Correlation between the expression of the iNOS, caspase-3 and α-SMA genes in the parotid glands of albino rats following the administration of two antihistamines from two different generations.

BACKGROUND: Several medications, including antihistamines, can alter salivary gland function, causing dry mouth or xerostomia. Antihistamines are commonly used for treating allergic rhinitis. OBJECTIVES: The aim of the present study was to compare and correlate the effects of first-generation vs. second-generation H1-antihistamines on the parotid glands of rats. MATERIAL AND METHODS: Twelve adult male albino rats were used; 4 rats served as a control group (group I) and the remaining rats were divided into 2 groups: group II received promethazine hydrochloride; and group III received cetirizine dihydrochloride for 3 weeks. The parotid salivary glands were dissected, and examined histologically and analyzed histomorphometrically for the acinar area percentage. In addition, mRNA gene expression of iNOS, caspase-3 and α-SMA was assessed using quantitative realtime polymerase chain reaction (qRT-PCR). Finally, all the obtained data was statistically analyzed. RESULTS: Histologically, group I showed the typical architecture of the gland. In group II, degenerative changes were noticed, including acinar degeneration and shrinkage with widened connective tissue septa, intracellular vacuolization, and increased inflammatory cell infiltration. In group III, similar histological features were detected as in group II, but to a lesser extent. Histomorphometric results revealed significant differences in the acinar area percentage between various groups. In addition, qRT-PCR results showed a significant increase in iNOS expression in both groups II and III as compared to group I, caspase-3 gene expression was significantly increased in group II, while in group III, it increased non-significantly. Finally, α-SMA gene expression non-significantly decreased in both groups II and III. A significant positive correlation was observed between caspase-3 and iNOS gene expression, while an inverse correlation was noticed between caspase-3 and α-SMA gene expression. CONCLUSIONS: The administration of antihistamines resulted in changes in the rat salivary glands, which could be due to the induction of oxidative stress and the resultant apoptotic effect. These changes were suggested to occur mainly through action on muscarinic receptors; yet, action on histamine receptors could not be excluded. However; these effects were less marked with the second-generation antihistamine.

Current insights on gut microbiome and chronic urticaria: progress in the pathogenesis and opportunities for novel therapeutic approaches.

Chronic urticaria (CU) is a prevalent skin disorder greatly impacting the patients' life quality, in which immune dysregulation mediated by gut microbiome plays a significant role. Several studies have found the gut dysbiosis exists in patients with CU. In addition, infection may also be one of the causes of CU. The primary treatment currently used for CU is the second-generation non-sedating H1-antihistamines (nsAH). However, there are some limitations in current therapies. Based on the latest evidence, this review provides an updated overview of how the gut dysbiosis influences CU development, explores potential therapeutic approaches based on the gut microbiota and summarizes the interaction between gut microbiota and current treatment.

Anti-edematous effects of epinastine, cetirizine and its enantiomers in λ-carrageenan-induced edema in rat hind paw.

Urticaria is induced by the histamine released from mast cells which develops wheals (edema) as a visual feature. In clinical practice, second-generation histamine H1 -receptor blockers are routinely used as the first-line symptomatic treatment for urticaria. Nevertheless, not much research has directly examined the second-generation histamine H1-receptor blockers' ability to reduce edema. In this study, we directly evaluated the anti-edematous activities of three second-generation histamine H1-receptor blockers available in the market (epinastine hydrochloride, cetirizine hydrochloride, and levocetirizine hydrochloride) using a λ-carrageenan-induced footpad edema model. One hour before the induction of edema with 1% λ -carrageenan injection, all second-generation histamine H1 -receptor blockers (5, 10, 50 and 100 mg/kg) were subcutaneously administered to rats. At 0.5 and 3 hours after λ -carrageenan administration, the edema volume was evaluated using a Plethysmometer. Epinastine hydrochloride significantly suppressed the edema growth in a dose-dependent manner. Cetirizine hydrochloride showed a slight anti-edematous effect, while levocetirizine significantly inhibited the development of edema in a dose-dependent manner. On the other hand, dextrocetirizine did not prevent edema from growing. In summary, second-generation histamine H1 -receptor blockers, at least those examined in this study, may be able to reduce the clinical symptoms of urticaria associated with edema. Levocetirizine hydrochloride is also anticipated to have stronger anti-edematous effects than cetirizine hydrochloride because levocetirizine is responsible for cetirizine's anti-edematous activity.

Construction and application of H1R ligand screening materials based on SMA stabilization and his-tag covalent immobilization of membrane proteins.

The histamine H1 receptor (H1R) plays a pivotal role in allergy initiation and undergoes the necessity of devising a high-throughput screening approach centered on H1R to screen novel ligands effectively. This study suggests a method employing styrene maleic acid (SMA) extraction and His-tag covalent bonding to immobilize H1R membrane proteins, minimizing the interference of nonspecific proteins interference while preserving native protein structure and maximizing target exposure. This approach was utilized to develop a novel material for high-throughput ligand screening and implemented in cell membrane chromatography (CMC). An H1R-His-SMALPs/CMC model was established and its chromatographic performance (selectivity, specificity and lifespan) validated, demonstrating a significant enhancement in lifespan compared to previous CMC models. Subsequently, this model facilitated high-throughput screening of H1R ligands in the compound library and preliminary activity verification of potential H1R antagonists. Identification of a novel H1R antagonist laid the foundation for further development in this area.

Cumulative Dose Effects of H1 Antihistamine Use on the Risk of Dementia in Patients With Allergic Rhinitis.

BACKGROUND: H1 antihistamines (AHs), categorized as first-generation antihistamines (FGAs) or second-generation antihistamines (SGAs), possess anticholinergic properties linked to heightened dementia risk. OBJECTIVES: To explore dementia risk in patients with allergic rhinitis using AHs. METHODS: Taiwanese patients with new-onset allergic rhinitis (2011-2017) constituted the study population (677,971 with FGAs or SGAs, 36,081 without AHs). AH use was measured in cumulative defined daily dose (cDDD). Patients were grouped by cDDD (nonuser, <60 cDDD, 60-120 cDDD, and >120 cDDD). A Cox proportional hazard model assessed the AH-dementia association. Sensitivity analysis explored AH effects on dementia risk across subgroups and associations between specific AHs and dementia types. RESULTS: FGAs in patients with allergic rhinitis were associated with elevated dementia risk. At less than 60 cDDD, adjusted hazard ratio (aHR) was 1.13 (95% CI, 1.09-1.17); at 60 to 120 cDDD, aHR was 1.29 (95% CI, 1.21-1.38); and at more than 120 cDDD, aHR was 1.51 (95% CI, 1.42-1.62). SGAs also raised dementia risk. At less than 60 cDDD, aHR was 1.11 (95% CI, 1.05-1.17); at 60 to 120 cDDD, aHR was 1.19 (95% CI, 1.12-1.26); and at more than 120 cDDD, aHR was 1.26 (95% CI, 1.19-1.33). CONCLUSIONS: Patients with allergic rhinitis on FGAs or SGAs face an escalating dementia risk with increasing cumulative dosage. Moreover, FGAs exhibit a higher dementia risk compared with SGAs. Nevertheless, extensive clinical trials are imperative for confirming the association between FGA use, SGA use, and dementia risk.

Suprastin (Chloropyramine) Causes Proarrhythmic Deterioration of Excitation Conduction, Depolarization and Potentiates Adrenergic Automaticity in the Pulmonary Veins Myocardium.

A number of pharmacological drugs have side effects that contribute to the occurrence of atrial fibrillation, the most common type of cardiac rhythm disorders. The clinical use of antihistamines is widespread; however, information regarding their anti- and/or proarrhythmic effects is contradictory. In this work, we studied the effects and mechanisms of the potential proarrhythmic action of the first-generation antihistamine chloropyramine (Suprastin) in the atrial myocardium and pulmonary vein (PV) myocardial tissue. In PV, chloropyramine caused depolarization of the resting potential and led to reduction of excitation wave conduction. These effects are likely due to suppression of the inward rectifier potassium current (IK1). In presence of epinephrine, chloropyramine induced spontaneous automaticity in the PV and could not be suppressed by atrial pacing. Chloropyramine change functional characteristics of PV and contribute to occurrence of atrial fibrillation. It should be noted that chloropyramine does not provoke atrial tachyarrhythmias, but create conditions for their occurrence during physical exercise and sympathetic stimulation.

Diphenhydramine and Migraine Treatment Failure in Pediatric Patients Receiving Prochlorperazine.

OBJECTIVES: The objectives are to determine whether diphenhydramine coadministered with prochlorperazine versus prochlorperazine only is associated with a difference in the risk of migraine treatment failure, as measured by the need for additional therapy, hospitalization rates, and 72-hour return rates, and to compare extrapyramidal adverse effects between groups. METHODS: Retrospective cohort of patients aged 7 to 18 years treated in the emergency department for migraines using prochlorperazine with or without diphenhydramine between 2013 and 2019. Patients were included if they had International Classification of Diseases, Ninth or Tenth Revision, codes for migraine or unspecified headache and were treated with prochlorperazine as part of their initial migraine therapy. Data collected included demographics, medications administered, pain scores, neuroimaging, disposition, return visits, and documentation of extrapyramidal adverse effects. Multivariable logistic regression was used to estimate the association between diphenhydramine coadministration and each of the outcomes. RESULTS: A total of 1683 patients were included. Overall, 13% required additional therapy with a 16.7% admission rate and a 72-hour return rate of 5.3%. There was no association between initial treatment with diphenhydramine and the odds of additional therapy (adjusted odds ratio [aOR], 0.74 [95% confidence interval {CI}, 0.53-1.03]), admission rates (aOR, 1.22 [95% CI, 0.89-1.67]), or return visit rates (aOR, 0.91 [95% CI, 0.55-1.51]). Extrapyramidal adverse effects occurred in 2.4% of patients in the prochlorperazine group and 0% in the prochlorperazine with diphenhydramine group. CONCLUSIONS: There was no association between diphenhydramine coadministration and the need for additional therapy, 72-hour return visit rates or admission rates. Extrapyramidal effects did not occur in patients treated with diphenhydramine.

Update on Urticaria and Angioedema.

Urticaria and angioedema are caused by immunoglobulin E- and non-immunoglobulin E-mediated release of histamine and other inflammatory mediators from mast cells and basophils. Diagnosis is made clinically, and anaphylaxis must be ruled out if urticaria or angioedema is present. A limited nonspecific laboratory workup should be considered unless elements of the history or physical examination suggest specific underlying conditions. The mainstay of treatment is avoidance of triggers when and if triggers are identified. The first-line pharmacotherapy is second-generation H1 antihistamines, which can be titrated to greater than standard doses.

Clinical Characteristics, Investigations and Treatment in Children with Chronic Urticaria: An Observational Study.

Background and Objectives: The guidelines for chronic urticaria in children contain recommendations that are often based on adult studies. The diagnostic pathway has not been standardized and the effectiveness of anti-H1, omalizumab, montelukast, and systemic glucocorticoids is rarely reported in the pediatric population. There is a wide variation in the rate of remission of chronic urticaria between studies. The aim of this study is to enhance our understanding of pediatric chronic urticaria. Materials and Methods: This study enrolled 37 children with chronic urticaria aged from 0 to 18 years. Demographic parameters, medical history, clinical features, laboratory data and treatment information were collected. Children were treated with the recommended dosage of second-generation H1-antihistamines, which was increased by up to twofold. Omalizumab was added for refractory anti-H1 patients. A three-day course with systemic glucocorticoids was administered for severe exacerbations. Montelukast was administered to some children. Results: Wheals without angioedema were common. Chronic urticaria was spontaneous in 32 children (86.48%), inducible in 2 (5.41%), induced by a parasite in 1 and vasculitic in 2. Treatment of the potential causes of chronic urticaria was of no benefit, except for eradication of Dientamoeba fragilis. Chronic urticaria was resolved within three years in 45.9% of cases. Allergic diseases were present in nine children (24.32%) and autoimmune diseases were present in three (8.11%). All children were treated with anti-H1 at the licensed dose or at a higher dose. A partial or complete response to anti-H1 was observed in 29 (78.38%) patients. Montelukast showed no benefit. All children treated with omalizumab responded. Systemic glucocorticoids were successfully used to treat exacerbations. Conclusions: Our findings indicate that laboratory tests should not be routinely performed in children with chronic urticaria without clinical suspicion. However, comorbidities such as thyroid autoimmune disease and coeliac disease are suggested to be monitored over the chronic urticaria course. These clinical conditions could be diagnosed from the diagnostic framework of chronic urticaria. Increasing the dosage of anti-H1 and omalizumab was effective in children resistant to standard treatment but we still need further studies to generate a standard patient-centered treatment.

A Pilot Study of Ketotifen in Patients Aged 8-17 Years with Functional Dyspepsia Associated with Mucosal Eosinophilia.

BACKGROUND AND OBJECTIVE: Mast cells have been implicated in abdominal pain-associated disorders of gut-brain interaction, such as functional dyspepsia. As such, ketotifen, a second-generation antihistamine and mast cell stabilizer, could represent a viable treatment option in these conditions. The primary aim of the current pilot study was to assess clinical response to ketotifen and assess pharmacokinetics in youth with functional dyspepsia. METHODS: We conducted a pilot randomized, double-blind, placebo-controlled, cross-over trial of ketotifen in 11 youth with functional dyspepsia and duodenal mucosal eosinophilia with 4 weeks of active treatment at a dose of 1 mg twice daily. Global clinical response was graded on a 5-point Likert Scale. A single plasma sample was obtained at steady state for pharmacokinetic analysis. RESULTS: Ketotifen was not superior to placebo with regard to global clinical response. Only 18% of patients demonstrated a complete or near-complete clinical response. The estimated half-life was 3.3 h. CONCLUSIONS: While ketotifen was not superior to placebo, this study highlights several important challenges for developing drug trials for youth with chronic abdominal pain. Recommendations are made for designing a larger treatment trial for ketotifen in this patient group. CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov: NCT02484248.

Blockade of histamine receptor H1 augments immune checkpoint therapy by enhancing MHC-I expression in pancreatic cancer cells.

BACKGROUND: Although immune checkpoint blockade (ICB) therapy has proven to be extremely effective at managing certain cancers, its efficacy in treating pancreatic ductal adenocarcinoma (PDAC) has been limited. Therefore, enhancing the effect of ICB could improve the prognosis of PDAC. In this study, we focused on the histamine receptor H1 (HRH1) and investigated its impact on ICB therapy for PDAC. METHODS: We assessed HRH1 expression in pancreatic cancer cell (PCC) specimens from PDAC patients through public data analysis and immunohistochemical (IHC) staining. The impact of HRH1 in PCCs was evaluated using HRH1 antagonists and small hairpin RNA (shRNA). Techniques including Western blot, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-PCR), and microarray analyses were performed to identify the relationships between HRH1 and major histocompatibility complex class I (MHC-I) expression in cancer cells. We combined HRH1 antagonism or knockdown with anti-programmed death receptor 1 (αPD-1) therapy in orthotopic models, employing IHC, immunofluorescence, and hematoxylin and eosin staining for assessment. RESULTS: HRH1 expression in cancer cells was negatively correlated with HLA-ABC expression, CD8+ T cells, and cytotoxic CD8+ T cells. Our findings indicate that HRH1 blockade upregulates MHC-I expression in PCCs via cholesterol biosynthesis signaling. In the orthotopic model, the combined inhibition of HRH1 and αPD-1 blockade enhanced cytotoxic CD8+ T cell penetration and efficacy, overcoming resistance to ICB therapy. CONCLUSIONS: HRH1 plays an immunosuppressive role in cancer cells. Consequently, HRH1 intervention may be a promising method to amplify the responsiveness of PDAC to immunotherapy.

Advances in clinical application of H1 antihistamines in the treatment of skin diseases. / H1æŠ—ç»„èƒºè¯åœ¨çš®è‚¤ç— æ²»ç–—ä¸­çš„ä¸´åºŠåº”ç”¨è¿›å±•.

Histamine receptors are classified into 4 types: H1, H2, H3, and H4, each mediating distinct physiological effects and possessing its corresponding antagonistshat that can be used for the prevention and treatment of various diseases. Among them, H1 antihistamines are the fundamental medications in dermatology and are widely used in many diseases such as urticaria and atopic dermatitis. In recent years, with the emergence of novel antihistamines and the discovery of new potential indications for traditional H1 antihistamines, the clinical application of antihistamines is facing new challenges. Further investigation of the novel mechanism for H1 antihistamines, the use of multiple doses of common drugs and potential indications will furnish vital insights for practical clinical application.

The antiglycation potential of H1 receptor antagonists - in vitro studies in bovine serum albumin model and in silico molecular docking analyses.

The H1 receptor belongs to the family of rhodopsin-like G-protein-coupled receptors activated by the biogenic amine histamine. H1 receptor antagonists are widely used in the treatment of allergies. However, these drugs could have a much broader spectrum of activity, including hypoglycemic effects, which can broaden the spectrum of their use. The aim of the study was to evaluate the antiglycation potential of twelve H1 receptor antagonists (diphenhydramine, antazoline, promethazine, ketotifen, clemastine, pheniramine, cetirizine, levocetirizine, bilastine, fexofenadine, desloratadine, and loratadine). Bovine serum albumin (BSA) was glycated with sugars (glucose, fructose, galactose, and ribose) and aldehydes (glyoxal and methylglyoxal) in the presence of H1 blockers. The tested substances did not induce a significant decrease in the content of albumin glycation end-products, and the inhibition rate of glycoxidation was not influenced by the chemical structure or generation of H1 blockers. None of the tested H1 receptor antagonists exhibited strong antiglycation activity. Antiglycemic potential of H1 blockers could be attributed to their antioxidant and anti-inflammatory activity, as well as their effects on carbohydrate metabolism/metabolic balance at the systemic level.

Novel HPTLC method for simultaneous estimation from ternary mixture of chlorpheniramine maleate, dextromethorphan hydrobromide and phenylephrine hydrochloride in syrup formulations.

OBJECTIVES: A synergic antihistamine, cough suppressant, and decongestant combination of chlorpheniramine, dextromethorphan, and phenylephrine is used to treat acute respiratory infections caused by seasonal viruses. The effective qualitative and quantitative methods require the simultaneous measurement of a ternary combination in the pharmaceutical syrup dosage form. Therefore, a new, simple, fast and robust high performance thin layer chromatographic (HPTLC) method has been developed and validated for chlorpheniramine maleate (CPM), dextromethorphan hydrobromide (DEXO) and phenylephrine hydrochloride (PE). MATERIAL AND METHODS: The chromatographic separation was carried out on precoated aluminium plates with silica gel 60 F254 as the stationary phase. Mobile phase used was chloroform: methanol: ammonia (2.5:7.5:0.3, v/v/v) for proper separation. The detection was carried out at 270nm wavelength in absorbance mode. Developed method was validated as per International Council for Harmonization (ICH) Q2 (R1) guideline. RESULTS: The linearity range is 400 to 1400ng/band for CPM, 3000 to 11500ng/band for DEXO and 1000 to 3500ng/band for PE with correlation coefficient ≥ 0.995. The consistent lower values of relative standard deviation (RSD, %) for precision and robustness study indicate the method reliability. The percent recovery ranged from 97.82 to 102.03% indicates the good accuracy of the method. CONCLUSION: The proposed method was complying for the analytical method validation parameters suggested by the ICH Q2 (R1) guideline. The method was found to be simple, rapid and reliable for the simultaneous estimation of CPM, DEXO and PE from its pharmaceutical syrup dosage form. The method was successfully applied to quantify these analytes from the several pharmaceutical syrup dosage form.

Allergic Rhinitis: A Review.

Importance: Allergic rhinitis affects an estimated 15% of the US population (approximately 50 million individuals) and is associated with the presence of asthma, eczema, chronic or recurrent sinusitis, cough, and both tension and migraine headaches. Observations: Allergic rhinitis occurs when disruption of the epithelial barrier allows allergens to penetrate the mucosal epithelium of nasal passages, inducing a T-helper type 2 inflammatory response and production of allergen-specific IgE. Allergic rhinitis typically presents with symptoms of nasal congestion, rhinorrhea, postnasal drainage, sneezing, and itching of the eyes, nose, and throat. In an international study, the most common symptoms of allergic rhinitis were rhinorrhea (90.38%) and nasal congestion (94.23%). Patients with nonallergic rhinitis present primarily with nasal congestion and postnasal drainage frequently associated with sinus pressure, ear plugging, muffled sounds and pain, and eustachian tube dysfunction that is less responsive to nasal corticosteroids. Patients with seasonal allergic rhinitis typically have physical examination findings of edematous and pale turbinates. Patients with perennial allergic rhinitis typically have erythematous and inflamed turbinates with serous secretions that appear similar to other forms of chronic rhinitis at physical examination. Patients with nonallergic rhinitis have negative test results for specific IgE aeroallergens. Intermittent allergic rhinitis is defined as symptoms occurring less than 4 consecutive days/week or less than 4 consecutive weeks/year. Persistent allergic rhinitis is defined as symptoms occurring more often than 4 consecutive days/week and for more than 4 consecutive weeks/year. Patients with allergic rhinitis should avoid inciting allergens. In addition, first-line treatment for mild intermittent or mild persistent allergic rhinitis may include a second-generation H1 antihistamine (eg, cetirizine, fexofenadine, desloratadine, loratadine) or an intranasal antihistamine (eg, azelastine, olopatadine), whereas patients with persistent moderate to severe allergic rhinitis should be treated initially with an intranasal corticosteroid (eg, fluticasone, triamcinolone, budesonide, mometasone) either alone or in combination with an intranasal antihistamine. In contrast, first-line therapy for patients with nonallergic rhinitis consists of an intranasal antihistamine as monotherapy or in combination with an intranasal corticosteroid. Conclusions and Relevance: Allergic rhinitis is associated with symptoms of nasal congestion, sneezing, and itching of the eyes, nose, and throat. Patients with allergic rhinitis should be instructed to avoid inciting allergens. Therapies include second-generation H1 antihistamines (eg, cetirizine, fexofenadine, desloratadine, loratadine), intranasal antihistamines (eg, azelastine, olopatadine), and intranasal corticosteroids (eg, fluticasone, triamcinolone, budesonide, mometasone) and should be selected based on the severity and frequency of symptoms and patient preference.

UCOMB-real life data: treatment strategies for chronic urticaria patients with comorbidities.

BACKGROUND: There is a lack of real-life safety data on treatment options for chronic urticaria in the presence of comedication and comorbidities. METHODS: We present a single-center UCARE pilot study of 212 outpatients with chronic urticaria. Patients were divided into three groups according to different CU therapies according to international guidelines. RESULTS: Of 212 patients, 108 (mean age 48.9 years, 71.3% female) had 59 comorbidities, including cardiovascular, autoimmune and malignant diseases. Patients were followed for a mean of 24.6 months (SD ± 21.3). Urticaria therapies were divided into three groups: A: 105 (97.2%) with omalizumab and 2nd generation antihistamines), B: 16 patients (14.8%): dual therapy with antihistamines and cyclosporine in 10 (9.3%), montelukast in five (4. 6%), dapsone in four (3.7%), hydroxychloroquine in one patient (0.9%), C: 12 (11.1%) patients received a third drug for 4.9 months (SD ± 3.2) and one quadruple therapy (2.1 months). 10 out of 12 (83.3%) patients received montelukast, two (16.7%) cyclosporine, two (16.7%) dapsone and one (8.3%) hydroxychloroquine as a third drug for chronic urticaria. CONCLUSIONS: Combining treatment modalities for chronic urticaria and comorbidities are available and feasible with a good safety profile.

[Approved therapies and their effects on the main symptoms of urticaria : When symptom control of itchy wheals is not adequate-does updosing help?] / Zugelassene Therapien und ihre Wirkung auf die Leitsymptome der Urtikaria : Hilfreiche Therapieoptionen, wenn juckende Quaddeln nicht weichen ­ Viel hilft viel?

International guidelines for the treatment of chronic spontaneous urticaria support the updosing of second-generation antihistamines to four times of the approved dose when adequate symptom control cannot be achieved with the standard dosage. However, this recommendation is primarily based on expert opinions, and there is a lack of large, well-designed, double-blind clinical trials. Most the existing trials provide insufficient data, and due to the heterogeneity of the conducted trials on antihistamine effects (definition of control, design, quality, lack of an active comparator, no placebo arm, small sample size, outcomes) and their short duration, comparative analysis is challenging. However, it can be concluded that the use of modern second-generation antihistamines is both effective and safe based on the available data and our own long-term experiences in the specialized outpatient clinic of a university dermatology department, even though increased dosages (up to fourfold as per the current international guidelines) may be necessary for symptom control. Another therapeutic option for refractory symptoms in chronic spontaneous urticaria is subcutaneous administration of omalizumab at a dosage of 300 mg at 4­week intervals as a very safe and effective treatment.

Dimetindene-Is the minimum toxic dose for children too strict?

Dimetindene is a sedating antihistamine indicated for the symptomatic treatment of allergic conditions. Dimetindene is marketed among others under the trade name Fenistil (oral solution). Toxicity data are limited, and there is no consensus on the dose at which children require hospitalization. Objective is to determine the potentially toxic dose in children. Data in children with age up to 15 years were obtained from hospital discharge reports. Of 139 paediatric hospital discharge reports, 23 cases (16.5%) were excluded because of uncertain ingestion. In 116 children (46 boys and 70 girls, mean age 2 years and 9 months ± 1 year and 1 month), the majority of children developed no symptoms (87 children, 75%, mean age 3 years±1 year) and the remaining 29 children (25%, mean age 2 years and 11 months ± 1 year and 3 months) developed only mild and spontaneously resolving symptoms of poisoning after a dose of 0.82 ± 0.32 mg/kg b.w. (range 0.26-1.82 mg/kg). In 98% of all cases, hospitalized children were observed for a maximum 24 h, and their condition did not require specific treatment. In conclusion, the prognosis for accidental dimetindene poisoning in children appears to be good and the minimum toxic dose has been determined to be 0.5 mg/kg b.w.

Shedding light on dermographism: a narrative review.

Dermographism is a common subtype of chronic urticaria. It generally manifests as a linear wheal after scratching or friction, with or without angioedema. The pathophysiology is not clear, but currently, we believe that the stimulation of the skin by mechanical stress leads to the activation of mast cells, which provoke the release of histamine and pro-inflammatory mediators, ultimately forming wheal along the stressed area. The gold standard for diagnosis is a medical history and provocation test or dermatographic test. As one of the subtypes of chronic urticaria, the Urticaria Control Test (UCT), Chronic Urticaria Quality of Life questionnaire (CU-Q2oL), and Dermatology Life Quality Index (DLQI) are also effective tools for evaluating disease control in dermographism patients. In addition to avoiding triggers, nonsedating H1 antihistamines are the first-line medications recommended by EAACI and other guidelines; for those who do not respond to standard doses, the recommended dosage can be increased up to 4 times. When necessary, the off-label use of omalizumab can be considered, and some drugs with potential therapeutic effects are still being explored. However, there is still a lack of biomarkers for predicting disease severity, efficacy, and prognosis. Here, we review what we know about dermographism and some points that need exploration in the future.