spirometric and laboratory parameters and associated sensitization to aeroallergens.Despite the heterogeneity of the environments examined, the hypothesis of a beneficial effect of residing at a higher altitude on the prevalence of pediatric asthma could be confirmed, as well as a good profile on airway inflammation in asthmatic children. However, the possibility of a higher hospitalization risk for asthma in children living at higher altitudes was demonstrated. Moreover, a positive association between residing at a higher altitude and sensitization to pollens and between lower altitude and sensitization to house dust mites could be confirmed in some pediatric patients, even if the results are not homogeneous, probably due to the different geographical and climatic regions considered. Nonetheless, further studies, e.g., extensive and international works, need to be conducted to better understand the complex interplay between different environmental factors, such as altitude, and the pathogenesis of asthma and how its prevalence and characteristics could vary due to climate change.
Sujet(s)
Altitude , Asthme , Humains , Enfant , Asthme/épidémiologie , Asthme/étiologie , Génotype , Géographie , HospitalisationRÉSUMÉ
Imported allergens are involved in many allergic reactions, with unexpected and unusual implications. They can be involved in developing asthma, allergic rhinoconjunctivitis, Hymenoptera venom allergies and food allergies. Imported allergens can be implied in respiratory allergies attributable to commercial practices and accidental diffusion through air currents that have introduced non-native species in new geographical contexts. Ambrosia artemisiifolia L., a plant native to North America and currently in the western part of Lombardy, represents an example. Moreover, a variation in the pollen concentration in the Northwest Tuscany area and Trentino Alto-Adige was observed. Cannabis sativa is another imported allergen used frequently by adolescents. Regarding potential imported food allergens, there is no validated list. Imported food allergens derive from ethnic foods, referring to Mexican/Latin American, Chinese/Japanese, Southeast Asian, Arab/Middle Eastern and African cuisine. Four insect flours were recently introduced to the European and Italian markets (Acheta domesticus, Alphitobius diaperinus, Tenebrio molitor and Locusta migratoria). The association between the accidental introduction through commercial traffic, climate change, and the absence of natural enemies in the destination ecosystem is related to the introduction of a specific Hymenoptera, Vespa velutina, in Italy and Europe. External events attributable to human activities, such as climate change and the introduction of non-native plants, foods and Hymenoptera through trade, have contributed to the issue of imported allergens. Making the correct diagnosis and guiding the diagnostic and therapeutic path in this particular context represent the concerns of the pediatric allergist.
Sujet(s)
Allergènes , Hypersensibilité , Adolescent , Humains , Enfant , Écosystème , Italie/épidémiologie , EuropeRÉSUMÉ
Anaphylaxis is a life-threatening reaction characterized by the acute onset of symptoms involving different organ systems and requiring immediate medical intervention. The incidence of fatal food anaphylaxis is 0.03 to 0.3 million/people/year. Most fatal food-induced anaphylaxis occurs in the second and third decades of life. The identified risk factors include the delayed use of epinephrine, the presence of asthma, the use of recreational drugs (alcohol, nicotine, cannabis, etc.), and an upright position. In the United Kingdom (UK) and Canada, the reported leading causal foods are peanuts and tree nuts. In Italy, milk seems to be the most common cause of fatal anaphylaxis in children < 18 years. Fatal food anaphylaxis in Italian children and adolescents almost always occurs outside and is characterized by cardiorespiratory arrest; auto-injectable adrenaline intramuscular was available in few cases. Mortality from food anaphylaxis, especially in children, is a very rare event with stable incidence, but its risk deeply impacts the quality of life of patients with food allergy and their families. Prevention of fatal food anaphylaxis must involve patients and their families, as well as the general public, public authorities, and patients' associations.
Sujet(s)
Anaphylaxie , Asthme , Adolescent , Adulte , Enfant , Humains , Anaphylaxie/diagnostic , Anaphylaxie/épidémiologie , Anaphylaxie/étiologie , Qualité de vie , Épinéphrine/usage thérapeutique , ArachisRÉSUMÉ
BACKGROUND: In case of suspected hypersensitivity reactions (HRs) to drugs, a challenging area for pediatricians is detecting relevant elements in the parent-reported history, in order to reach a definite diagnosis. We analyzed the concordance between the description of the HR and the medical reports documented at the time of the event. Furthermore, we studied any correlation between clinical history variables and the prediction of true allergy. METHODS: We retrospectively collected 50 charts of children referred to our Allergy Unit, after a previous access to the Emergency Department. We compared the description of the HR at acute phase to the history told by parents. Type and timing of the HR and culprit drug were classified as "known" or "unknown." The diagnosis was confirmed or excluded at the end of the investigations. Logistic regression analysis was performed to find any significant association. RESULTS: The type of the HR was known in 74%, the timing in 28%, and the culprit drug in 98%. We showed that having had a severe HR had an increased odds of remembering the timing; being older >6 years and having had an immediate HR had an increased odds of remembering the type; time to diagnostic was lower in patients whose parents remembered the type of HR. CONCLUSION: Our paper underlines the importance of an accurate anamnesis at the time of the event. Providing the physicians with a standardized Case Report Form could be a useful tool to simplify the diagnostic work-up and minimize mistakes due to lack of memory.
Sujet(s)
Hypersensibilité médicamenteuse , Hypersensibilité , Enfant , Humains , Études rétrospectives , Hypersensibilité médicamenteuse/diagnostic , Service hospitalier d'urgences , ParentsRÉSUMÉ
Exercise-induced bronchoconstriction (EIB) is characterized by the narrowing of airways during or after physical activity, leading to symptoms such as wheezing, coughing, and shortness of breath. Distinguishing between EIB and exercise-induced asthma (EIA) is essential, given their divergent therapeutic and prognostic considerations. EIB has been increasingly recognized as a significant concern in pediatric athletes. Moreover, studies indicate a noteworthy prevalence of EIB in children with atopic predispositions, unveiling a potential link between allergic sensitivities and exercise-induced respiratory symptoms, underpinned by an inflammatory reaction caused by mechanical, environmental, and genetic factors. Holistic management of EIB in children necessitates a correct diagnosis and a combination of pharmacological and non-pharmacological interventions. This review delves into the latest evidence concerning EIB in the pediatric population, exploring its associations with atopy and sports, and emphasizing the appropriate diagnostic and therapeutic approaches by highlighting various clinical scenarios.
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Asthme à l'effort , Hypersensibilité immédiate , Hypersensibilité , Sports , Humains , Enfant , Bronchoconstriction , Asthme à l'effort/diagnostic , Asthme à l'effort/traitement médicamenteux , Asthme à l'effort/épidémiologie , Exercice physiqueRÉSUMÉ
Air pollution is one of the biggest environmental threats for asthma. Its impact is augmented by climate change. To inform the recommendations of the EAACI Guidelines on the environmental science for allergic diseases and asthma, a systematic review (SR) evaluated the impact on asthma-related outcomes of short-term exposure to outdoor air pollutants (PM2.5, PM10, NO2, SO2, O3, and CO), heavy traffic, outdoor pesticides, and extreme temperatures. Additionally, the SR evaluated the impact of the efficacy of interventions reducing outdoor pollutants. The risk of bias was assessed using ROBINS-E tools and the certainty of the evidence by using GRADE. Short-term exposure to PM2.5, PM10, and NO2 probably increases the risk of asthma-related hospital admissions (HA) and emergency department (ED) visits (moderate certainty evidence). Exposure to heavy traffic may increase HA and deteriorate asthma control (low certainty evidence). Interventions reducing outdoor pollutants may reduce asthma exacerbations (low to very low certainty evidence). Exposure to fumigants may increase the risk of new-onset asthma in agricultural workers, while exposure to 1,3-dichloropropene may increase the risk of asthma-related ED visits (low certainty evidence). Heatwaves and cold spells may increase the risk of asthma-related ED visits and HA and asthma mortality (low certainty evidence).
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Pollution de l'air , Asthme , Exposition environnementale , Humains , Asthme/étiologie , Asthme/prévention et contrôle , Asthme/épidémiologie , Pollution de l'air/effets indésirables , Exposition environnementale/effets indésirables , Polluants atmosphériques/effets indésirables , Hypersensibilité/étiologie , Hypersensibilité/épidémiologie , Hypersensibilité/prévention et contrôleRÉSUMÉ
Systematic review using GRADE of the impact of exposure to volatile organic compounds (VOCs), cleaning agents, mould/damp, pesticides on the risk of (i) new-onset asthma (incidence) and (ii) adverse asthma-related outcomes (impact). MEDLINE, EMBASE and Web of Science were searched for indoor pollutant exposure studies reporting on new-onset asthma and critical and important asthma-related outcomes. Ninety four studies were included: 11 for VOCs (7 for incidenceand 4 for impact), 25 for cleaning agents (7 for incidenceand 8 for impact), 48 for damp/mould (26 for incidence and 22 for impact) and 10 for pesticides (8 for incidence and 2 for impact). Exposure to damp/mould increases the risk of new-onset wheeze (moderate certainty evidence). Exposure to cleaning agents may be associated with a higher risk of new-onset asthma and with asthma severity (low level of certainty). Exposure to pesticides and VOCs may increase the risk of new-onset asthma (very low certainty evidence). The impact on asthma-related outcomes of all major indoor pollutants is uncertain. As the level of certainty is low or very low for most of the available evidence on the impact of indoor pollutants on asthma-related outcomes more rigorous research in the field is warranted.
Sujet(s)
Pollution de l'air intérieur , Asthme , Composés organiques volatils , Humains , Asthme/étiologie , Asthme/épidémiologie , Pollution de l'air intérieur/effets indésirables , Composés organiques volatils/effets indésirables , Exposition environnementale/effets indésirables , Hypersensibilité/étiologie , Hypersensibilité/épidémiologie , Incidence , Pesticides/effets indésirablesRÉSUMÉ
The majority of viral rashes occurring during an antibiotic therapy are considered as a drug hypersensitivity reaction (DHR). Differentiating a viral rash versus a DHR is difficult or even impossible. In delayed DHRs the interplay between viruses and drugs is summarized according to the recent literature. The question is if the same reaction will again occur in case of drug re-exposure in absence of the concomitant viral infection because of persistent immune reactivity. Epstein Barr Virus (EBV) and Human Herpes virus 6 (HHV-6) models are analyzed in case of maculopapular exanthemas (MPEs) and drug reaction with eosinophilia and systemic symptoms (DRESS) over a course of drug therapy. MPEs are the most common skin manifestation during a viral infection and a concomitant drug therapy. In type IVb reactions to drugs a hapten/pro-hapten mechanism and a pharmacological interaction (p-i mechanism) are described as the 2 major ways to make T cells response functional. Rarely the altered repertoire model is involved. The Human Leukocyte Antigen (HLA) predisposition is an additional essential factor that can facilitate DHR. In MPEs rarely a DHR is confirmed by allergy testing. Severity and duration of MPEs, the presence of eosinophilia and systemic symptoms make more reliable the persistent nature of the reaction. Research on this topic is needed in order to provide the clinicians with instruments to decide when to suspect future reactions upon drug re-exposure even in the absence of a viral infection, because those patients should be investigated by a complete drug allergy work up.