Evaluation of the relationship between mast cell activation and postural orthostatic tachycardia syndrome in children and adolescents.

OBJECTIVE: Postural orthostatic tachycardia syndrome (POTS) is one of the orthostatic intolerance syndromes that are common in young adolescents and impair quality of life. POTS is a multi-systemic disease. Many mechanisms have been defined in POTS etiology, such as autonomic denervation, hypovolemia, hyperadrenergic stimulation, low condition, and hypervigilance. Recently, mast cell activation (MCA) has also been on the agenda in etiology. There are few studies in the literature on the relationship between MCA and POTS in adulthood. However, data on children and adolescents is limited. In light of this information, we aimed to evaluate the relationship between POTS and MCA by measuring serum tryptase levels, a specific marker for MCA. METHODS: This prospective study included patients who were admitted to Kocaeli University Faculty of Medicine Hospital Pediatric Cardiology outpatient clinic for syncope-presyncope between November 2018 and August 2019. Patients who underwent the TILT-table test were enrolled in the study. Patients with structural heart disease or chronic heart disease were not included in this study. Serum tryptase levels were obtained from all patients before the TILT-table test, and serum tryptase levels were re-studied after the test was terminated in patients with positive TILT-table tests for POTS. Patients diagnosed with POTS were classified as Group 1, and other patients were classified as Group 2. RESULTS: Twenty-eight of the 58 patients included in the study (mean: 14.4±2.0 years; 38 girls, 20 boys) were diagnosed with POTS. The remaining 30 patients were diagnosed with vasovagal syncope and included in Group 2. The increase in mean heart rate during the test was 38±6 beats/min and 47.05%±15.65% in patients with POTS. Basal serum tryptase levels were not different between groups (3.2±1.3 ng/ml and 3.84±1.78 ng/ml, respectively; p=0.129), while serum tryptase levels (both baseline and after 45-60 min of the TILT-table test) were higher in patients presenting with symptoms related to MCA compared to others. CONCLUSION: In the literature, MCA was considered to be one of the mechanisms leading to POTS. Although other mechanisms, such as neuropathic and hypovolemic POTS, may be active in the patients, the symptoms of MCA in these patients should be routinely questioned.

Prospective evaluation of tolerance to unheated milk-boiled egg after baked milk-egg tolerance under 2 years.

BACKGROUND: The time to acquisition of tolerance to unheated milk and regular egg after achievement of tolerance to baked goods is not known. OBJECTIVE: To determine the time to acquisition of unheated-milk-regular-egg tolerance, after the tolerance of the baked forms, in children younger than 2 years. METHODS: An initial oral food challenge with baked milk (BM) and baked egg (BE) was performed on patients who were reactive to unheated milk-regular egg, respectively. Patients who were BM-BE tolerant were offered unheated-milk-regular-egg challenges, and patients who were BM-BE reactive were offered BM-BE challenges at an average of 3-month intervals. Food-induced atopic dermatitis was included. RESULTS: Thirty-six children with unheated-milk allergy (median age, 7.3 months [interquartile range (IQR), 6.0-13.5]) and 65 with regular-egg allergy (median age, 7 months [IQR, 5.8-11.0]) were included. Seven of 13 children who were BM tolerant acquired unheated-milk tolerance after a median 4.0 months (IQR, 2.0-7.0). Twelve of 23 children who were BM reactive acquired unheated-milk tolerance after a median 5.0 months (IQR, 3.0-8.0) after BM tolerance. Twenty-one of 29 children who were BE tolerant acquired regular-egg tolerance after a median 3.0 months (IQR, 1.0-6.0). Sixteen of 36 children who were BE reactive acquired regular-egg tolerance after a median 4.0 months (IQR, 2.0-6.8) after BE tolerance. CONCLUSION: Different tolerance rates were determined for baked products at different time points in the first 2 years of life. Unheated-milk-regular-egg allergy resolved in up to 65.5% and 75.5% of cases, respectively, in an average 4 to 5 months after acquisition of BM-BE tolerance. Baked-milk-baked-egg tolerance may be regarded as a precursor of tolerance.

A Prospective Assessment of Clinical Characteristics and Responses to Dietary Elimination in Food Protein-Induced Allergic Proctocolitis.

BACKGROUND: Some aspects of diagnostic elimination/challenge diets in food protein-induced allergic proctocolitis (FPIAP) are still poorly defined. OBJECTIVE: This study investigated the symptom spectrum, time required for resolution of each symptom, triggering foods, and risk factors for multiple food allergies (MFA) in FPIAP. METHODS: Infants referred with visible blood in stool were enrolled after etiologies other than FPIAP had been excluded. Laboratory evaluation, clinical features, and elimination/challenge steps were performed prospectively during diagnostic management. RESULTS: Ninety-one of 102 infants (53 boys) were diagnosed with FPIAP. Eleven children did not bleed during challenges. Visible blood in stool began before 2 months of age in 63.6% of the infants not diagnosed with FPIAP, compared with 18.9% of the patients with FPIAP (P = .003). Offending foods were identified as cow's milk (94.5%), egg (37.4%), beef (10.9%), wheat (5.5%), and nuts (3.3%). MFA was determined in 42.9% of patients. Multivariate logistic regression analysis identified atopic dermatitis (AD) (odds ratio [OR]: 2.98, 95% confidence interval [CI]: 1.18-7.55, P = .021) and an eosinophil count ≥300 cells/µL (OR: 2.72, 95% CI: 1.09-6.80, P = .032) as independent risk factors for MFA. Blood and mucus in stool disappeared in a median 3 days (interquartile range [IQR]: 1-14.5 days) and 30 days (IQR: 8-75 days), respectively. CONCLUSIONS: A tendency to transient bleeding occurs in infants who present with bloody stool before 2 months of age. A 2-week duration of elimination for blood in stool is sufficient to reach a judgment of suspected foods for FPIAP. Mucus in stool is the last symptom to disappear. Concurrent AD suggests a high probability of MFA in FPIAP.

Are large local reactions a marker for systemic reactions to subcutaneous immunotherapy in children?

BACKGROUND: Previous studies involving predominantly adults concluded that the patients developing frequent large local reactions (LLRs) might be at greater risk for systemic reactions (SRs) during subcutaneous allergen immunotherapy (SCIT). OBJECTIVE: To determine the rate of side effects to SCIT and evaluate frequency of LLR among pediatric patients with SRs. METHODS: The retrospective study included pediatric patients receiving SCIT. Data on the demographic features, season at onset of SCIT, the indication for treatment, additional allergic diseases, laboratory results, the allergens applied, side effects after injection, grade of SRs, and the total number of injections for each patient were collected retrospectively from the medical records and injection charts. RESULTS: A total of 19,562 injections were administered to 261 patients with conventional SCIT. The incidence LLRs was 0.2% per injection; 1.15% of all patients (n = 3) experienced LLRs on at least two consecutive visits. Systemic side effects were seen in 1% of all SCIT injections. No grade 3 or grade 4 SRs were observed. Logistic regression analysis showed that having an LLR was 3.32 times (95% CI, 1.313-8. 440; P = 0.011) and initiation of SCIT in summer and spring was 4.309 and 3.056 times than autumn (95% CI, 1.527-12.157, P = 0.006; 95% CI, 1.358-6.849, P = 0.007), respectively, increased risk for an SR. CONCLUSIONS: Having LLRs might predict the risk of SRs at any time during immunotherapy in also pediatric patients. Knowing the risk factors is important for developing a personalized protocol in these patients.

Food-induced anaphylaxis in early childhood and factors associated with its severity.

Background: Several factors that increase the risk of severe food-induced anaphylaxis have been identified. Objective: We aimed to determine the demographic, etiologic, and clinical features of food-induced anaphylaxis in early childhood and also any other factors associated with severe anaphylaxis. Methods: We carried out a medical chart review of anaphylaxis cases from 16 pediatric allergy and immunology centers in Turkey. Results: The data of 227 patients with 266 food-induced anaphylaxis episodes were included in the study. The median (interquartile range) age of the first anaphylaxis episode was 9 months (6-18 months); 160 of these patients were boys (70.5%). The anaphylaxis episodes were mild in 75 cases (28.2%), moderate in 154 cases (57.9%), and severe in 37 cases (13.9%). The most frequent food allergens involved were cow's milk (47.4%), nuts (16.7%), and hen's egg (15.8%). Epinephrine was administered in only 98 (36.8%) of these anaphylaxis episodes. A logistic regression analysis revealed two statistically significant factors that were independently associated with severe anaphylaxis: the presence of angioedema and hoarseness during the anaphylactic episode. Urticaria was observed less frequently in patients who developed hypotension. In addition, confusion and syncope were associated with 25.9- and 44.6-fold increases, respectively, in the risk of concomitant hypotension. Conclusion: Cow's milk, nuts, and hen's egg caused the majority of mild and moderate-to-severe anaphylaxis episodes. The presence of angioedema and hoarseness in any patient who presents with a history of food-induced anaphylaxis should alert clinicians that the reaction may be severe. In addition, the presence of confusion, syncope, or stridor probably indicates concomitant hypotension.