Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(3):5450 1 Line-Field Confocal OCT and Clinical Correlation in Plaque Psoriasis Treated with Calcipotriol/ Betamethasone Dipropionate and Polyaphron Dispersion Technology Martina Dragotto1, Eugenio Capalbo1, Pietro Rubegni1, Emanuele Trovato1 1 Dermatology Section, Department of Medical, Surgical and Neurological Science, University of Siena, Siena, Italy Key words: Psoriasis, Small-molecule, Obesity, Weight, BMI Citation: Dragotto M, Capalbo E, Rubegni P, Trovato E. Line-field confocal OCT and clinical correlation in plaque psoriasis treated with calcipotriol/betamethasone dipropionate and polyaphron dispersion technology. Dermatol Pract Concept. 2025;15(3):5450. DOI: https:// doi.org/10.5826/dpc.1503a5450 Accepted: February 20, 2025; Published: July 2025 Copyright: ©2025 Dragotto et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Emanuele Trovato, Unit of Dermatology, Department of Medical, Surgical and Neurosciences, University of Siena, Siena, Italy. Orcid ID: 0000-0001-8301-9206. E-mail: emanuele.trovato@unisi.it Introduction Psoriasis (PsO) is a chronic inflammatory skin condition driven by inflammation, leading to keratinocyte hyperproliferation and abnormal differentiation, with both innate and adaptive immune responses playing key roles. PsO presents as well- demarcated erythematous plaques covered with white or sil- very scales, varying in size and thickness [1]. Histologically, PsO is characterized by acanthosis, inflammatory infiltration, and neovascularization. Mild psoriasis is defined as body sur- face area (BSA) ≤10% or a psoriasis area and severity index (PASI) ≤10. Topical treatments, used alone or in combination with systemic therapies, must overcome challenges such as plaque thickness and drug pharmacokinetics. Effective topical treatments require an optimal combination of formulation and active ingredients. Line-field optical coherence tomography (LC-OCT) is a non-invasive imaging technique providing de- tailed in vivo visualization of skin architecture, facilitating the diagnosis and monitoring of inflammatory skin diseases [2,3]. Polyaphron dispersion (PAD) technology is a novel drug delivery system that enhances drug penetration through a nonpolar solvent core encapsulated in a multilayered struc- ture of surfactants, oil, and water, forming a three-dimen- sional architecture around the oil droplet. In vitro studies have demonstrated significantly higher drug flux through human epidermis with a calcipotriene/betamethasone dipro- pionate (CAL/BDP) PAD-cream compared to an oil-based CAL/BDP gel [4]. This study evaluated LC-OCT for moni- toring therapeutic responses in PsO following treatment with CAL/BDP PAD-cream (50 mcg/g + 0.5 mg/g). Case Presentation The study was conducted at the Dermatology Unit, Univer- sity Hospital of Siena, Italy, in compliance with the Declara- tion of Helsinki. Ten patients (5 males, 5 females) with mild 2 Research Letter | Dermatol Pract Concept. 2025;15(3):5450 psoriasis on the elbows participated, providing informed consent. None had received systemic therapy during the study. The clinical severity was evaluated using a lesion score (LS), designed considering erythema, desquamation, and in- filtration. LC-OCT was performed at baseline after four and eight weeks. Paraffin oil was applied to the skin surface prior to imaging to minimize refraction. Patients applied CAL/ BDP PAD-cream, two fingertip units, once daily for four weeks, then twice weekly for the subsequent four weeks. Patients were instructed to avoid emollients or oil-based baths throughout the observation period. At baseline, le- sions appeared as moderately infiltrated erythematous- desquamative plaques (mean LS 6.8±1.3) (Figure 1A). LC-OCT revealed increased corneal and epidermal thick- ness with hypergranulosis. The dermo-epidermal junction (DEJ) appeared as a hypo-reflective wavy line, with hypo- reflective canalicular vessels visible within dermal papillae (Figure 1B). By week 4, patients reported clinical improve- ment, with reduced hyperkeratosis and infiltrate (mean LS 3.2±0.8) (Figure 1C). LC-OCT demonstrated normalization of corneal layer thickness and reduced DEJ undulation, though complete flattening was not achieved. Hypergran- ulosis remained unchanged (Figure 1D). At week 8, seven patients achieved complete remission (mean LS 1.1±0.9) (Figure 1E). LC-OCT findings showed DEJ flattening and resolution of hypergranulosis (Figure 1F). All patients com- pleted the study without side effects. Conclusion PAD technology enhances drug penetration and supports pa- tient adherence to topical treatments. LC-OCT is a valuable tool for accurate, non-invasive monitoring of treatment response, offering deeper insights than do traditional clinical evaluations. Standardized digital parameters are needed to objectively quan- tify lesion characteristics and their changes during therapy. References 1. Trovato E, Rubegni P, Prignano F. Place in therapy of anti-IL-17 and 23 in psoriasis according to the severity of comorbid- ities: a focus on cardiovascular disease and metabolic syn- drome. Expert Opin Biol Ther. 2022;22(12):1443–8. DOI: 10.1080/14712598.2022.2093106. 2. Orsini C, Trovato E, Cortonesi G, et al. Line-field confocal opti- cal coherence tomography: New insights for psoriasis treatment monitoring. J Eur Acad Dermatol Venereol. 2024;38(2):325–31. DOI: 10.1111/jdv.19568. 3. Verzì AE, Broggi G, Micali G, Sorci F, Caltabiano R, Lacarrubba F. Line-field confocal optical coherence tomography of psoriasis, eczema and lichen planus: a case series with histopathological correlation. J Eur Acad Dermatol Venereol. 2022;36(10):1884–9. DOI: 10.1111/jdv.18293. PMID: 35666617 4. Praestegaard M, Steele F, Crutchley N. Polyaphron Dispersion Technology, A Novel Topical Formulation and Delivery System Combining Drug Penetration, Local Tolerability and Convenience of Application. Dermatol Ther (Heidelb). 2022;12(10):2217–31. DOI: 10.1007/s13555-022-00794-y. PMID: 36050567. Figure 1. (A) Clinical presentation of plaque psoriasis at baseline. (B) Line-field confocal optical coher- ence tomography (LC-OCT) examination at baseline. Vertical section showing an increase in corneal layer and in epidermal thickness with hypergranulosis, and a well-defined DEJ was evident as a hy- po-reflecting line with a wavy appearance; hypo-reflective canalicular vessels were visible within dermal papillae. (C) Clinical presentation at 4-week follow-up. (D) LC-OCT examination at 4-week follow-up. Vertical section showing a normalization of the thickness of the corneal layer, a reduced undulation of the dermo-epidermal junction, and hypergranulosis of the epidermidis. (E) Clinical presentation at 8-week follow-up. (f) LC-OCT examination at 8-week follow-up. Vertical section showing a flattening of the dermo-epidermal junction and resolution of hypergranulosis.