A rare case of lysozyme-induced anaphylaxis in a child with egg allergy.

We report an unusual case of anaphylaxis induced by the lysozyme-containing over-the-counter-drug Lysopaine®, which contains 20 mg lysozyme hydrochloride and 1.5 mg cetylpyridinium chloride, in a 9-year-old child with allergy to hen's egg as well as multiple IgE-mediated food allergies. The involvement of lysozyme was confirmed by positive skin prick tests for Lysopaine® and the presence of specific IgE against lysozyme. Our case highlights the importance of properly educating allergic patients to recognize allergens, even minor ones. Despite the presence of lysozyme in various food and drug products, it is not necessarily perceived as an allergenic protein by patients with egg allergy, and the labeling may be misleading, thereby exposing patients to potentially severe reactions.

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy.

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

Egg allergy and yellow fever vaccination.

OBJECTIVE: Evaluate biomarkers capable of safely guiding Yellow fever vaccine (YFV) vaccination among individuals suspicious of hen's egg allergy, and identify factors associated with a higher risk for adverse events after immunization (AEAI). METHODS: Patients underwent skin prick test (SPT) for standardized allergens: whole egg, egg white, egg yolk; YFV (1:10 dilution; Biomanguinhos-Fiocruz), and intradermal test (IDT; YFV 0.02 mL, 1:100 dilution) and positive and negative controls. Serum levels of specific IgE (sIgE) for a whole egg, egg white, egg yolk, egg albumin, ovomucoid, lysozyme, and conalbumin (ImmunoCap®; ThermoFisher®) were obtained. Patients sensitized to YFV were submitted to YFV desensitization, and those negatives received YFV (0.5mL) and remained under surveillance for at least one hour. RESULTS: 103 patients were enrolled, 95% under 12 years old. 71% (81/103) of patients had reactions: 80% immediate, 11% mixed, and 9% delayed. There was an association between positive skin test results with YFV and the severity of the reaction (OR:7.64; 95%CI:1.61-36.32; p = 0,011). Only the presence of sIgE to ovomucoid was associated with clinical symptoms (p = 0,025). Thirty patients underwent the YFV desensitization protocol. CONCLUSION: There is a relationship between the positivity of the egg's components and the severity of the clinical reaction. Furthermore, the relationship between the positivity of the tests with the YFV and egg's components may show a tendency to look at ovomucoid and conalbumin, but it is not a certainty. Therefore, further studies are needed to confirm these associations, and for now, the authors still recommend using the vaccine for testing when necessary.

Basophil activation test as predictor of severity and threshold of allergic reactions to egg.

BACKGROUND: Identifying patients at risk of severe allergic reactions and/or low threshold of reactivity is very important, particularly for staple foods like egg. METHODS: One hundred and fifty children underwent double-blind placebo-controlled food challenge (DBPCFC) to baked egg (BE), skin prick testing and blood collection for serology and basophil activation test (BAT). Patients who passed BE DBPCFC underwent loosely cooked egg (LCE) DBPCFC. Severity of allergic reactions was classified following Practall guidelines and threshold dose was determined during DBPCFC. RESULTS: Sixty out of 150 (40%) children reacted to BE and 16 out of 77 (21%) to LCE on DBPCFC. Considering DBPCFC to BE, 23 children (38%) had severe reactions and 33 (55%) reacted to 0.13 g or less of egg protein (low threshold group). Two children (2 out of 16 = 12%) had severe reactions to LCE. Demographic, clinical and most immunological features were not significantly different between severe/non-severe BE reactors or low/high threshold groups. Severe BE reactors had higher ovomucoid-sIgE (p = .009) and higher BAT to BE (p = .001). Patients with lower threshold to BE had higher IgE-specific activity (p = .027) and BAT to egg (p = .007) but lower severity score (p = .008). Optimal cut-offs for ovomucoid-sIgE had 100% sensitivity, 35% specificity and 60% accuracy and for BAT 76% sensitivity, 74% specificity and 75% accuracy to identify BE severe reactors. Optimal cut-offs for specific activity had 70% sensitivity, 68% specificity and 69% accuracy and for BAT 70% sensitivity, 72% specificity and 71% accuracy to identify low threshold patients. CONCLUSIONS: BAT was the best biomarker to predict severity and threshold of allergic reactions to BE and can be useful when making decisions about management of egg allergy.

Safety of Oral Food Challenge for Individuals with Low Egg White and Ovomucoid-Specific IgE Antibodies.

INTRODUCTION: During an oral food challenge (OFC), there is a risk of adverse reactions, including anaphylaxis. Therefore, the physician should carefully conduct the OFC. This study aimed to evaluate the OFC results in individuals with low levels of egg white (EW)- and ovomucoid (OVM)-specific immunoglobulin E (sIgE) and the safety of a hen's egg (HE) OFC in these individuals. METHODS: A total of 2,058 individuals with low EW- or OVM-sIgE underwent HE-OFC at two institutions in Kumamoto prefecture, located in the western area of Japan, between January 1, 2017, and December 31, 2021, within 1 year of recorded sIgE measurements. The ImmunoCAP systems were used to measure sIgEs. The HE-OFC test was performed according to the 2017 Food Allergy Guidelines in an open and unblinded method. RESULTS: Five hundred and one individuals (24.3%) had low EW-sIgE levels (class 2 or lower), and 926 (45.0%) had low OVM-sIgE levels (class 2 or lower). Individuals with low EW-sIgE had lower total IgE and OVM-sIgE than did those with high EW-sIgE (greater than class 2). Those with low OVM-sIgE had lower total IgE and EW-sIgE than did those with high OVM-sIgE (greater than class 2). Among the individuals with low EW-sIgE, 86.4% (433/501 cases) passed the OFC without symptoms. Among the individuals with low OVF-sIgE, 82.6% (765/926 cases) passed the OFC without symptoms. CONCLUSION: More than 80% of individuals with suspected IgE-dependent HE allergy and low levels of EW- or OVM-specific IgE were able to consume at least a small amount of HE. As the OFC results are independent of the loading dose in cases with low EW- or OVM-sIgE, a medium-dose HE-OFC may be performed safely in individuals with no history of anaphylaxis.

Partial Egg Consumption Modifies the Diagnostic Performance of Allergy Tests to Predict Outcome of Double-Blind Placebo-Controlled Food Challenges to Egg.

BACKGROUND: Many children are consuming some egg when they are diagnosed with egg allergy. We hypothesized that egg consumption could modify the diagnostic performance of allergy tests. OBJECTIVE: To stratify diagnostic performance of tests according to egg consumption status. METHODS: The BAT2 study (NCT03309488) participants underwent oral food challenge (OFC), food-frequency questionnaires, skin prick test (SPT), specific immunoglobulin E (sIgE) and specific immunoglobulin G4 (sIgG4) and basophil activation test (BAT). RESULTS: At study entry, 45% of participants reported partial egg consumption ("consumers") and 55% were avoiding egg strictly ("avoiders"). Avoiders had larger SPT (P < .001), higher BAT to egg (P < .001), sIgE to egg white (EW; P = .001) and to ovalbumin (OVA; P = .001), but not to ovomucoid (P = .231). Consumers had higher levels of sIgG4 to all egg allergens (P < .001) than avoiders. In consumers, the test with the best diagnostic performance was BAT (area under the curve [AUC] = .912) followed by SPT to raw egg (AUC = 0.805), EW-sIgE (AUC = 0.738), and OVA-sIgE (AUC = 0.732). In avoiders, the best tests were BAT (AUC = 0.834) and EW-sIgE (AUC = 0.833) followed by OVA-sIgE (AUC = 0.793) and SPT to EW (AUC=0.789). Using 100% sensitivity and 100% specificity cut-offs, the proportion of patients requiring OFC were 33% for BAT, 53% for SPT to raw egg, 61% for OVA-sIgE, and 73% for EW-sIgE for consumers; and 73% for BAT, 79% for EW-sIgE, and 93% for SPT to EW for avoiders. CONCLUSIONS: The diagnostic performance of tests is influenced by the immunomodulatory effect of egg consumption. BAT is the most reliable test and reduced the need for OFC, particularly in partial egg consumers.

Updates in Food Allergy Prevention in Children.

Although significant evidence exists that feeding early has a role in the prevention of food allergy, this intervention in isolation may not be sufficient. Recent evidence highlights that early introduction of peanut specifically has had no significant impact on the populational prevalence of peanut allergy. Other factors that may contribute to food allergy prevention include regularity of ingestion once an allergen is introduced and consideration to the form in which the allergen is introduced (such as baked versus cooked egg). There are also many practicalities to early feeding and some discrepant viewpoints on these practicalities, which has led to poor implementation of early feeding strategies. In general, preemptive screening before food introduction is not recommended by most international allergy societies. Although there is little guidance to inform early introduction of allergens other than milk, egg, and peanut, the mechanism of sensitization is thought to be similar and there is no harm to early introduction. In terms of frequency and duration of feeding, there is little evidence to inform any concrete recommendations.

The role of basophil activation test and component-resolved diagnostics in the workup of egg allergy in children at low risk for severe allergic reactions: A real-life study.

BACKGROUND: The gold standard for diagnosing egg allergy in children is the oral food challenge (OFC). However, OFCs are time-consuming and risky procedures. Our study aimed to evaluate the utility of the basophil activation test (BAT) and component-resolved diagnostic in the diagnostic workup of children with egg allergy. METHODS: Overall, 86 children aged 6 months to 17 years, suspected of egg allergy, underwent OFC with boiled egg according to international standardized protocols. BAT and specific immunoglobulin E (sIgE) testing to component egg proteins (Gal d 1-4) were also performed. RESULTS: Of the 22 children who reacted to boiled egg, only one experienced anaphylaxis during the challenge. BAT was performed in samples obtained by 75 of the 86 patients of our cohort. Egg white and yolk protein extracts induced CD63 upregulation in the egg-allergic (EA) children compared with sensitized children that tolerated boiled egg (we registered an overall mean of CD63 expression in the EA population of 44.4% [SD 34.1] for egg white and 34.7% [SD 31.3] for egg yolk vs. 12.5% [SD 19.1] and 10.0% [SD 16.0] in sensitized children). BAT could discriminate between true egg allergy and egg sensitization in our population. As a second-line diagnostic step, the positivity of BAT for egg white or Gal d 1-sIgE resulted in a 40.9% OFC reduction, especially for those with a positive outcome. CONCLUSION: The BAT may be implemented in the diagnostic workup of egg allergy in children and, in a stepwise approach, separately or combined with Gal d 1-sIgE, may predict the allergic status and reduce the number of positive OFCs in children with egg allergy at low risk for severe reactions.

Diagnostic utility of allergy tests to predict baked egg and lightly cooked egg allergies compared to double-blind placebo-controlled food challenges.

BACKGROUND: Double-blind placebo-controlled food challenges (DBPCFC) are the gold-standard to diagnose food allergy. However, they can cause allergic reactions of unpredictable severity. We assessed accuracy of current and new diagnostic tests compared to DBPCFC to baked egg (BE) and to lightly cooked egg (LCE). METHODS: Children aged 6 months to 15 years were assessed for possible egg allergy as part of the BAT2 study (NCT03309488). They underwent clinical assessment, skin prick test (SPT), specific IgE (sIgE) and basophil activation test (BAT). The results of the tests were compared with DBPCFC outcomes to both BE and LCE. RESULTS: A total of 150 children underwent DBPCFC to BE, 60 (40%) reacted to and 85 (57%) tolerated BE and 5 (3%) had inconclusive oral food challenges (OFC). Seventy-seven children tolerant to BE had DBPCFC to LCE and 16 reacted. The test within each modality with the best diagnostic performance for BE allergy was as follows: SPT to egg white (EW) (AUC = 0.726), sIgE to EW (AUC = 0.776) and BAT to egg (AUC = 0.783). BAT (AUC = 0.867) was the best test in the younger than 2 years age group. Applying 100% sensitivity and 100% specificity cut-offs, followed by OFC, resulted in 100% diagnostic accuracy. BAT enabled the greatest reduction in OFC (41%). Using sIgE followed by BAT allowed to reduce the number of BATs performed by about 30% without significantly increasing the number of OFC. CONCLUSIONS: The best diagnostic test was BAT to egg in terms of diagnostic accuracy and reduction in number of OFC. Using sIgE to EW followed by BAT required fewer BATs with sustained OFC reduction and diagnostic accuracy.

Component-Resolved Analyses for Diagnosis of Food Allergies in Infants and Young Children in Southern China.

INTRODUCTION: Chicken eggs and cow's milk are two of the most common foods that cause allergic reactions in infants and young children, and there is a lack of precise diagnostic methods to identify the allergic state of these patients. The recently developed food allergen component-resolved diagnosis (CRD) may be a more accurate diagnosis method for food allergies. METHODS: One hundred children sensitized to egg white and milk crude extracts and diagnosed with or suspected allergic disease were included. The specific immunoglobulin E (sIgE) (s) of animal food allergen crude extracts (egg yolk, milk, shrimp, crab, cod, beef) and the main components of egg white and milk were tested. The sensitization characteristics, cross-reactivity, and clinical relevance were analyzed. RESULTS: The results of egg white-sensitized patients showed that ovalbumin (Gal d 2) had the highest positive rate of 100%. Compared with other pairwise combinations of egg allergens, the combination of egg white and Gal d 2 had higher diagnostic accuracy, with an AUC of 0.876 (95% CI: 0.801-0.951), a sensitivity of 88.9%, and a specificity of 75.9%. The positive rates of beta-lactoglobulin (Bos d 5) and alpha-lactoglobulin (Bos d 4) in the milk-sensitized children were comparable, 92% and 91%, respectively. The combination of crude milk extract and Bos d 4 had the highest diagnostic accuracy, with an AUC of 0.969 (95% CI: 0.938-0.999), a sensitivity of 100%, and a specificity of 82.7%. CONCLUSION: Among these subjects, our study found the main allergenic component of egg white was Gal d 2, and the main allergenic components of milk were Bos d 4 and Bos d 5. CRD may help identify egg/milk allergies and non-allergies.

Phenotypes of persistent hen`s egg allergy in children and adolescents.

BACKGROUND: Optimum management of food allergy (FA) includes consideration of co-allergies and multimorbidities and tolerance assessment. Documentation of FA practices may pave the way for better practice. METHODS: Patients aged 3-18 years, with persistent IgE-mediated hen`s egg allergy were reviewed. RESULTS: A total of 102 children with a median age of 59 months (IQR= 40-84) (72.2% males) were included. All were diagnosed during infancy and the initial symptoms were atopic dermatitis (65.6%), urticaria (18.6%), and anaphylaxis (5.9%). Of the total population, 21 (20.6%) experienced anaphylaxis with hen`s eggs, and 79.4%, 89.2%, and 30.4% had multiple FAs (≥2 food categories), ever atopic dermatitis, and asthma, respectively. The most common co-allergies were tree nuts, cow`s milk, and seeds, respectively. From 52 heated egg yolk and 47 baked egg oral food challenges, 48 (92.3%) and 41 (87.2%) were found as tolerant, respectively. The baked egg nontolerant group had a greater egg white skin prick test diameter [9 mm (IQR: 6-11.5) vs. 6 mm (IQR: 4.5-9); (p=0.009)] and specific IgE [12.6 kU/L (IQR: 4.11-45.4) vs. 6.2 kU/L (IQR: 1.9-12.4) (p=0.009)], respectively. In the multivariate analysis, baked egg tolerance was more likely in those with egg yolk-tolerant subgroup (OR: 6.480, 95% CI: 2.524-16.638; p < 0.001) and heated egg tolerance in those with baked egg tolerance (OR: 6.943, 95% CI: 1.554-31.017; p=0.011). CONCLUSIONS: Persistent hen`s egg allergy is characterized by multiple food allergies and age-related multimorbidities. Baked egg and heated egg yolk tolerance were more likely to be considered in a subgroup with a high expectation for finding a way to eliminate their allergy.

Effect of moderate to severe atopic dermatitis on the prognosis of egg allergy resolution

BACKGROUND: Few studies have examined the effect of atopic dermatitis (AD) on the resolution of food allergies in Asia, and the predictors of egg allergy resolution are not yet well defined. OBJECTIVE: We evaluated whether AD severity could predict the resolution of egg allergy. METHODS: This retrospective cohort study included infants under 24 months of age diagnosed with IgE-mediated egg white allergy. We included subjects who completed a 60-month follow-up. Open oral food challenges (OFCs) and serologic tests were performed at the time of initial diagnosis and at 36 ± 3 and 60 ± 3 months. RESULTS: We analyzed 68 patients (39 boys and 29 girls). OFCs were performed in 88.2% of the patients. The egg allergy remission rates were 23.5% and 47.1% by 3 and by 5 years of age, respectively. Persistent egg allergy was significantly associated with moderate to severe AD and house dust mite sensitization. Kaplan-Meier curve analysis revealed that patients with moderate to severe AD had higher persistent egg allergy rates than patients with no and mild AD (p = 0.012). Multivariable analysis identified moderate to severe AD as strongly associated with persistent egg allergy (p = 0.001). CONCLUSIONS: In this study, 47.1% of infants had resolved egg white allergies at 60 months. Moderate to severe AD may be a practical and important prognostic factor for persistent egg allergy in clinical settings.

Phenotyping of immediate-type food allergies based on 10 years of research: A latent class analysis.

BACKGROUND: Food allergy is a disease with a diverse and variable natural history, and some patients may react to two or more food antigens. This study aimed to classify and characterize the long-term prognosis of infantile-onset, immediate-type food allergies, focusing on three major antigens in Japan: egg, milk, and wheat. METHODS: All children who visited our hospital with food allergies, including suspected cases, were prospectively registered in our medical database. Among the children in this database, subjects registered by the age of 1 year with immediate-type symptoms or sensitization to the above three antigens were included. The course of the subjects up to the age of 6 years was analyzed. Cox regression analysis and repeated-measures latent class analysis (LCA) were performed to reveal risk factors and tolerance patterns for food allergies. RESULTS: We included 915 patients with immediate-type food allergy symptoms and 276 sensitized asymptomatic patients in this study. The number of patients with immediate-type symptoms to egg, milk, and wheat was 609, 443, and 235, respectively. The number of patients with multiple food allergies was 302. The proportion of patients with tolerance to egg, milk, and wheat at 6 years of age was 74%, 69%, and 75%, respectively. LCA revealed 7 classes of prognosis for food allergies. The largest class was transient egg allergy alone (19.6%), and there were severe cases of multiple food allergies (6.5%). CONCLUSIONS: This study demonstrated the prognosis of food allergy classes in Japan, including multiple food allergies, with 7 classes with its own characteristics.

[CLINICAL MANIFESTATIONS AND SAFETY OF AN ORAL FOOD CHALLENGE USING BOILED EGG YOLK].

BACKGROUND: Allergenicity to heated egg yolks is known to be low in hen's egg allergy. However, there are few reports concerning the safety of an oral food challenge (OFC) with boiled egg yolks. This study aimed to determine the safety of a boiled egg yolk OFC and the clinical characteristics of patients who were OFC-positive. METHODS: We retrospectively examined the data of patients who underwent an OFC with one boiled egg yolk at Miyagi Children's Hospital between January 2013 and December 2020. Patients were included if they had a history of immediate symptoms due to hen's egg or positive specific IgE levels to egg yolk or egg white. RESULTS: Among 600 patients, 15.0% were positive for OFC, only one patient required an intramuscular adrenaline injection, and 70% of OFC-positive patients had gastrointestinal symptoms. CONCLUSION: Boiled egg yolk OFC had a low symptom induction rate; however, when symptoms were induced, gastrointestinal symptoms were most commonly observed. Given the low risk of developing severe symptoms, we conclude that the likelihood of safely performing an OFC is high.

The natural history of peanut and egg allergy in children up to age 6 years in the HealthNuts population-based longitudinal study.

BACKGROUND: Prospectively collected data on the natural history of food allergy are lacking. OBJECTIVE: We examined the natural history of egg and peanut allergy in children from age 1 to 6 years and assessed whether a skin prick test (SPT) result or other clinical factors at diagnosis are associated with the persistence or resolution of food allergy in early childhood. METHODS: The HealthNuts cohort consists of 5276 children who were recruited at age 1 year and have been followed prospectively. Children with food allergy at age 1 year (peanut [n = 156] or raw egg [n = 471] allergy ) and children who developed new sensitizations or food reactions after age 1 year were assessed for food sensitization and allergy (confirmed by oral food challenge when indicated) at the 6-year follow-up. RESULTS: New-onset food allergy developed by age 6 years was more common for peanut (0.7% [95% CI = 0.5%-1.1%]) than egg (0.09% [95% CI = 0.03%-0.3%]). Egg allergy resolved more commonly (89% [95% CI = 85%-92%]) than peanut allergy (29% [95% CI = 22%-38%]) by age 6 years. The overall weighted prevalence of peanut allergy at age 6 years was 3.1% (95% CI = 2.6-3.7%) and that of egg allergy was 1.2% (95% = CI 0.9%-1.6%). The factors at age 1 year associated with persistence of peanut allergy were peanut SPT result of 8 mm or larger (odds ratio [OR] = 2.35 [95% CI 1.08-5.12]), sensitization to tree nuts (adjusted OR [aOR] = 2.51 [95% CI = 1.00-6.35]), and early-onset severe eczema (aOR = 3.23, [95% CI 1.17-8.88]). Factors at age 1 associated with persistence of egg allergy at age 6 were egg SPT result of 4 mm or larger (OR = 2.98 [95% CI 1.35-6.36]), other (peanut and/or sesame) food sensitizations (aOR = 2.80 [95% CI = 1.11-7.03]), baked egg allergy (aOR = 7.41 [95% CI = 2.16-25.3]), and early-onset severe eczema (aOR = 3.77 [95% CI = 1.35-10.52]). CONCLUSION: Most egg allergy and nearly one-third of peanut allergy resolves naturally by age 6 years. The prevalence of peanut allergy at age 6 years was similar to that observed at age 1 year, largely owing to new-onset food peanut allergy after age 1 year. Infants with early-onset eczema, larger SPT wheals, or multiple food sensitizations and/or allergies were less likely to acquire tolerance to either peanut or egg.

[ANAPHYLACTIC REACTION TO LYSOZYME CHLORIDE-INCLUDING DEODORANT SPRAY IN A CHILD WITH EGG ALLERGY].

BACKGROUND: Lysozyme chloride is a bactericidal substance that is included as an active ingredient in many medicines and quasi-drugs. We experienced a case of anaphylactic reaction caused by deodorant spray-containing lysozyme chloride. CASE: The patient was a 10-year-old girl who had an egg allergy. She visited an emergency department because of urticaria, wheezing, dyspnea, and pallor after she used deodorant spray that contained lysozyme chloride derived from hen's egg white. Results for deodorant spray and lysozyme chloride were positive in both skin prick tests and basophil activation tests. According to the medical history and the results, her condition was diagnosed as an anaphylactic reaction to lysozyme chloride in the deodorant spray. DISCUSSION: Although ingredient labelling is obligatory for lysozyme chloride in quasi-drugs, lysozyme chloride is not often described to be derived from egg white. It is important to alert patients with egg allergy to avoid lysozyme chloride-containing products.