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Actinic keratosis (AK) classification relies on clinical characteristics limited to the skin's surface. Incorporating sub‐surface evaluation may improve the link between clinical classification and the underlying pathology. We aimed to apply dynamic optical coherence tomography (D‐OCT) to characterize microvessels in AK I‐III and photodamaged (PD) skin, thereby exploring its utility in enhancing clinical and dermatoscopic AK evaluation. This explorative study assessed AK I‐III and PD on face or scalp. AK were graded according to the Olsen scheme before assessment with dermatoscopy and D‐OCT. On D‐OCT, vessel shapes, −pattern and ‐direction were qualitatively evaluated at predefined depths, while density and diameter were quantified. D‐OCT's ability to differentiate between AK grades was compared with dermatoscopy. Forty‐seven patients with AK I‐III (n = 207) and PD (n = 87) were included. Qualitative D‐OCT evaluation revealed vascular differences between AK grades and PD, particularly at a depth of 300 μm. The arrangement of vessel shapes around follicles differentiated AK II from PD (OR = 4.75, p < 0.001). Vessel patterns varied among AK grades and PD, showing structured patterns in AK I and PD, non‐specific in AK II (OR = 2.16,p = 0.03) and mottled in AK III (OR = 29.94, p < 0.001). Vessel direction changed in AK II‐III, with central vessel accentuation and radiating vessels appearing most frequently in AK III. Quantified vessel density was higher in AK I‐II than PD (p ≤ 0.025), whereas diameter remained constant. D‐OCT combined with dermatoscopy enabled precise differentiation of AK III versus AK I (AUC = 0.908) and II (AUC = 0.833). The qualitative and quantitative evaluation of vessels on D‐OCT consistently showed increased vascularization and vessel disorganization in AK lesions of higher grades. [ABSTRACT FROM AUTHOR]

There is a lack of efficacious topical treatments for patients suffering from psoriatic nail disease (PND). We investigated the efficacy of Calcipotriol‐Betamethasone Dipropionate (Cal/BD) foam with and without ablative fractional laser (AFL) in patients with PND. A total of 144 nails from 11 patients were treated in a 24‐week long, open‐label, randomized, intra‐patient controlled proof‐of‐concept hybrid trial. In addition to daily Cal/BD foam application, half of each patient's psoriatic nails were randomized to receive optical coherence tomography (OCT)‐guided AFL treatment at baseline, 6‐, and 12‐week follow‐ups. In‐clinic assessment (N‐NAIL), patient‐reported outcomes (PROMs), and drug consumption were supplemented by remote evaluation of 15 subclinical OCT features, smartphone app‐based safety monitoring, and photo‐based assessment (NAPSI). After 24 weeks of Cal/BD foam treatment, patients achieved a significant improvement (p < 0.001) in both clinical (N‐NAIL −76%, NAPSI −68%) and subclinical (OCT −43%) PND severity as well as a 71% reduction in PROMs. AFL‐assisted Cal/BD treatment led to higher clinical (N‐NAIL −85%, NAPSI −78%) and OCT‐assessed (−46%) reduction of PND signs than Cal/BD alone (N‐NAIL −66%, NAPSI −58%, OCT −37%), but did not reach statistical significance. Smartphone app images documented adverse events and mild local skin reactions, particularly erythema (75%), laser‐induced swelling (28%), and crusting (27%). This hybrid trial demonstrated a reduction in clinical NAPSI and N‐NAIL scores, subclinical OCT features, and PROMs, suggesting that Cal/BD foam is a safe and efficacious treatment for PND. Larger trials are warranted to prove the clinical benefit of AFL pretreatment as a Cal/BD delivery enhancer. [ABSTRACT FROM AUTHOR]

The tape stripping technique is increasingly used in research regarding skin barrier function. However, number of tape strips varies between studies, and literature considering advancement into stratum corneum/epidermis in relation to number of tape strips is scarce. The aim of this pilot study was to assess the advancement through epidermis using tape stripping technique in healthy volunteers. A total of ten healthy volunteers were included. From all volunteers 0, 5, 15 and 35 consecutive tape strips (D-squame) were taken from four adjacent skin areas on the middle volar forearm, followed by Reflectance Confocal Microscopy (RCM) of the four areas to assess epidermal thickness. Squame Scan was used to determine amount of protein removed. Stratum corneum was completely removed in all volunteers after 35 tape strips. Advancement into epidermis was predominantly achieved by the first 15 tape strips, removing 25% of the total epidermis, whereas 35 tape strips removed 33% of epidermis. Protein removal per tape decreased with increasing depth. Information on advancement into the epidermis according to number of tape strips taken, is a significant step forward. The possibility to obtain samples from different layers of epidermis may lead to an improved understanding of skin barrier properties. [ABSTRACT FROM AUTHOR]