<b>Association Between Household PET Ownership And The Risk Of Skin Allergies And Pulmonary Disorders: </b><b>A</b><b> Retrospective Case-Control Study In Karachi</b>

Background: Asthma is a prevalent chronic lung disease in children, predisposed by environmental factors such as household pet ownership. Allergic predisposition may adapt the relationship between pet exposure and asthma possibility. Objective: To evaluate the association between household pet ownership and asthma risk in children aged 2 to 18 years and to assess how allergic predisposition affects this relationship. Methodology: A retrospective case-control study was conducted involving 2500 children (1250 asthma cases and 1250 matched controls) aged 2 to 18 years. Cases were physician-diagnosed asthmatic children confirmed by spirometry and skin prick testing. Controls were matched by age, sex, and residence, and had no history of asthma or chronic respiratory diseases. Data on pet ownership, allergic illnesses, and environmental exposures were collected via structured questionnaires. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for potential confounders. Results: The mean age of participants was 9.0 ± 2.6 years; 66.0% were male. Allergic rhinitis was present in 79.2% of participants, and 21.8% had atopic dermatitis. Household pet ownership was reported by 40.2% of participants, with cats being the most common pet (17.0%), followed by dogs (14.7%) and birds (8.5%). Among children with allergic predisposition, cat ownership was significantly associated with increased odds of asthma (OR = 1.6; 95% CI: 1.2–2.1). Dog and bird ownership also showed moderate associations (OR = 1.3; 95% CI: 1.0–1.7 and OR = 1.4; 95% CI: 1.1–1.8, respectively). No significant associations were observed in non-allergic children. Conclusions: Household pet ownership, particularly cats and birds, is associated with increased asthma risk in children with allergic predisposition. These findings highlight the importance of considering allergic status when assessing environmental risk factors for pediatric asthma.