Introduction |Shellfish allergy is an important cause of food allergies worldwide. Both in vivo and in vitro diagnostics failure nowadays is caused by the poor quality of the extracts associated with the scarce availability of allergenic molecules in the market. It is known that not all patients with shellfish allergies experience adverse reactions to mollusks. It is still unclear how to detect and diagnose correctly these patients. Aim |To investigate the features of shrimp-allergic patients either reactive or tolerant to mollusks, with the currently available diagnostic methods. Methods| Nineteen centers, scattered throughout Italy, participated in the study, enrolling patients allergic to shrimp with or without associated reactions to mollusks. Patients underwent skin tests using commercial extracts or fresh raw and cooked foods, and IgE reactivity to currently available allergenic extracts and molecules was measured in vitro. Results| Two hundred and forty-seven individuals with a history of adverse reaction to crustaceans participated in the study. Only 47.8% of them reacted after cephalopod or bivalve ingestion. None of the tests used, either in vivo or in vitro, was able to detect all selected patients. Accordingly, a great heterogeneity of results was observed with an agreement between in vivo and in vitro tests ranging between 52% and 62% of cases. Skin tests were able to identify the cephalopod and bivalve reactors (p <0.001), also using fresh cooked or raw food (p <0.001). The reactivity profile of mollusk reactors was dominated by Pen m 1, over Pen m 2 and Pen m 4 compared to the tolerant subjects, but 33% of patients allergic to shellfish were not detected by any of the available molecules. A higher frequency of shrimp hypersensitivity was recorded in northern Italy, while mollusk reactivity was more frequent in the center-south. Conclusion |The current diagnostic methods are inadequate to predict the cross-reactivity between crustaceans and mollusks. The detection of mollusks hypersensitivity must still rely on skin tests with fresh material. There is no need to exclude mollusks from shrimp allergic patients’ diet unless clinical history, the available diagnostic instruments, and/or tolerance tests support such a decision. Primary sensitization to mollusks seems possible.

IgE sensitization profile in patients withNetherton syndromeEnrico Scalaa, Angelo Giuseppe Condorellib, Alessandro Scalac, Elisabetta Caprinia, Biagio Didonaa, Roberto Paganellid, Daniele Castigliae,aClinical and Laboratory Molecular Allergy Unit – IDI - IRCCS, Rome, ItalybGenodermatosis Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital, IRCCS, Rome, ItalycFondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore – ROMA, ItaliadInternal Medicine,  UniCamillus, International Medical University, 00131 Rome, Italy.eLaboratory of Molecular and Cell Biology, IDI-IRCCS, Rome, Italy

Abstract The coronavirus disease (COVID-19), during its course, may involve several organs, including the skin with a petechial skin rash, urticaria and erythematous rash, or varicella-like eruption, representing an additional effect of the SARS-CoV-2 infection, as commonly observed in other viral diseases. Considering that symptomatic COVID-19 patients generally undergo multi-drug treatments, the occurrence of a possible adverse drug reaction (ADR) presenting with cutaneous manifestations should be contemplated. Pleomorphic skin eruptions occurred in a 59-year-old Caucasian woman, affected by a stable form of Chronic lymphocytic leukaemia, and symptomatic SARS-CoV.2 infection, treated with a combination of hydroxychloroquine sulphate, darunavir, ritonavir, sarilumb, omeprazole, ceftriaxone, high-flow oxygen therapy devices, filgrastim (Zarzio®) as a single injection, and enoxaparin. The patient stopped all treatment but oxygen and enoxaparin and received a high-dose Desametasone with complete remission of dermatological impairment in 10 days. It is very important to differentially diagnose COVID-19 disease-related cutaneous manifestations, where is justified to continue the multi-drug antiviral treatment, from those caused by an adverse drug reaction, where it would be necessary to identify the possible culprit drug and to start an appropriate treatment.

BACKGROUND: Severe Covid-19 is associated with a cytokine storm leading to the hyper-expression of cytokines such as IFN-gamma, TNF-alpha, and IL-6, which may be responsible for most severe symptoms and signs of the disease. The immune response of the atopic patient is mostly Th2-oriented, associated with the expression of cytokines such as IL-4, IL-5, and IL-13, and atopic patients express fewer ACE-2 receptors than non-atopic individuals do. We assessed whether atopic status may protect from the most severe consequences of Covid-19. METHODS: Atopic status along with co-factors such as diabetes, hypertension, coronary heart disease, and thrombosis was investigated in severe Covid-19 patients admitted to different Italian hospitals. Patients were classified as having a mild, severe, or very severe disease based on the need of respiratory assistance; severity was plotted against the different co-factors and underwent multivariate analysis. RESULTS: 531 adults aged 25 - 100 years were studied; 57 (11.7%) were atopic. Atopic status showed a significant association with a milder disease irrespective of all other co-factors considered (p <0.001); the protective effect of atopy was detectable throughout all age groups (p< 0.001). CONCLUSIONS: Atopic status appears to protect from the most severe consequences of Covid-19.