Leukotriene receptor antagonists as add-on therapy to antihistamines for urticaria: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The benefits and harms of adding antileukotrienes to H1-antihistamines for the management of urticaria (hives, itch, and/or angioedema) remain unclear. OBJECTIVE: We sought to systematically synthesize the treatment outcomes of antileukotrienes in combination with H1-antihistamines versus H1-antihistamines alone for acute and chronic urticaria. METHODS: As part of updating American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters urticaria guidelines, we searched MEDLINE, Embase, CENTRAL, LILACS, WPRIM, IBECS, ICTRP, CBM, CNKI, VIP, Wanfang, FDA, and EMA databases from inception to December 18th, 2023 for randomized controlled trials (RCTs) evaluating antileukotrienes and H1-antihistamines versus H1-antihistamines alone in patients with urticaria. Paired reviewers independently screened citations, extracted data, and assessed risk of bias. Random effects models pooled effect estimates for urticaria activity, itch, wheal, sleep, quality of life, and harms. The GRADE approach informed certainty of evidence ratings. Open Science Framework registration: https://osf.io/h2bfx/. RESULTS: Thirty-four RCTs enrolled 3,324 children and adults. Compared to H1-antihistamines alone, the combination of a leukotriene receptor antagonist (LTRA) with H1-antihistamines probably modestly reduces urticaria activity (mean difference: -5.04, 95%CI -6.36 to -3.71; 7-day Urticaria Activity Score) with moderate certainty. We made similar findings for itch and wheal severity, and quality of life. Adverse events were probably not different between groups (moderate certainty), however, no RCT reported on neuropsychiatric adverse events. CONCLUSION: Among patients with urticaria, adding LTRAs to H1-antihistamines probably modestly improves urticaria activity with little to no increase in overall adverse events. The added risk of neuropsychiatric adverse events in this population with LTRAs is small and uncertain.

Anaphylaxis: A 2023 practice parameter update.

This practice parameter update focuses on 7 areas in which there are new evidence and new recommendations. Diagnostic criteria for anaphylaxis have been revised, and patterns of anaphylaxis are defined. Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders. In infants and toddlers, age-specific symptoms may differ from older children and adults, patient age is not correlated with reaction severity, and anaphylaxis is unlikely to be the initial reaction to an allergen on first exposure. Different community settings for anaphylaxis require specific measures for prevention and treatment of anaphylaxis. Optimal prescribing and use of epinephrine autoinjector devices require specific counseling and training of patients and caregivers, including when and how to administer the epinephrine autoinjector and whether and when to call 911. If epinephrine is used promptly, immediate activation of emergency medical services may not be required if the patient experiences a prompt, complete, and durable response. For most medical indications, the risk of stopping or changing beta-blocker or angiotensin-converting enzyme inhibitor medication may exceed the risk of more severe anaphylaxis if the medication is continued, especially in patients with insect sting anaphylaxis. Evaluation for mastocytosis, including a bone marrow biopsy, should be considered for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis. After perioperative anaphylaxis, repeat anesthesia may proceed in the context of shared decision-making and based on the history and results of diagnostic evaluation with skin tests or in vitro tests when available, and supervised challenge when necessary.

Topical corticosteroids for hives and itch (urticaria): systematic review and Bayesian meta-analysis of randomized trials.

BACKGROUND: Topical corticosteroids are widely used as a treatment for itch and wheals (urticaria), but their benefits and harms are unclear. OBJECTIVE: To systematically synthesize the benefits and harms of topical corticosteroids for the treatment of urticaria. METHODS: We searched MEDLINE, EMBASE, and CENTRAL from database inception to March 23, 2024, for randomized trials addressing comparing topical corticosteroid to placebo for patients with urticaria (either chronic spontaneous or inducible urticaria or acute urticaria elicited from skin/intradermal allergy testing). Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects meta-analyses addressed urticaria severity, itch severity (numeric rating scale; range 0-10; higher is worse), and adverse events. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed certainty of evidence ratings. PROSPERO registration: CRD42023455182. RESULTS: Nineteen RCTs enrolled 379 participants with a median of mean age of 30.1 years (range 21.1 to 44.0). Compared to placebo, topical corticosteroids may reduce wheal size (ratio of means 0.47, 95%CI 0.38 to 0.59; low certainty) and itch severity (mean difference -1.30, 95%CI -5.07 to 2.46; very low certainty). Topical corticosteroids result in little to no difference in overall adverse events (94 fewer patients per 1000, 95%CrI 172 fewer to 12 more; high certainty). CONCLUSION: Compared to placebo, topical corticosteroids may result in a reduction of wheal size, and result in little to no difference in overall adverse events. Topical corticosteroids may reduce itch severity, but the evidence is very uncertain. Future large, randomized trials addressing the use of topical corticosteroids would further support optimal urticaria management.

Circulating anti-nuclear autoantibodies in COVID-19 survivors predict long COVID symptoms.

BACKGROUND: Autoimmunity has been reported in patients with severe coronavirus disease 2019 (COVID-19). We investigated whether anti-nuclear/extractable-nuclear antibodies (ANAs/ENAs) were present up to a year after infection, and if they were associated with the development of clinically relevant post-acute sequalae of COVID-19 (PASC) symptoms. METHODS: A rapid-assessment line immunoassay was used to measure circulating levels of ANAs/ENAs in 106 convalescent COVID-19 patients with varying acute phase severities at 3, 6 and 12 months post-recovery. Patient-reported fatigue, cough and dyspnoea were recorded at each time point. Multivariable logistic regression model and receiver operating curves were used to test the association of autoantibodies with patient-reported outcomes and pro-inflammatory cytokines. RESULTS: Compared to age- and sex-matched healthy controls (n=22) and those who had other respiratory infections (n=34), patients with COVID-19 had higher detectable ANAs at 3 months post-recovery (p<0.001). The mean number of ANA autoreactivities per individual decreased between 3 and 12 months (from 3.99 to 1.55) with persistent positive titres associated with fatigue, dyspnoea and cough severity. Antibodies to U1-snRNP and anti-SS-B/La were both positively associated with persistent symptoms of fatigue (p<0.028, area under the curve (AUC) 0.86) and dyspnoea (p<0.003, AUC=0.81). Pro-inflammatory cytokines such as tumour necrosis factor (TNF)-α and C-reactive protein predicted the elevated ANAs at 12 months. TNF-α, D-dimer and interleukin-1ß had the strongest association with symptoms at 12 months. Regression analysis showed that TNF-α predicted fatigue (ß=4.65, p=0.004) and general symptomaticity (ß=2.40, p=0.03) at 12 months. INTERPRETATION: Persistently positive ANAs at 12 months post-COVID are associated with persisting symptoms and inflammation (TNF-α) in a subset of COVID-19 survivors. This finding indicates the need for further investigation into the role of autoimmunity in PASC.

Epinephrine autoinjectors: individualizing device and dosage to optimize anaphylaxis management in the community setting.

Background: Anaphylaxis is the most severe manifestation of a systemic allergic reaction, and, in the community setting, the immediate administration of an epinephrine autoinjector (EAI) can be life-saving. Physicians are tasked with selecting the most appropriate EAI for each individual and counseling patients and/or their caregivers to maximize the likelihood of successful deployment of the EAI. Objective: To offer an evidence-based expert clinical perspective on how physicians might best tailor EAI selection to their patients with anaphylaxis. Methods: A group of eight adult and pediatric allergists with expertise in anaphylaxis management reviewed and assessed the published data and guidelines on anaphylaxis management and EAI device selection. Results: Personalized EAI selection is influenced by intrinsic individual factors, extrinsic factors such as the properties of the individual EAI (e.g., dose, needle length, overall design) as well as cost and coverage. The number and the variety of EAIs available have expanded in most jurisdictions in recent years, which provide a greater diversity of options to meet the characteristics and needs of patients with anaphylaxis. Conclusion: There currently are no EAIs with customizable dose and needle length. Although precise personalization of each patient's EAI remains an optimistic future aspiration, careful consideration of all variables when prescribing EAIs can support optimal management of anaphylaxis.

Demographic and clinical characteristics of patients with hereditary angioedema in Canada.

BACKGROUND: Data on the clinical and demographic features of Canadian patients with hereditary angioedema (HAE) are lacking. OBJECTIVE: To describe the clinical and demographic features in a large Canadian HAE cohort and compare them with patients with HAE in other countries. METHODS: An online questionnaire was distributed to the members of 2 Canadian HAE patient groups to collect information on demographics and HAE clinical characteristics. All participants 18 years of age or older with HAE type I or II were eligible. Frequency, location, prodromes, and triggers of HAE attacks, including types of HAE treatment, were characterized. RESULTS: Among the 90 participants who completed the online survey, 57% self-identified as having HAE type 1 and 26% HAE type II. The average diagnostic delay was 11 years. In the preceding 6 months, 24% of the participants had no attacks and 35% experienced greater than 5 attacks. The most frequently affected regions of the body were the abdomen (83%), arms orlegs (63%), face (41%), and larynx or throat (41%). Approximately 87% of the participants reported having access to C1 inhibitor at home, and 69% reported using it for long-term prophylaxis. CONCLUSION: Canadian patients with HAE share common clinical characteristics with patients with HAE in other countries. They had a delay in HAE diagnosis and a high burden of disease, as indicated by the high frequency of attacks in the preceding 6 months. This study provides a better understanding of the demographic and clinical characteristics of Canadian patients with HAE.

Interrupting reactivation of immunologic memory diverts the allergic response and prevents anaphylaxis.

BACKGROUND: IgE production against innocuous food antigens can result in anaphylaxis, a severe life-threatening consequence of allergic reactions. The maintenance of IgE immunity is primarily facilitated by IgG+ memory B cells, as IgE+ memory B cells and IgE+ plasma cells are extremely scarce and short-lived, respectively. OBJECTIVE: Our aim was to investigate the critical requirements for an IgE recall response in peanut allergy. METHODS: We used a novel human PBMC culture platform, a mouse model of peanut allergy, and various experimental readouts to assess the IgE recall response in the presence and absence of IL-4Rα blockade. RESULTS: In human PBMCs, we have demonstrated that blockade of IL-4/IL-13 signaling aborted IgE production after activation of a recall response and skewed the cytokine response away from a dominant type 2 signature. TH2A cells, identified by single-cell RNA sequencing, expanded with peanut stimulation and maintained their pathogenic phenotype in spite of IL-4Rα blockade. In mice with allergy, anti-IL-4Rα provided long-lasting suppression of the IgE recall response beyond antibody treatment and fully protected against anaphylaxis. CONCLUSION: The findings reported here advance our understanding of events mediating the regeneration of IgE in food allergy.

Prevention and management of allergic reactions to food in child care centers and schools: Practice guidelines.

Food allergy management in child care centers and schools is a controversial topic, for which evidence-based guidance is needed. Following the Grading of Recommendations Assessment, Development, and Evaluation approach, we conducted systematic literature reviews of the anticipated health effects of selected interventions for managing food allergy in child care centers and schools; we compiled data about the costs, feasibility, acceptability, and effects on health equity of the selected interventions; and we developed the following conditional recommendations: we suggest that child care centers and schools implement allergy training and action plans; we suggest that they use epinephrine (adrenaline) to treat suspected anaphylaxis; we suggest that they stock unassigned epinephrine autoinjectors, instead of requiring students to supply their own personal autoinjectors to be stored on site for designated at-school use; and we suggest that they do not implement site-wide food prohibitions (eg, "nut-free" schools) or allergen-restricted zones (eg, "milk-free" tables), except in the special circumstances identified in this document. The recommendations are labeled "conditional" due to the low quality of available evidence. More research is needed to determine with greater certainty which interventions are likely to be the most beneficial. Policymakers might need to adapt the recommendations to fit local circumstances.

Recent development on the use of sublingual immunotherapy tablets for allergic rhinitis.

OBJECTIVE: Allergic rhinitis (AR) is an immunoglobulin (Ig) E-mediated inflammatory condition that causes sneezing, nasal congestion, rhinorrhea, and nasal itch. Although subcutaneous immunotherapy for the treatment of AR has been in use and well established as a treatment modality, sublingual immunotherapy (SLIT) is increasingly considered to be the safer and more convenient alternative. Thus, the objective of this review is to describe recent findings pertaining to the use of SLIT tablets (SLIT-T) for AR. DATA SOURCES: A database search (PubMed.gov) for articles published between January 1, 2017, and February 9, 2021, was conducted using the following key words: "allergic rhinitis," AND-ed "sublingual immunotherapy." Included were randomized placebo-controlled trials. Other experimental design studies were excluded. STUDY SELECTIONS: A total of 11 randomized placebo-controlled trials were selected for full-text review and included in the analysis. All studies investigated the use of SLIT on patients with seasonal AR (4 tree pollen, 1 grass pollen, and 1 Japanese cedar) or perennial AR (3 house dust mite). RESULTS: Our review of 7 recently published randomized placebo-controlled trials with 2348 subjects receiving SLIT reported increased efficacy, safety, supportive immunologic parameters (IgE and IgG4 pre- and posttreatment levels), and improved quality of life. All studies excluded subjects with overlapping seasonal or perennial allergens, a history of moderate-to-severe uncontrolled asthma, or reduced lung function. CONCLUSION: Our review highlights that SLIT is a safe and effective treatment that considerably reduces symptoms and medication requirements in AR and improves quality of life.

Quality of life in patients with hereditary angioedema in Canada.

BACKGROUND: Hereditary angioedema (HAE) is associated with decreased quality of life (QoL), which has typically been measured using a generic non-disease-specific questionnaire. OBJECTIVE: We aimed to assess the QoL in patients with HAE type I and II in Canada using a previously validated HAE-specific questionnaire. METHODS: An online questionnaire was sent to the members of two Canadian HAE patient groups to collect data on demographics, HAE clinical course, and QoL scores. All patients 18 years of age or older with HAE type I or II were eligible. The impact of the available clinical factors on the QoL scores was evaluated. Multiple linear regression was performed using clinically relevant factors to predict HAE QoL outcome. RESULTS: Among the 72 patients in the study, the mean total HAE QoL score was 102 (±23) (SD) on a scale of 25 to 135, with higher scores indicating better QoL. Although the total QoL scores correlated positively with patients' level of satisfaction and perceived control (P < .001 for both), it correlated negatively with the number of acute attacks (P = .03). Yet, the types of treatment did not have an impact on the QoL. Predictors, including sex, comorbidities, and the number of attacks, only explained 12% of the variance in the total QoL scores. CONCLUSION: HAE continues to impair QoL in Canadian patients despite receiving recommended treatment. Although the frequency of attacks affects QoL, patients' experience with their HAE care also affects QoL substantially. The study highlights the importance of considering patients' experience with their HAE care as physicians develop an appropriate management plan.

Oral immunotherapy for peanut allergy (PACE): a systematic review and meta-analysis of efficacy and safety.

BACKGROUND: Oral immunotherapy is an emerging experimental treatment for peanut allergy, but its benefits and harms are unclear. We systematically reviewed the efficacy and safety of oral immunotherapy versus allergen avoidance or placebo (no oral immunotherapy) for peanut allergy. METHODS: In the Peanut Allergen immunotherapy, Clarifying the Evidence (PACE) systematic review and meta-analysis, we searched MEDLINE, EMBASE, Cochrane Controlled Register of Trials, Latin American & Caribbean Health Sciences Literature, China National Knowledge Infrastructure, WHO's Clinical Trials Registry Platform, US Food and Drug Administration, and European Medicines Agency databases from inception to Dec 6, 2018, for randomised controlled trials comparing oral immunotherapy versus no oral immunotherapy for peanut allergy, without language restrictions. We screened studies, extracted data, and assessed risk of bias independently in duplicate. Main outcomes included anaphylaxis, allergic or adverse reactions, epinephrine use, and quality of life, meta-analysed by random effects. We assessed certainty (quality) of evidence by the GRADE approach. This study is registered with PROSPERO, number CRD42019117930. RESULTS: 12 trials (n=1041; median age across trials 8·7 years [IQR 5·9-11·2]) showed that oral immunotherapy versus no oral immunotherapy increased anaphylaxis risk (risk ratio [RR] 3·12 [95% CI 1·76-5·55], I2=0%, risk difference [RD] 15·1%, high-certainty), anaphylaxis frequency (incidence rate ratio [IRR] 2·72 [1·57-4·72], I2=0%, RD 12·2%, high-certainty), and epinephrine use (RR 2·21 [1·27-3·83], I2=0%, RD 4·5%, high-certainty) similarly during build-up and maintenance (pinteraction=0·92). Oral immunotherapy increased serious adverse events (RR 1·92 [1·00-3·66], I2=0%, RD 5·7%, moderate-certainty), and non-anaphylactic reactions (vomiting: RR 1·79 [95%CI 1·35-2·38], I2=0%, high-certainty; angioedema: 2·25 [1·13-4·47], I2=0%, high-certainty; upper tract respiratory reactions: 1·36 [1·02-1·81], I2=0%, moderate-certainty; lower tract respiratory reactions: 1·55 [0·96-2·50], I2=28%, moderate-certainty). Passing a supervised challenge, a surrogate for preventing out-of-clinic reactions, was more likely with oral immunotherapy (RR 12·42 [95% CI 6·82-22·61], I2=0%, RD 36·5%, high-certainty). Quality of life was not different between groups (combined parents and self report RR 1·21 [0·87-1·69], I2=0%, RD 0·03%, low-certainty). Findings were robust to IRR, trial sequential, subgroup, and sensitivity analyses. INTERPRETATION: In patients with peanut allergy, high-certainty evidence shows that available peanut oral immunotherapy regimens considerably increase allergic and anaphylactic reactions over avoidance or placebo, despite effectively inducing desensitisation. Safer peanut allergy treatment approaches and rigorous randomised controlled trials that evaluate patient-important outcomes are needed. FUNDING: None.

Multidisciplinary Real-World Experience With Bilastine, a Second Generation Antihistamine

Introduction: Allergic conditions frequently require treatment with antihistamines. First-generation antihistamines can potentially interfere with restful sleep, cause "morning after" effects, impair learning and memory, and reduce work efficiency. Second-generation antihistamines, such as bilastine, have been demonstrated to decrease allergy symptoms effectively without causing night-time sleep disturbances and related adverse events. Method: A real-world case project was developed to help optimize patient care by recognizing the role bilastine can play for allergic conditions where antihistamine treatment is needed. The presented real-world patient cases conducted by the panel members are supported with evidence from the literature, where available. Any discussion concerning off-label use should be considered an expert opinion only. Results: The real-world cases presented here used bilastine in conditions such as perennial and seasonal allergic rhinitis, chronic urticaria, as well as urticarial vasculitis and pruritus associated with inflammatory skin conditions. The treated patients were between 9 and 76-years old providing information on a full spectrum of patients that require treatment with antihistamines. Conclusions: The presented real-world cases using the second-generation antihistamine, bilastine, demonstrated favorable outcomes for the treated patients. While effectively relieving symptoms, the antihistamine was reported to be safe and well-tolerated. J Drugs Dermatol. 2020;19(2)145-154. doi:10.36849/JDD.2020.4835

Canadian physician survey on the medical management of hereditary angioedema.

BACKGROUND: Hereditary angioedema (HAE) is a rare disease that has significant morbidity and may be potentially fatal because of airway obstruction. OBJECTIVE: To determine practice patterns in physicians treating HAE. METHODS: A survey was designed to determine HAE practice patterns among Canadian physicians. These physicians were identified by sending the survey to members of 3 physician organizations (Canadian Hereditary Angioedema Network, Canadian Society of Clinical Immunology and Allergy, and Canadian Hematology Society). RESULTS: Thirty-six physicians responded to the survey. Thirty-four physicians were included in the analysis. Most referrals to HAE-treating physicians were from family and emergency department physicians. The most common sites of swelling reported by patients to physicians were facial, peripheral, and abdominal. A mean of 53.9% of patients with type 1 and 2 HAE and 53.4% of patients with HAE with normal C1 esterase inhibitor were undergoing long-term prophylaxis. A mean of 41.9%, 19.4%, and 93.5% of respondents had some patients taking danazol, tranexamic acid, and C1-esterase inhibitor, respectively. Most physicians believed that severity and frequency of attacks were the most important determinants in deciding when to use prophylaxis. A mean of 88.2% of physicians used C1-esterase inhibitor to treat acute attacks and 79.4% used icatibant. All respondents were aware of HAE guidelines. CONCLUSION: Physicians are using guidelines to support their practice and using agents suggested by guidelines with confidence. C1 inhibitor is being used widely for prophylaxis and treatment of acute attacks along with icatibant. However, certain special patient populations may require additional focus in future guidelines.

Lifelong memory responses perpetuate humoral TH2 immunity and anaphylaxis in food allergy.

BACKGROUND: A number of food allergies (eg, fish, shellfish, and nuts) are lifelong, without any disease-transforming therapies, and unclear in their underlying immunology. Clinical manifestations of food allergy are largely mediated by IgE. Although persistent IgE titers have been attributed conventionally to long-lived IgE+ plasma cells (PCs), this has not been directly and comprehensively tested. OBJECTIVE: We sought to evaluate mechanisms underlying persistent IgE and allergic responses to food allergens. METHODS: We used a model of peanut allergy and anaphylaxis, various knockout mice, adoptive transfer experiments, and in vitro assays to identify mechanisms underlying persistent IgE humoral immunity over almost the entire lifespan of the mouse (18-20 months). RESULTS: Contrary to conventional paradigms, our data show that clinically relevant lifelong IgE titers are not sustained by long-lived IgE+ PCs. Instead, lifelong reactivity is conferred by allergen-specific long-lived memory B cells that replenish the IgE+ PC compartment. B-cell reactivation requires allergen re-exposure and IL-4 production by CD4 T cells. We define the half-lives of antigen-specific germinal centers (23.3 days), IgE+ and IgG1+ PCs (60 and 234.4 days, respectively), and clinically relevant cell-bound IgE (67.3 days). CONCLUSIONS: These findings can explain lifelong food allergies observed in human subjects as the consequence of allergen exposures that recurrently activate memory B cells and identify these as a therapeutic target with disease-transforming potential.

The Initiation of Th2 Immunity Towards Food Allergens.

In contrast with Th1 immune responses against pathogenic viruses and bacteria, the incipient events that generate Th2 responses remain less understood. One difficulty in the identification of universal operating principles stems from the diversity of entities against which cellular and molecular Th2 responses are produced. Such responses are launched against harmful macroscopic parasites and noxious substances, such as venoms, but also against largely innocuous allergens. This suggests that the established understanding about sense and recognition applied to Th1 responses may not be translatable to Th2 responses. This review will discuss processes and signals known to occur in Th2 responses, particularly in the context of food allergy. We propose that perturbations of homeostasis at barrier sites induced by external or internal subverters, which can activate or lower the threshold activation of the immune system, are the major requirement for allergic sensitization. Innate signals produced in the tissue under these conditions equip dendritic cells with a program that forms an adaptive Th2 response.

Evaluating a handbook for parents of children with food allergy: a randomized clinical trial.

BACKGROUND: Educational materials are needed to support parent management of and coping with childhood food allergy. OBJECTIVES: To evaluate whether a food allergy handbook can improve parental knowledge, confidence, and quality of life associated with the management of food allergy. METHODS: Participants included 153 parents of children diagnosed as having food allergy within the past 12 months who were recruited from hospital-based allergy clinics and food allergy organizations. Parents were randomly assigned to receive the food allergy handbook either after a baseline survey (handbook group) or at the conclusion of study participation (control group). Outcomes were assessed using online surveys at baseline, 2-week follow-up, and 2-month follow-up. RESULTS: Compared with parents in the control group, parents in the handbook group had significantly greater improvement in knowledge at the 2-week (mean difference, 2.92; 95% confidence interval [CI], 2.20-3.64; P < .001) and 2-month (mean difference, 2.46; 95% CI, 1.68-3.25; P < .001) follow-ups, significantly greater improvement in confidence at the 2-week (mean difference, 0.24; 95% CI, 0.09-0.39; P = .002) and 2-month (mean difference, 0.47; 95% CI, 0.30-0.63; P < .001) follow-ups, and significantly greater improvement in quality of life at the 2-month follow-up (mean difference, -0.48; 95% CI, -0.79 to -0.16; P = .004). Parents reported satisfaction with the content the handbook, with mean ratings of individual sections ranging from 2.7 to 3.2 on a 0- to 4-point scale and modal ratings of 3 (very useful). CONCLUSIONS: The food allergy handbook evaluated in this study is an effective parent resource to supplement physician management of food allergy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01914978.