Purpose Tolerance to shrimp has been reported in some patients with a history of shrimp allergy. The predictors of the natural resolution of shrimp allergy have not been widely explored. This study aimed to investigate the role of specific IgE (sIgE) and specific IgG4 (sIgG4) to shrimp extracts and the cross-reactive shrimp allergens tropomyosin (TM), arginine kinase (AK) and myosin light-chain (MLC), as markers of persistent or resolved shrimp allergy (PSA or RSA). Methods Seventeen patients with a 10-year history of allergy to Penaeus monodon ( Pm ) and/or Macrobachium rosenbergii ( Mr ) were recruited. Oral shrimp challenges identified 10 patients with PSA and 7 patients with RSA. Sera from these patients were evaluated for sIgE and sIgG4 to Mr and Pm extracts as well as to TM, AK and MLC. Results The levels of sIgE to Mr and Pm extracts were lower in the RSA than in the PSA groups ( P = 0.05 and P = 0.008, respectively), but sIgG4 or sIgG4:sIgE ratio did not show statistical significance. The sIgE to AK and MLC, but not TM, were lower in the RSA group than in the PSA group ( P = 0.009 and P = 0.0008, respectively). There was no difference in sIgG4 to TM, AK and MLC between both groups. The ratio of sIgG4:sIgE to MLC, but not TM or AK, was higher in the RSA than in the PSA group ( P = 0.02). A higher diversity of sIgE to shrimp components was found in the PSA group than in the RSA group ( P = 0.006). Conclusions Specific bioassays can be used to identify patients with RSA. Oral shrimp challenges in these patients may provide a higher rate of passing the challenges and finally reintroducing shrimp in their diet.

RATIONALE: Shrimp is the most common cause of food hypersensitivity in adolescences and adults. Study on the natural history of shrimp allergy is scarce. The objective of this study is to examine the natural course of shrimp allergy and the predictor for its resolution. METHODS: Patients who were diagnosed as having shrimp allergy by positive oral food challenge (OFC) to Penaeus monodon (Pm) and Macrobrachium rosenbergii (Mr) were recruited. They were asked to repeat the second OFC after 10 years of follow up. The skin prick tests using extracts of Pm (PmSPT), Mr (MrSPT), and prick-to-prick tests of both shrimp species (PmPTP, MrPTP) were performed. RESULTS: Fourteen patients (aged 21.662.7 years) were evaluated. The previous reaction to Pm, Mr or both shrimp species were found in 7, 7 and 4 patients, respectively. The mean duration between the first and second OFC was 11.161.6 years. The second OFC were negative in 4/7 of Pm and 4/7 of Mr allergy. In patients who have positive OFC, 5/6 patients had less severe reactions. Two of eight patients who strictly avoided and 6/6 patients who did not strictly avoid shrimp in their diet could tolerate shrimp upon second OFC (p50.01). The skin test sizes were decreased in all patients. However, only MWD from MrSPT reduced significantly from 10.0 mm to 4.0 mm (p50.03). CONCLUSIONS: In this selected patients with shrimp allergy, about half of participants can outgrow. Predictive factor for shrimp tolerance was reintroducing shrimp into diets.

Background and aim: A precise scaling system of acute asthma leads to an accurate assessment of disease severity. This study aimed to compare the accuracy of the Buddhasothorn Asthma Severity Score (BASS) with the Wood–Downes–Ferrés Scale (WDFS) to recognize the severity level of acute asthma. Materials and methods: A cross-sectional study was conducted comprising Thai children aged 2–15 years with acute asthma. The BASS and WFDS were rated once in the emergency department. The degree of severity was determined by frequency and type of nebulized bronchodilator administrations at the time of initial treatment. The optimum cutoff points for the area under the curve (AUC) were established to predict severe asthma exacerbations. Results: All 73 episodes of asthma exacerbations (EAEs) in 35 participants were analyzed. Fifty-nine (80.8%) EAEs were classified as severe. Both scales had good significance to recognize the selection of nebulized bronchodilator treatments by AUC of 0.815 (95% Confidence Interval [CI]: 0.680–0.950) in case of BASS, and AUC of 0.822 (95% CI: 0.70–0.944) in case of WDFS. Cutoff points of BASS ≥ 8 had sensitivity 72.9%, specificity 64.3%, positive predictive value (PPV) 89.6%, negative predictive value (NPV) 36.0% at an AUC of 0.718 (95% CI: 0.563–0.873) for severe exacerbations. These results were consistent for cutoff points of WDFS ≥ 5 with sensitivity 78.0%, specificity 50.0%, PPV 86.8%, NPV 35.0% at an AUC of 0.768 (95% CI: 0.650–0.886) for predicting severe exacerbations. There was no significant difference between the AUCs of both scales. Conclusions: Both the BASS and WDFS were good and accurate scales and effective screening tools for predicting severe asthma exacerbations in pediatric patients by optimal cutoff points.