Allergy Symptoms Research Articles

Effect of occupational exposure to ADCA on the incidence of allergic respiratory reactions - a literature review

1,1'-azodi(formamide) (ADCA) is widely used as a blowing agent, a chemical substance designed to induce foaming processes. In Poland, ADCA is manufactured by a company specializing in the production of polyethylene foam bags and laminates used in various industries including home appliances, electronics, construction, furniture, automotive, and sports and leisure. The mechanism of action of ADCA involves thermal decomposition, resulting in nitrogen, carbon monoxide, as well as ammonia and carbon dioxide as the main gaseous decomposition products. These penetrate the polymer matrix, contributing to expansion and foaming properties. Most studies evaluating the relationship between occupational exposure and the development of allergic respiratory diseases focus on workers involved in ADCA production or its use as a blowing agent in plastics. The objective is to assess the respiratory sensitizing effects of ADCA in humans due to occupational exposure, based on literature data. The presented data confirm that long-term occupational exposure to ADCA can lead to persistent bronchial hyperreactivity symptoms in workers. 1,1'-azodi(formamide) can induce occupational asthma, with initial symptoms including nasal congestion, conjunctivitis, wheezing, and cough. Subsequently, symptoms such as chest tightness, dyspnea, and nocturnal cough attacks may appear, with a latency period of several years observed before symptom onset. In some cases, symptom progression was noted with continued ADCA exposure, while in others, exposure was discontinued after initial symptoms, preventing observation of symptom exacerbation. Prior exposure to allergens, such as working in bakeries, appears to accelerate symptom onset. Improvement in allergy symptoms has been noted during weekend breaks from work. There is no safe concentration identified for ADCA that would not result in adverse health effects for workers. A concentration of 0.036 mg/m3 is considered the lowest observed adverse effect concentration, causing critical reduction in lung spirometric parameters. Med Pr Work Health Saf. 2024;75(5).

Allergy to aquatic biological resources as food

The review reveals the problem of allergies to fish and other highly allergenic foods. First of all, the products obtained from aquatic organisms are considered. The world production of fish of various species is discussed with the presentation of FAO statistics for recent years in this article. The role of aquaculture in the production of fish, shellfish and crustaceans is considered. In particular, the trends of fishing in the Black Sea and the growth of aquaculture production in Russia are analyzed. Generalized data indicate an increase in the importance of aquatic biological resources (ABR) in a balanced human diet. The study demonstrates the role of parvalbumin in the mechanism of development of allergies to products from ABR. Examples of other allergenic proteins that contain epitopes that trigger allergic reactions in the human body are given. The mechanism of these reactions is briefly described. Attention is drawn to cross-allergic reactions. Anthropogenic factors that can exacerbate allergies to fish products are discussed. These are pesticides, herbicides, antibiotics, detergent components, changes in chemical composition, and food storage conditions. Pseudoallergens with the ability to cause allergic reactions are also mentioned. Allergy symptoms can range from skin rashes and itching to respiratory problems and anaphylaxis. Treatment of fish allergy is similar to treatment for allergies to other foods. It includes the use of antihistamines, corticosteroids and sorbents. Heredity plays a major role in the development of allergic reactions. It is important to pay attention to the purity and quality of products, cooking methods, and also follow a diet. Due to the potentially higher cumulative toxicity of freshwater species, it is recommended that marine fish be preferred.

A Mixture of Four Probiotic Strains (Probiatop®) Mitigates Food Allergy to Ovalbumin in Mice.

Food allergy is a pathological condition caused by a disruption of oral tolerance. This condition leads to a pro-inflammatory environment that culminates in symptoms that varies from abdominal pain to anaphylaxis and death. The gold standard treatment consists of removing the food that triggers the allergy from diet. However, this conduct can cause nutritional impairment and social restrictions. Therefore, the need for new treatment strategies is notorious. In this context, probiotics are investigated due to their immunomodulatory mechanisms. Therefore, the objective of the present work is to investigate the probiotic potential of a mixture of four probiotic strains (Probiatop®) in an in vivo model of food allergy to ovalbumin (OVA). Our results demonstrated that oral administration of Probiatop® attenuated weight loss and diminished significantly anti-OVA IgE and IgG1 levels. Furthermore, it mitigated proximal jejunum injury, neutrophil recruitment and local IL17 levels. In addition, the probiotic mixture modulated positively the gut microbiota composition by decreasing the levels and frequency of Staphylococcus and yeast. In summary, our data suggest that Probiatop® has the potential to alleviate important symptoms of IgE-mediated food allergy, suggesting its probiotic potential as an adjuvant in the treatment of ovalbumin food allergy.

Preventing Overrides of Severe Drug Allergy Alerts Initiative: an Implemented System Upgrade

Administering medications to patients with documented drug hypersensitivity reactions (DHR) poses a significant risk for adverse events, ranging from mild reactions to life-threatening incidents. Electronic healthcare systems have revolutionized the modern clinical decision-making process, with built in warnings. However, as these alerts become a routine part of healthcare provider’s workflow, alert fatigue becomes a challenge. This study was conducted within the Ministry of National Guard Health Affairs (MNGHA), a government healthcare system in Saudi Arabia. A taskforce of experts was formed to develop an electronic path that would prevent unintentional overrides of severe drug allergy alerts. The system underwent rigorous testing, and monitoring parameters were established. We outline the implementation of a system upgrade designed to trigger an alternative interruption in the computerized physician order entry (CPOE) process, distinct from the regular allergy pop-up alerts. The alternate path is activated upon a CPOE with a drug-to-drug match and a documented severe drug allergy symptom, necessitating co-signature form another prescriber before proceeding. The adopted upgrade is a proactive approach to enhance medication safety in electronic healthcare systems, ensuring that serious allergy-related warnings are not overridden, ultimately enhancing patient safety. Further monitoring will confirm the safety and effectiveness of this measure. This study provides a model for institutions seeking to prevent allergy-related harm within their patient population.

Management of a liver hydatid cyst patient who fistulized the diaphragm and subsequently presented with thorax rupture: a case report

Hydatid cysts, caused by Echinococcus species, are zoonotic diseases frequently observed in endemic regions worldwide, including Turkey. It is most commonly localized in the liver, followed by the lungs. Anaphylaxis and peritonitis, which develop after cyst rupture, are the most significant complications observed in these patients. Early diagnosis and prompt surgical intervention are extremely important. This study presented an extremely rare case of a hepatic hydatid cyst ruptured into the thorax, which may have high morbidity and mortality. A 24-year-old male patient presented to our emergency department with cough, dyspnea, fever, and allergy symptoms. He had a history of hepatic hydatid cyst surgery 5 years ago. Physical examination revealed urticarial lesions on the skin. The body temperature was 39 °C, and the pulse rate was 120 beats/min. Laboratory tests revealed leukocytosis and elevated C-reactive protein. Contrast-enhanced thoracic and abdominal computed tomography was performed. Diagnostic tests revealed that the patient had a ruptured hepatic hydatid cyst in the right thoracic cavity; hence, he was scheduled for emergency surgery. Laparotomy was performed via a right subcostal incision, and the ruptured cyst was located. It was understood that this cyst had fistulized into the diaphragm during a chronic process and subsequently ruptured acutely into the thorax. Partial cystectomy was performed for a ruptured liver cyst. The diaphragm was repaired, and catheters were placed in the thorax and abdomen for drainage. There were no other postoperative complications. Rupture of hydatid cyst disease is frequently observed in endemic regions. The rupture of a hepatic hydatid cyst into the thorax is an extremely rare event. In patients presenting with pulmonary symptoms who have a history of hepatic hydatid cyst surgery, the abdomen should always be thoroughly evaluated, and emergency surgery should be performed if required.

Retinoic Acid (RA): A Critical Immunoregulatory Molecule in Asthma and Allergies.

Asthma and allergies are chronic inflammatory disorders that are triggered owing to aberrant responses of the immune system against typically innocent environmental substances. Retinoic acid (RA) represents a biologically active metabolite of vitamin A (VA) and high-affinity ligand for RA receptor (RAR) that is implicated in a wide variety of biological processes, including cell proliferation, differentiation, apoptosis, organogenesis, reproduction, and immune responses. In the immune system, RA contributes to the induction of regulatory T (Treg) cells, adhesion molecules required for homing of B and T cells in the gut, and tolerance. Noteworthy, RA has a pivotal role in maintaining the balance of Th17-Treg cells and is also indispensable for appropriate responses of T helper (Th) cells. This mini-review article intends to expose the immune functions of RA, with an emphasis on the enzymatic pathways converting VA into RA and its receptor-dependent actions in asthma and allergies. Recent findings have depicted that RA levels are reduced in asthma and allergies and that treatment with RA alleviates allergy symptoms and airway inflammation. RA also modulates allergic airway disorders by inhibiting Th2/Th17 response and increasing Treg cells. Therefore, RA could be considered a novel and promising therapeutic agent to be studied and used for treating these diseases.

Evaluating the Efficacy and Safety of Cymbopogon Schoenanthus Syrup for Asthma and Allergies: A Two-Decade Clinical Study

Asthma and allergies are prevalent respiratory conditions affecting millions worldwide, often necessitating long-term management and treatment. Synthetic medications, while effective, may pose risks and adverse effects, prompting exploration into natural alternatives. This study investigates the efficacy and safety of a botanical syrup supplement derived from Cymbopogon Schoenanthus subsp. proximus, known as “Binj” or “Abba” in the United Arab Emirates (UAE), for the management of asthma and allergies. Through collaborative efforts with reputable laboratories and universities, the botanical syrup’s therapeutic potential was rigorously evaluated, encompassing phytochemical analysis, biological testing, and extensive clinical trials spanning two decades. Results demonstrate notable improvements in lung function and skin health among patients with asthma and allergies, evidenced by enhanced vital capacity, forced vital capacity, and visible reduction in skin allergy symptoms. Furthermore, safety assessments indicate a favorable profile, with minimal adverse events reported. The recognition of the botanical syrup by the UAE Ministry of Health and international pharmaceutical companies underscores its significance and potential for widespread application. This discovery represents a promising advancement in natural medicine, offering a safe and effective alternative for individuals seeking holistic respiratory wellness. Future research should focus on large-scale clinical trials and long-term safety studies to further elucidate its therapeutic benefits and optimize clinical outcomes.

Divergent sensory pathways of sneezing and coughing

Sneezing and coughing are primary symptoms of many respiratory viral infections and allergies. It is generally assumed that sneezing and coughing involve common sensory receptors and molecular neurotransmission mechanisms. Here, we show that the nasal mucosa is innervated by several discrete populations of sensory neurons, but only one population (MrgprC11+MrgprA3-) mediates sneezing responses to a multitude of nasal irritants, allergens, and viruses. Although this population also innervates the trachea, it does not mediate coughing, as revealed by our newly established cough model. Instead, a distinct sensory population (somatostatin [SST+]) mediates coughing but not sneezing, unraveling an unforeseen sensory difference between sneezing and coughing. At the circuit level, sneeze and cough signals are transmitted and modulated by divergent neuropathways. Together, our study reveals the difference in sensory receptors and neurotransmission/modulation mechanisms between sneezing and coughing, offering neuronal drug targets for symptom management in respiratory viral infections and allergies.

Role of Probiotics and Prebiotics in Human Health: A Review

Probiotics and prebiotics are essential components in maintaining and enhancing human health, primarily through their beneficial effects on gut microbiota. Probiotics, which are live microorganisms, and prebiotics, which are non-digestible food components, work synergistically to improve digestive health, enhance immune function, and support metabolic health. The historical evolution of probiotics and prebiotics has demonstrated their wide-ranging health benefits, from preventing gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) to managing metabolic disorders like obesity and type 2 diabetes. Clinical applications highlight their role in reducing antibiotic-associated diarrhea, enhancing insulin sensitivity, and mitigating symptoms of allergies and autoimmune diseases. However, the field faces significant challenges, including the need for standardization and quality control, addressing individual variability in response, and ensuring safety and efficacy. The lack of uniform regulatory oversight further complicates the assurance of product reliability and effectiveness. Despite these challenges, emerging trends and innovations, such as next-generation probiotics and prebiotics, personalized nutrition based on microbiome profiles, and advances in biotechnology and bioinformatics, offer promising solutions. These advancements are poised to enhance the specificity and effectiveness of probiotic and prebiotic interventions. For example, genetically engineered probiotics and novel prebiotics derived from non-traditional sources are being explored for their unique health benefits. Personalized approaches can optimize dietary recommendations and supplement formulations based on individual gut microbiome compositions. Future research directions should focus on mechanistic studies to elucidate the specific pathways through which probiotics and prebiotics exert their effects, conducting robust and diverse clinical trials, and developing new strains and compounds from diverse sources. Regulatory frameworks need to be established to ensure the safety, efficacy, and quality of these products. By addressing these challenges and leveraging innovative approaches, probiotics and prebiotics can be optimized to provide personalized and effective health solutions, significantly impacting public health. Integrating these functional foods into daily dietary practices holds the potential for a new era of preventive and therapeutic nutrition, enhancing overall health and well-being.

The synergies effect of 3′-sialyllactose and 2′-fucosyllactose on the attenuation of food allergy symptoms in a mouse model

The synergies effect of 3′-sialyllactose and 2′-fucosyllactose on the attenuation of food allergy symptoms in a mouse model

Astragalus membranaceus, Nigella sativa, and Perilla frutescens as Immunomodulators-Molecular Mechanisms and Clinical Effectiveness in Allergic Diseases.

Plants are the source of numerous remedies in modern medicine, and some of them have been studied due to their potential immunomodulatory activity. Astragalus membranaceus Fisch. ex Bunge (A. membranaceus), Nigella sativa L. (N. sativa), and Perilla frutescens (L.) Britton (P. frutescens) are plant species used in traditional medicine for the treatment of various diseases. Their potential to act as immunomodulatory, anti-inflammatory, and anti-allergic agents makes them interesting for investigating their clinical potential in alleviating the symptoms of allergic diseases. Allergy affects a large number of people; according to some sources more than 30% of the world population suffer from some type of allergic reaction, with pollen allergy as the most common type. Treatment is usually pharmacological and may not be completely effective or have side effects. Thus, we are seeking traditional medicine, mostly medicinal plants, with promising potential for alleviating allergy symptoms. A literature overview was conducted employing databases such as Scopus, PubMed, Web of Science, Springer, and Google Scholar. This manuscript summarizes recent in vivo preclinical and clinical studies on three species with immunomodulatory activity, provides a comparison of their anti-allergic effects, and underlines the potential of their application in clinical practice. The obtained results confirmed their efficacy in the in vivo and clinical studies, but also emphasize the problem of phytochemical characterization of the species and difference between tested doses. More clinical trials with standardized protocols (defined active molecules, dosage, side effects) are required to obtain safe and effective herbal drugs.

In-home air purifiers and allergy symptoms: A randomized cross-over trial in older adults

In-home air purifiers and allergy symptoms: A randomized cross-over trial in older adults

Maternal exposure to pyrethroid insecticides during pregnancy and respiratory allergy symptoms among South African children

Maternal exposure to pyrethroid insecticides during pregnancy and respiratory allergy symptoms among South African children

Pollen effects in a changing climate: Ragweed pollen exposure and sleepiness in immunotherapy patients of a Southeastern Michigan allergy clinic.

Allergic rhino-conjunctivitis (AR) is a globally relevant health disorder characterized by sneezing, rhinorrhea and sleep disturbance. Ragweed (Ambrosia artemisiifolia) is a plant common to North America and an important allergen. Coarse methods of measuring airborne pollen counts are used to predict seasonal allergy symptoms. This research used a longitudinal study design with a novel, model-based raster of predicted pollen counts to test associations with self-reported symptoms of AR collected from patients receiving immunotherapy for pollen allergies at an allergy clinic. Researchers visited a clinic six times over three weeks. Immunotherapy patients were asked to fill out a brief intake survey on allergic and symptomatic profiles, daytime sleepiness, housing quality, and demographics. Participants responded to a daily, emailed survey on sleepiness and asthma symptoms for 21 days. Using the date and location of responses, ragweed pollen counts were extracted from a prognostic, model based raster (25km pixels). Lag associations of pollen counts with sleepiness were tested using a logistic regression model , adjusted for housing and demographic characteristics, in a distributed lag non-linear model (DLNM) framework. 49 people participated in the study. 26 (52%) were female. The mean age was 37.9 years. Asthma/allergy symptoms were not associated with ragweed pollen but sleepiness was highest two days after exposure (Estimate: 0.33 [0.04,0.62]). Subjects traveled widely during the study period. Intense exposures to ragweed pollen may be associated with daytime sleepiness within small exposure windows. Model-based predicted pollen counts could be used to study health impacts of pollen in people with disease severe enough to receive immunotherapy. Daytime sleepiness can affect productivity and injury risk, and pollen season length and allergenicity may be increasing with climate change. Thus our results may have important implications for population health.

Application of Innovative Digital Medical Technologies of Bioquantum Medicine and Therapy in Elimination of Allergy Symptoms

In recent years, there has been an increasing integration of alternative medical technologies, particularly those involving digital medical technologies based on quantum and bioquantum medicine, frequency and wave therapy, and bioquantum therapy, for treating COVID-19, post-COVID, and long-COVID conditions as outlined in ICD-11. This study aimed to experimentally evaluate the latest digital medical technologies, specifically focusing on bioquantum therapy, for allergy treatment. A comprehensive review of existing literature on the application of bioquantum medicine in allergy therapy was conducted. The findings confirm that bioquantum therapy is an effective treatment option for mild to moderate allergies, significantly enhancing symptoms and overall quality of life. BICOM devices are recommended for managing mild to moderate allergies and associated complications. Furthermore, the study highlights that BICOM therapy is not only effective but also safe, with no serious adverse effects observed throughout the year-long study period. Given these promising results, it is recommended that healthcare professionals pursue specialized training, including master classes and continuous professional development in bioquantum medicine and therapy. Obtaining the necessary licenses and permits to work with BICOM devices is essential for ensuring the safe and effective application of this innovative treatment method. As the field continues to evolve, staying updated on the latest advancements in bioquantum medicine will be crucial for medical practitioners.

The Cow's Milk-Related Symptom Score (CoMiSSTM) in Presumed Healthy Egyptian Infants.

The Cow's Milk-Related Symptom Score (CoMiSS) was created as an awareness tool for cow's milk-related symptoms. After different trials, a score of ≥10 was selected to raise awareness. The CoMiSS in healthy infants needs to be determined because the score does not return to 0 during a diagnostic elimination diet. This study aims to establish normal values in healthy Egyptian infants. In this prospective cross-sectional study, pediatricians determined the CoMiSS in healthy infants ≤ 12 months. Infants seeking medical help due to cow's milk allergy (CMA) symptoms and infants with any known or suspected diseases, preterm delivery, medication, or food supplements were excluded. A total of 808 infants were included with a median (Q1; Q3) age of 7 (3;10) months (50.7% boys). The median (Q1; Q3) CoMiSS was 5 (5;6). The 95th percentile was 7. There was no significant difference in the median CoMiSS according to gender (p = 0.621) or due to breastfeeding exclusively (p = 0.603). A significant difference was seen in the CoMiSS according to age, although all the age categories had a median CoMiSS of 5. This study revealed the median CoMiSS is 5 in presumed healthy Egyptian infants aged 0-12 months. The CoMiSS was not dependent on feeding. The determination of the CoMiSS in healthy infants allows for the determination of a cut-off under which CMA is unlikely, and a cut-off to raise awareness of CMA, thereby preventing under- and overdiagnosis. Since the median CoMiSS was not different in European infants, the outcome suggests that the CoMiSS may be a reliable awareness tool for CMA independent of ethnicity. However, additional studies are needed to confirm the previous hypothesis.

A randomized, double-blind, placebo-controlled study to evaluate the benefits of a standardized Nigella sativa oil containing 5% thymoquinone in reducing the symptoms of seasonal allergy.

Allergic rhinitis (AR) or seasonal allergy characterized by sneezing, nasal congestion, nasal itching, and nasal discharge, triggered by immune reactions to environmental allergens. Present day customers also monitor the personal improvements in the area of Evidence-Based natural medicines/supplements. A randomized, double-blind, placebo-controlled study was conducted on 65 participants aged 18 to 60 years having 2 or more allergic symptoms like sneezing, rhinorrhoea, nasal obstruction, and nasal itching for a cumulative period greater than 1 hour per day. The study participants received a capsule of NSO (250 mg) with 2.5 mg piperine (BioPerine) as a bioavailability enhancer or a placebo, twice a day, after food for 15 days. The primary objectives were evaluated by mean change in Total Nasal Symptom Score and the duration of AR symptoms per day from baseline to Day 15. Secondary endpoints were changes in Total Ocular Symptoms Score, AR symptom frequency and severity, serum Immunoglobulin E levels, and Patient Global Impression of Change scale. Adverse events were monitored throughout the study. Sixty-five patients were enrolled and all of them completed the study, N = 33 in NSO and N = 32 in placebo. A significant reduction in Total Nasal Symptom Score and Total Ocular Symptoms Score was observed in the NSO group compared to the placebo, highlighting the potential of NSO in alleviating AR symptoms. The episodes of AR symptoms per day and the frequency of symptoms in 24 hours reduced significantly in 15 days in both groups, but the extent of improvement was significantly higher in NSO compared to placebo. Improvement in Patient Global Impression of Change was also significantly better in NSO compared to the placebo. Serum Immunoglobulin E levels decreased in NSO but were not significantly different from placebo. No clinically significant changes were observed in vital signs, liver and renal function, lipid profile, hematology, fasting blood sugar, or urine analysis at the end of the study. The result of the study demonstrates that NSO 250 mg with 2.5 mg piperine is an effective and well-tolerated supplement for the management of AR symptoms.

Uronium peptide coupling agents: Another case of occupational airborne allergic sensitization induced by HBTU.

Uronium peptide coupling agents (HBTU, HATU, and HCTU) create a special hazard as they are immune sensitizers. Few reported cases are mentioned in the literature; despite that, it is important to raise the awareness on the subject and to highlight the risk and potential symptoms that could occur to those who directly work in contact with uronium peptide coupling agents, as well as to the safety deputies in the universities and industries. Based on a personal experience, the health impact of laboratory exposure to HBTU is described, and the insights gained from the experience are developed. A skin irritation reaction and allergy symptoms induced by HBTU exposure are shown here as well as the rate of worsening of symptoms since the first allergic reaction. Recommendations for handling coupling agents more safely in the research laboratory will also be given, and a casuistry of the matter to help other lab-users to recognize, assess, minimize, prepare for emergencies (RAMP) process.

Assessing allergy risk from ornamental trees in a city: Integrating open access remote sensing data with pollen measurements

Platanus sp. pl. (plane trees) are common ornamental tree in Poland that produces a large amount of wind-transported pollen, which contains proteins that induce allergy symptoms. Allergy sufferers can limit their contact with pollen by avoiding places with high pollen concentrations, which are restricted mainly to areas close to plane trees. Their location is thus important, but creating a detailed street tree inventory is expensive and time-consuming. However, high-resolution remote sensing data provide an opportunity to detect the location of specific plants. But acquiring high-resolution spatial data of good quality also incurs costs and requires regular updates. Therefore, this study explored the potential of using open access remote sensing data to detect plane trees in the highly urbanized environment of Poznań (western Poland). Airborne light detection and ranging (LiDAR) was used to detect training treetops, which were subsequently marked as young plane trees, mature plane trees, other trees or artefacts. Spectral and spatial variables were extracted from circular buffers (r = 1 m) around the treetops to minimize the influence of shadows and crown overlap. A random forest machine learning algorithm was applied to assess the importance of variables and classify the treetops within a radius of 6.2 km around the functioning pollen monitoring station. The model performed well during 10-fold cross-validation (overall accuracy ≈ 92%). The predicted Platanus sp. pl. locations, aggregated according to 16 wind directions, were significantly correlated with the hourly pollen concentrations. Based on the correlation values, we established a threshold of prediction confidence, which allowed us to reduce the fraction of false-positive predictions. We proposed the spatially continuous index of airborne pollen exposure probability, which can be useful for allergy sufferers. The results showed that open-access geodata in Poland can be applied to recognize major local sources of plane pollen.

In utero exposure to antihistamines and risk of hepatocellular carcinoma in a multigenerational cohort.

Growing evidence suggests that liver disease originates in early life. Antihistamines cross the placenta and are frequently prescribed to pregnant women to treat nausea and vomiting, as well as allergy and asthma symptoms. Exposure to antihistamines in utero may impact the developing liver by reprogramming or inducing epigenetic changes in fetal hepatocytes. We examined in utero exposure to antihistamines and the risk of HCC in the Child Health and Development Studies, a multigenerational cohort that enrolled pregnant women in the East Bay, CA, between 1959 and 1966 (n=14,507 mothers and 18,751 liveborn offspring). We reviewed mothers' medical records to identify those prescribed antihistamines during pregnancy, and diagnoses of HCC in adult (age ≥18 y) offspring were identified by linkage with a population-based cancer registry. Cox proportional hazard models were used to estimate adjusted hazard ratios, with follow-up accrued from birth through cancer diagnosis, death, or last contact. About 15% of offspring (n=2759 of 18,751) were exposed in utero to antihistamines. Chlorpheniramine (51.8%) and diphenhydramine (15.4%) were the 2 most commonly prescribed antihistamines. Any in utero exposure was not associated with HCC (adjusted hazard ratio: 2.76, 95% CI: 0.70, 10.89), but the association differed by timing of exposure. Offspring exposed to antihistamines in the first or second trimester had a higher risk of HCC compared to offspring not exposed (adjusted hazard ratio: 4.64, 95% CI: 1.21, 17.78). Similarly, incidence rates were 4.3 per 100,000 (95% CI: 0.9, 12.6) for offspring exposed in the first or second trimester compared to 1.0 per 100,000 (95% CI: 0.3, 2.1) for offspring not exposed. In utero exposure to antihistamines in early pregnancy may increase the risk of HCC in adulthood.