Ekaterina Emelyanova

Objective: The aim of the study was to evaluate the dynamics of skin temperature at the injection points of botulinum toxin type A in the forehead area at different time stages as a marker of the vasomotor response and restoration of microcirculation after aesthetic botulinum therapy. Methods: The prospective study included 126 patients (19–59 years old, mean age 34.4 ± 1.2 years) who underwent injections of botulinum toxin type A at standard points of m. frontalis, m. procerus, and m. corrugator supercilii. Skin temperature was recorded with an infrared thermal imager at nine standardized points (P1–P9) at the following stages: before the procedure (T0), immediately after (T1), after 30 min (T2), after 14 (T14) and 30 (T30) days. The analysis was performed using analysis of variance with repeated measures and post hoc tests (p < 0.05). Results: A typical three-phase pattern of temperature response was revealed: an immediate decrease in temperature at all points immediately after injections (T1, −1.7–4.8% relative to the baseline, p < 0.001), subsequent reactive hyperemia after 30 min (T2, an increase of 2.35–5.8% at points P1, P2, P4–P7) and normalization of indicators by T14–T30. The most pronounced and stable changes were recorded at the interbrow points P7–P9, projecting to m. corrugator supercilii and m. procerus, which reflects their higher functional and vascular activity. Conclusions: Infrared thermography allows for objective recording of the phasic vasomotor response of the skin to injections of botulinum toxin type A, can be used to assess individual vascular response, and may aid in individualized treatment planning for aesthetic botulinum therapy.

Objective: The objective of this study was to clarify the connection between BTX-A injections and local changes in skin temperature and to assess the correlation between post-BTX-A injection facial vascular hyperthermia and subcutaneous adipose tissue thickness (SAT) in the frontal area using thermography. Methods: The study involved 30 patients (mean age 42 ± 0.5 years; 18 women, 12 men). Facial skin temperature was measured via thermography (Thermo GEAR G30) before, immediately after, and 20 min after subcutaneous injection of BTX-A with hemagglutinin complex, gelatin (6 mg), and maltose monohydrate (12 mg). SAT development was graded by combined visual-palpation assessment. Statistical analysis included Student’s t-test and the Mann–Whitney U-test. Results: Biphasic thermal response: immediately post-injection: Significant decrease in min (−1.1 °C) and mean (−0.3 °C) facial temperatures (p < 0.05); 20 min post-injection: pronounced increase in mean (+1.5 °C), max (+1.3 °C), and min (+1.6 °C) temperatures (p < 0.001), attributed to BTX-A-induced vasodilation and local inflammation. Subjects with pronounced SAT exhibited significantly higher baseline temperatures (Me = 33.1 °C vs. 29.8 °C; p < 0.001) and more intense hyperthermic responses (+1.6 °C mean increase vs. +1.1 °C in low-SAT group; p < 0.001). Pronounced SAT was predominantly female (10/15; p < 0.05) and linked to higher BMI (33.3% overweight vs. 0% in low-SAT; *p = 0.036*). Conclusions: SAT thickness is a key determinant of post-BTX-A vascular hyperthermia, with pronounced SAT predicting stronger reactions. Practical Recommendation: Targeted local hypothermia (+4 °C to +8 °C for 5–7 min post-injection, adjustable by SAT thickness) mitigates hyperemia, edema, hematoma risk, and potential toxin diffusion, especially in high-SAT individuals.