Background and Objectives: Psoriasis is a chronic, immune-mediated inflammatory dermatosis affecting approximately 125 million people worldwide. Biologic therapy (BT) has significantly improved treatment outcomes for moderate-to-severe psoriasis, but real-world adherence to these therapies is not fully understood. This study aimed to evaluate adherence to BT among patients with moderate-to-severe psoriasis and examine how general and treatment-specific beliefs about BT are associated with adherence. Materials and Methods: This cross-sectional study was conducted from March to August 2025 at the University Hospital of Split, Croatia. A total of 122 adults with moderate-to-severe psoriasis receiving interleukin-17 or interleukin-23 inhibitors completed validated Croatian versions of the Beliefs about Medicines Questionnaire–General (BMQ-G), Beliefs about Medicines Questionnaire–Specific (BMQ-S), and the Medication Adherence Report Scale (MARS-5). Adherence was assessed using MARS-5, and beliefs were analyzed using BMQ-G, BMQ-S, and the Necessity–Concerns Framework. Correlation and group-based analyses were used to explore associations between beliefs, adherence, and sociodemographic factors. Results: Adherence to BT was high, with 96.7% of participants reporting that they use their medication as prescribed and 84.4% stating they always followed dosing instructions. Most participants endorsed strong necessity beliefs regarding BT; however, concerns remained common—40.2% reported worry about long-term effects and 15.6% about dependence. General beliefs about medicines influenced treatment-specific perceptions: BMQ-G Overuse scores were negatively correlated with adherence (r = −0.27; p = 0.003) and positively correlated with BMQ-Specific concerns. Participants classified as Distrustful (low necessity, high concerns) made up 31.1% of the cohort and had the highest Harm and Overuse scores. Lower educational attainment was associated with stronger negative beliefs about medicines. Conclusions: Although adherence to BT was high, a considerable proportion of patients expressed residual concerns, especially those with more negative general beliefs about medicines. These findings underscore the importance of assessing medication beliefs in routine care. Tailored education and communication strategies may help address concerns and support long-term adherence to BT in psoriasis.

Background/Objectives: Hidradenitis suppurativa (HS) is a chronic, immune-mediated inflammatory skin disease characterized by painful nodules, abscesses, sinus tracts, and progressive fibrosis. Vascular activation is becoming increasingly acknowledged as an important factor in HS pathogenesis; however, the effects of tumor necrosis factor alpha (TNF-α) blockade on vascular remodeling in HS remain poorly characterized. This study investigated the impact of TNF-α inhibition by adalimumab (ADA) on endothelial and fibroblast-associated markers in HS lesions. Methods: Formalin-fixed paraffin-embedded skin samples from 71 HS patients were analyzed, including treatment-naive (n = 38) and adalimumab-treated (n = 33) cases. Histopathology and immunofluorescence were performed using antibodies against CD31, von Willebrand factor (vWF), α-smooth muscle actin (αSMA), vimentin, Ki-67 (proliferation), and cleaved Caspase-3 (apoptosis). ImageJ software was used to determine the immunoexpression of selected markers and vascular density. Vascular density, assessed as vessel count per mm², was designated as the primary endpoint. Sex-related differences were analyzed as exploratory endpoints. Results: Adalimumab-treated tissue exhibited significantly reduced vascular density (p < 0.01) compared to the treatment-naive group. Conversely, vimentin immunoexpression was significantly higher (p < 0.01) in the adalimumab-treated group. No significant differences were found in endothelial Ki-67 or cleaved Caspase-3 expression between treatment groups, indicating that the observed reduction in vascular density is not associated with direct effects on endothelial cell proliferation or apoptosis, but rather may occur indirectly through attenuation of the pro-angiogenic inflammatory milieu. Exploratory sex-stratified analysis revealed that treatment-naive males had significantly higher endothelial proliferation (Ki-67; p = 0.031) and vimentin expression (p = 0.017) compared to treatment-naive females. In the ADA-treated group, males exhibited significantly lower vascular density (p = 0.036) and higher endothelial apoptosis (p = 0.039) compared to females, whereas females showed a significant increase in vimentin expression following treatment (p = 0.008), suggesting possible sex-dependent differences in vascular remodeling. Conclusions: TNF-α blockade is associated with reduced vascular density, consistent with indirect anti-angiogenic effects, suggesting that adalimumab exerts disease-modifying effects on the microenvironment beyond inflammatory cytokine suppression. Sex-dependent differences in vascular regression underscore the importance of considering sex as a biological variable in HS pathogenesis and treatment response. These results highlight the significance of vascular interactions in HS and support adalimumab as a disease-modifying treatment. These exploratory findings require confirmation in longitudinal studies with paired biopsies.