Cat allergy in children and the effect of the COVID-19 pandemic

Genetic predisposition and increased environmental allergen exposure in cat allergy: The pandemic is a very good example

OBJECTIVE

Domestic cats are among the most common sources of indoor allergens. There was an increase in indoor allergen exposure, especially cats and house dust mites, as people spent more time at home during the COVID-19 pandemic lockdowns. In this study, our aim was to examine the frequency of cat sensitization and ownership after the COVID-19 pandemic and its relationship with other indoor and pollen allergen sensitizations.

METHODS

The data of patients who applied to our clinic between 2018 and 2022, with a history of hypersensitivity reaction after contact with cats and diagnosed with cat allergy by positive skin test or specific immunoglobulin E (sIgE) level, were examined retrospectively. Skin test was performed in accordance with the manufacturer's instructions. sIgE levels against cat allergens were measured using The Phadia CAP System FEIA method.

RESULTS

There has been an increase in the rate of cat ownership (P < 0.001) during the COVID-19 pandemic. The prevalence of cat allergy in 2020 and beyond (5.89%) was significantly higher than the pre-COVID period (4.53%; P < 0.001). The prevalence of concomitant df (dermatophagoides farinae) (1.53-1.58%), dp (dermatophagoides pterynossinus) (1.53-1.48%), and pollen (3.47-3.62%) hypersensitivity before COVID-19 did not differ significantly after COVID, but the prevalence of "penicillium" hypersensitivity before COVID (= 8/5825) was found to be significantly lower (0.14-1.28%).

CONCLUSION

During the pandemic period, both the increase in cat ownership and spending more time indoors seem to have led to an increase in cat allergy. No increase in indoor allergen sensitization other than penicillium accompanying cat allergy was detected.

Aeroallergen Sensitization Patterns and Related Factors in Children With Allergic Rhinitis in Guangzhou

Background: Certain patterns of children's serum immunoglobulin E (IgE) sensitivity to aeroallergens may offer useful clinical insight into forecasting the course and prognosis of allergic rhinitis (AR). The study aimed to investigate the changes in aeroallergen sensitization patterns in children with AR during the last decade and compare the sensitization pre- and post-coronavirus disease 2019 (COVID-19) pandemic in Children who visited our center. Methods: This is a retrospective study, examining the serum IgE of nine aeroallergens from 21,362 children (1-12 years old) from AR who visited Guangzhou Women and Children's Medical Center from June 2013 to June 2023. Result: The dust mites were the most prevalent aeroallergen in Guangzhou, with positive sensitization rates of 74.30% for Dermatophagoides farinae (D. farinae), 73.30% for Dermatophagoides pteronyssinus (D. pteronyssinus), and common ragweed (1.6%) was the lowest. After the COVID-19 pandemic, the sensitization rates to D. farinae were consistent and D. pteronyssinus was slightly decreased while German cockroach, cat, and dog dander were increased. Most of the aeroallergens other than common ragweed were increased in school-age children than preschool stage. Boys have a higher positive rate than girls for D. farinae and D. pteronyssinus. Conclusions: With the unraveling of allergens' sensitization rates in various conditions, avoidance from D. farinae and D. pteronyssinus should still be the most important objectives to maintain in reducing AR episodes.

Different Aspects of COVID-19: "Stay at Home" Increased Cat and Mite Sensitivity in Preschool Children

BACKGROUND

Indoor allergen exposure and senitization is expected to increase significantly during the COVID-19 pandemic. The aim of this study was to assess the impact of this altered allergen exposure on allergen sensitivity patterns in children with asthma.

METHODS

Demographic data, clinical characteristics, and laboratory findings of asthmatic children aged 5 years and younger were assessed May 2019 to May 2020, 1 year after the start of lockdown measures. Those asthmatic children were compared with age- and sex-matched asthmatic peers assessed before the pandemic. Group I included asthmatic children who underwent skin testing within 12 months of the start of the lockdown (n = 112), while Group II included asthmatic children whose skin testing was done before the lockdown (n = 224).

RESULTS

A total of 336 preschool children diagnosed with asthma were evaluated. House dust mite (HDM) and animal dander (cat, dog) senitization rates were significantly higher in Group I than in Group II (66.1% vs. 42.9%; OR: 2.5, 95% CI: 1.6-4.1, p < 0.001 and 8.0% vs. 1.3%; OR: 6.4, CI: 1.7-24.2, p = 0.006, respectively). However, the number of asthma attacks requiring systemic corticosteroid treatment was higher in Group I than in Group II (p = 0.001). The duration of lockdown emerged as a significant risk factor for HDM senitization (p < 0.001, OR: 2.6, 95% CI: 1.6-4.1) and animal allergen senitization (p = 0.006, OR: 6.4, 95% CI: 1.7-27.3).

CONCLUSION

During the pandemic, senitization to indoor allergens, including HDM and animal dander, increased significantly in asthmatic children. This may be attributed to changes in lifestyle, increased time spent indoors and increased pet ownership.

Dog Allergy in Children: A Single-Centered Study

INTRODUCTION

Dogs are among the most commonly allergenic pets for children. Data on risk factors for the development of dog allergy are scarce. This study aimed to evaluate the characteristics of children with dog allergy and identify predictors of symptom development with dog exposure.

METHODS

The study included children with dog allergen sensitization demonstrated by skin prick test (SPT) between September 1, 2019, and December 1, 2022. Demographic, clinical, and laboratory data were collected from the patients' records and interviews with parents.

RESULTS

Dog allergen sensitization was detected by SPT in 548 (5.5%) of 9,907 patients. Of these, 507 patients had complete data and were included in the analysis. The patients' median age was 11 (IQR: 8-15) years, 55.8% were male, 97.6% exhibited polysensitization (pollen 75.1%, cat 69.6%), 83.6% had allergic rhinitis, and 46.2% had asthma. Acute dog exposure caused symptoms in 164 patients (32.3%), most commonly sneezing (n = 97) and nasal symptoms (n = 80). Predictors of acute symptoms in dog-sensitized children were male sex (OR: 0.584 [CI: 0.38-0.87]), dog exposure before 1 year of age (OR: 2.35 [CI: 1.18-4.66]), close contact with a dog owner (OR: 2.93 [CI: 1.78-4.8]), and cat allergy (OR: 2.75 [CI: 1.82-4.1]).

CONCLUSION

Approximately one-third of children with dog sensitization developed symptoms after exposure to the dog. Male sex, direct dog exposure before the age of one, close contact with a dog owner, and cat allergy were identified as predictors of dog allergy.

The Impact of the Pandemic on Cat and Dog Allergies

Objectives

The impact of the COVID-19 pandemic on allergic patients is not clearly understood. The aim of this study is to investigate the changes in sensitivity to cat and dog allergens in patients with respiratory allergies in Istanbul during the COVID-19 pandemic.

Methods

Before the pandemic (March 2018 - March 2020) and during and after the pandemic (March 2020 - March 2022), a total of 5499 patients who underwent skin testing were retrospectively evaluated. The patients' age, gender, diagnosis, total IgE, and eosinophil values were recorded. Patients were divided into two groups: 2-6 years old and 7 years and older. The frequency of sensitization to cats and dogs was investigated in both groups before and after the pandemic.

Results

The median age of the 5499 children included in the study was 77 months, with a range of 2 to 221 months. Furthermore, 55.7% of the children were male. Of the children, 59.1% were examined before the pandemic, and 40.9% during and after the pandemic. During the examinations, allergic rhinitis was identified in 1628 children (29.6%), asthma in 1829 children (33.3%), and both asthma and allergic rhinitis in 2042 children (37.1%). Allergies to cats were found in 247 children (4.5%), and to dogs in 166 children (3.0%). When comparing the age groups, the frequency of cat allergy in the 7-years and older group was found to have decreased compared to the pre-pandemic period, and the statistical difference was close to significance (p=0.08). However, regarding dog allergy, in the 7 years and older group, the sensitivity to dogs, which was 5.6% before the pandemic, had decreased to 2.6% during the pandemic, and this decrease was found to be statistically highly significant (p<0.001).

Conclusion

Environmental allergen exposure has a significant impact on the phenotype of allergic diseases. Changes in patients' lifestyles and increased time spent at home during the pandemic may have led to a decrease in contact with outdoor cat and dog allergens, resulting in a reduced frequency of cat and dog sensitivity. Additionally, the introduction of mask-distance-handwashing/disinfection rules during the pandemic is believed to have reduced contact with cat and dog allergens, potentially contributing to a decrease in allergy frequency.

Increasing Prevalence of Sensitization to Cat/Dog Allergens in the COVID-19 Pandemic

INTRODUCTION

Cat and dog allergens are common indoor triggers for respiratory allergies such as allergic rhinitis and asthma. This study aims to evaluate the prevalence of cat and dog allergies in adults and analyze changes during the COVID-19 pandemic.

METHODS

We retrospectively analyzed the medical records of 8,102 patients who visited an allergy clinic and underwent skin prick testing (SPT) from March 2018 to March 2022: 2 years before and 2 years during the pandemic. Demographic information, clinical attributes, and laboratory results were examined based on patient records.

RESULTS

Of 8,102 SPTs performed, 400 (4.9%) were sensitized to cat allergen and 289 (3.6%) to dog allergen. Allergic rhinitis was the predominant clinical diagnosis in both groups. Of the 400 subjects exposed to cats, 240 (60%) experienced allergic symptoms, while of the 289 subjects exposed to dogs, 65 (22.5%) experienced allergic symptoms during exposure. Within the cat-sensitized group, anaphylaxis was observed in 5 patients (1.3%), while no cases of anaphylaxis were reported in the dog-sensitized group. Compared to the pre-pandemic period, patients presenting during the pandemic had higher rates of cat and dog sensitization (5.7% vs. 4.1%; p < 0.05, 5.2% vs. 1.7%; p < 0.05).

CONCLUSION

During the COVID-19 pandemic, there was an increase in cat and dog allergies among adults. Increased exposure to pet antigens, both directly and indirectly, has resulted in more people becoming sensitized to cats or dogs.

Characteristics of children with cat sensitivity: a prospective cross-sectional study

BACKGROUND

Animal dander is one of the most common respiratory allergens in children, and there is evidence that cat sensitivity is a risk factor for asthma and allergic rhinitis. In this study, it was aimed to evaluate children with cat sensitivity and to identify their demographic and clinical characteristics.

METHODS

Patients who were found to be sensitive to cats following skin prick tests performed in our allergy clinic over a period of one year (and two control groups), were included in the study. Patients in the study and control groups filled in a questionnaire including demographic and clinical characteristics.

RESULTS

The prevalence of cat sensitivity in our allergy clinic was 6% (182/3033). The most common diagnoses in patients were 41.8% allergic rhinitis, 25.8% asthma, and 13.2% allergic rhinitis + asthma. Allergic rhinitis symptoms were the most prevalent symptom associated with cat contact (29.4%), whereas 28% of the patients were asymptomatic. Only 17.3% had a cat at home and 13.4% had cat exposure apart from home but having a cat at home was significantly higher than the control groups (p < 0.05). Eosinophilia was present in 54.6% of the patients, and 17.3% had blood tIgE levels of >1000 IU/mL. Eosinophilia and tIgE levels were significantly higher than both control groups (p < 0.05).

DISCUSSION

Cat ownership can affect the development of cat sensitivity but the majority of patients with cat sensitivity are not cat owners. Elevated tIgE levels (> 1000 IU/mL) may be associated with cat sensitivity, these patients should be evaluated for cat sensitivity, even if they do not report symptoms with cat contact.