The Role of High-Frequency Ultrasound and Color Doppler in Assessing Acne Treatment Response

A prospective, single-center study evaluated the utility of high-frequency ultrasound (HFUS) and color Doppler flow imaging (CDFI) as non-invasive tools for assessing treatment response in patients with moderate-to-severe acne vulgaris.¹ HFUS provides objective, quantitative insight into deeper pathological changes, including nodulocystic involvement and dermal remodeling, while CDFI adds an additional dimension by visualizing real-time blood flow, serving as a surrogate marker for inflammatory activity.

Background

HFUS is an imaging modality that uses sound waves at frequencies ≥15 MHz to generate detailed, real-time images of the skin and underlying structures. In acne, HFUS can quantify lesion size, depth, and structural changes that are not visible on clinical examination.² CDFI complements HFUS by incorporating Doppler technology to assess blood flow within tissues. It provides real-time visualization of vascularity within acne lesions, allowing clinicians to evaluate inflammatory activity based on the presence and intensity of blood flow signals.³

“Currently, clinical assessment of moderate-to-severe acne vulgaris primarily relies on visual observation and palpation,” the authors wrote. “This subjective approach can result in premature treatment cessation before deep-seated lesions are fully resolved, leading to recurrence and contributing to inter-observer variability, hindering consistent treatment outcomes.”

Trial Design and Results

In this trial, 30 patients (mean age 21.1 years) were followed over 12 weeks while receiving standardized systemic and topical therapies, with optional adjunctive phototherapy. Assessments were conducted at baseline, week 4, and week 12 using clinical grading (Pillsbury) alongside ultrasound-based scoring (SSSA).

HFUS demonstrated significant improvements across multiple structural parameters, including reductions in nodule and cyst size, lesion depth, dermal thickness, and epidermal elevation (p < 0.001). It also identified decreases in lesion fusion, intracystic hyperechogenicity, and subcutaneous fat involvement over time. Notably, HFUS consistently detected a higher number of nodules and cysts compared to manual clinical counting at all time points, highlighting its sensitivity in identifying subclinical and deep lesions.

CDFI findings further supported treatment response, with significant reductions in vascular flow (Adler grading) over time (p < 0.001), reflecting decreased inflammatory activity. While no significant change was observed between baseline and week 4, marked reductions were evident by week 12, suggesting that vascular changes may lag behind early clinical improvement.

At baseline, there was perfect agreement between clinical and ultrasound grading (κ=1.0). However, concordance declined substantially after treatment (κ=0.3), with HFUS indicating greater residual disease severity in 56.7% of patients.

Clinical Implications and Limitations

These findings have important clinical implications, as the authors noted. Persistent deep lesions detected by HFUS, even in patients considered clinically improved, may contribute to relapse and scarring if treatment is prematurely discontinued. Incorporating HFUS/CDFI into routine practice may therefore support more informed decisions regarding treatment duration and intensity, particularly in nodulocystic acne.

The researchers also acknowledged study limitations, including a small sample size and the inherent differences between clinical and ultrasound grading systems. While clinical grading reflects overall facial severity, HFUS focuses on the most severe lesion, which may contribute to discordance post-treatment. Nonetheless, this reinforces the value of a multimodal approach to acne assessment.

Overall, HFUS combined with CDFI offers a sensitive, objective, and reproducible method for evaluating disease severity and therapeutic response in moderate-to-severe acne vulgaris. By enabling visualization of both superficial and deep inflammatory processes, this approach enhances clinical assessment, supports individualized treatment strategies, and may ultimately reduce recurrence and scarring. Larger studies are needed to validate these findings and to develop integrated scoring systems that incorporate both clinical and imaging-based metrics.

References

1. Zheng L, Fu X, Qiu X, et al. The Value of High-Frequency Ultrasound and Color Doppler Flow Imaging in Assessing the Efficacy of Moderate-to-Severe Acne Vulgaris: A Prospective Single-Arm Study. J Cosmet Dermatol. 2026;25(4):e70793. doi:10.1111/jocd.70793

2. Wu X, Jiang T. High-Frequency Ultrasonography Evaluation of Acne by Thickness and Power Doppler Vascular Analysis. J Ultrasound Med. 2022;41(10):2517-2525. doi:10.1002/jum.15941

3. Odak M, De Jesus O. Vascular Technology Color Flow Imaging. In: StatPearls. Treasure Island (FL): StatPearls Publishing; October 31, 2022.