Abstract: 【Abstract】 Objective To investigate the association between eczema and the use of antihypertensive drugs in middle-aged and elderly patients. Methods This study was a prospective case-control study. Middle-aged and elderly patients with hypertension receiving antihypertensive drugs were collected from the Dermatology Departments of Qidong People′s Hospital and Changshu Traditional Chinese Medicine Hospital between March 1, 2023, and August 31, 2024. The patients were divided into 2 groups: the observation group consisting of outpatients diagnosed with eczema, and the control group consisting of outpatients with non-eczema skin diseases. General information was collected from both groups, including types of antihypertensive drugs, duration of drug use, time from initiation of antihypertensive therapy to rash onset, proportion of patients with rash resolution after switching antihypertensive drugs, and time to marked improvement in rashes. Comparisons between the two groups were performed using the two independent samples t-test; the chi-square test was used to compare categorical data between groups; logistic regression analysis was performed to evaluate associations between antihypertensive drug use and eczema. Results The observation group included 239 patients （115 males and 124 females）, with the age being 67.5 ± 8.6 years and duration of antihypertensive drug use being 9.0 ± 3.3 years. The control group included 326 patients （160 males and 166 females）, with the age being 68.8 ± 9.3 years and duration of antihypertensive drug use being 10.7 ± 4.8 years. There were no significant differences in gender, age, or duration of antihypertensive drug use between the two groups （all P > 0.05）. In the observation group, 35 （14.6%）, 50 （20.9%）, 30 （12.6%）, 101 （42.3%）, and 23 （9.6%） patients used angiotensin-converting enzyme inhibitors, angiotensin Ⅱreceptor blockers, β-blockers, calcium channel blockers （CCBs）, and diuretics, respectively; in the control group, 58 （17.8%）, 92 （28.2%）, 55 （16.9%）, 74 （22.7%）, and 47 （14.4%） patients used the corresponding drugs respectively. Logistic regression analysis for the association between different types of antihypertensive drugs and eczema showed that only the use of CCBs was associated with the occurrence of eczema （P < 0.001）, with an odds ratio （OR） of 2.49 （95% CI: 1.26 - 4.54）. Among patients using the 5 classes of antihypertensive drugs, significant differences were observed in the time from drug initiation to rash onset and the proportion of patients with rash resolution after switching antihypertensive drugs （both P < 0.05）. Patients receiving CCBs showed longer time from drug initiation to rash onset （33 ± 13 months） and a higher proportion of patients with rash resolution after switching drugs （84.2%） than those receiving the other 4 classes of antihypertensive drugs （all P < 0.05）. However, no significant difference was observed in the time from drug switching to rash resolution among the 5 drug classes （P = 0.166）. Conclusions The use of CCBs seemed to be associated with the occurrence of eczema in middle-aged and elderly patients with hypertension, with a relatively long interval between drug initiation and rash onset. The underlying mechanisms require further investigation.

Key words: Eczema, Middle-aged and elderly Patients, Antihypertensive drugs, Prospective case control study