We have recently noticed an outbreak of chilblain-like lesions in Italy contemporarily to COVID-19 epidemic. Due to the wellknown lockdown-related difficulties to visit the patients, 1 we created a Google form aimed to collect information about patients presenting with these singular clinical findings. An easy to access and quick tool was chosen by the investigators in order to permit the other colleagues to spend the least amount of time, given the severe health emergency. The form was submitted through social media and email to hundreds of Italian dermatologists and paediatricians. In 5 days, we collected 63 patients through the form, but data are still going to be collected. Here the first preliminary results. No significant difference in gender was noticed (57.4% females vs 47.6% males). The median age was 14 years (IQR: 12-16). Feet alone were mostly affected (85.7%) followed by feet/hands together (7%) and hands alone (6%). Pictures of patients were uploaded in 54 patients, with 31/ 54 presenting with erythematous-oedematous lesions (Fig. 1) and 23/54 with blistering lesions (Fig. 2). Pain and itch were equally observed (27% vs. 27%), followed by pain/itch together shown in 20.6% of patients. Asymptomatic lesions were present in 25.4%. Median time from the onset to clinical diagnosis was 10 days (IQR: 6-15). At time of diagnosis, most patients pre-

Significance:The skin is a complex and dynamic organ that performs several vital functions. The maturation process of the skin starts at birth with the adaption of the skin to the comparatively dry environment compared to the in utero milieu. This adaptive flexibility results in the unique properties of infant skin. To deliver appropriate care to infant skin, it is necessary to understand that it is evolving with unique characteristics. Recent Advances: The role of biophysical noninvasive techniques in the assessment of skin development underlines the importance of an objective evaluation of skin physiology parameters. Skin hydration, transepidermal water loss, and pH values are measurable with specific instruments that give us an accurate and reproducible assessment during infant skin maturation. The recording of these values, following standard measurement procedures, allows us to evaluate the integrity of the skin barrier and to monitor the functionality of the maturing skin over time. Critical Issues: During the barrier development, impaired skin function makes the skin vulnerable to chemical damage, microbial infections, and skin diseases, possibly compromising the general health of the infant. Preterm newborns, during the first weeks of life, have an even less developed skin barrier and, therefore, are even more at risk. Thus, it is extremely important to evaluate the risk of infection, skin breakdown, topical agent absorption, and the risk of thermoregulation failure. Future Directions: Detailed and objective evaluations of infant skin maturation are necessary to improve infant skin care. The results of these evaluations should be formed into general protocols that will allow doctors and caregivers to give more personalized care to full-term newborns, preterm newborns, and infants. SCOPE AND SIGNIFICANCEThe skin of preterm newborns, full-term newborns, and infants undergoes a characteristic process of maturation, and therefore, skin care delivered to this spectrum of patients needs to be tailored to the individual patient. The principal aims of safe and effective skin care are to identify the agents that can influence the skin barrier or those that can induce systemic toxicity and avoid their utilization, thereby minimizing the risk of thermoregulation failure, which will protect newborns against potential skin breakdown and loss of its barrier function. TRANSLATIONAL RELEVANCEMany studies have correlated functional infant skin parameters according to age, anatomical site, and the presence of skin or systemic disease. It would be useful to study how these functional parameters change in newborns after the onset of skin infection, skin breakdown, or the application of topical agents. The results of these evaluations could be formed into general protocols, which will allow doctors and wound care providers the ability to give more personalized care to full-term newborns, preterm newborns, and infants. CLINICAL RELEVANCEUnderstanding the characteristics of newborn and infant skin will permit the delivery of a...

Objectives: Ultra-high frequency ultrasonography (UHFUS) is a recently introduced diagnostic technique which finds several applications in diverse clinical fields. The range of frequencies between 30 and 100 MHz allows for high spatial resolution imaging of superficial structures, making this technique suitable for the imaging of skin, blood vessels, musculoskeletal anatomy, oral mucosa, and small parts. However, the current clinical applications of UHFUS have never been analyzed in a consistent multidisciplinary manner. The aim of this study is to revise and discuss the current applications of UHFUS in different aspects of research and clinical practice, as well as to provide some examples of the current work-in-progress carried out in our center. Materials and Methods: A literature search was performed in order to retrieve articles reporting the applications of UHFUS both in research and in clinical settings. Inclusion criteria were the use of frequencies above 30 MHz and study design conducted in vivo on human subjects. Results: In total 66 articles were retrieved. The majority of the articles focused on dermatological and vascular applications, although musculoskeletal and intraoral applications are emerging fields of use. We also describe our experience in the use of UHFUS as a valuable diagnostic support in the fields of dermatology, rheumatology, oral medicine, and musculoskeletal anatomy. Conclusion: Ultra-high frequency ultrasonography application involves an increasing number of medical fields. The high spatial resolution and the superb image quality achievable allow to foresee a wider use of this novel technique, which has the potential to bring innovation in diagnostic imaging.

A subgroup of the transient receptor potential (TRP) channels, including vanilloid 1 (TRPV1), TRPV2, TRPV3, TRPV4, and TRP ankyrin 1 (TRPA1), is expressed in cutaneous peptidergic somatosensory neurons, and has been found in skin non-neuronal cells, such as keratinocytes. Different cancer cells express TRPs, where they may exert either pro- or antitumorigenic roles. Expression and function of TRPs in skin cancers have been, however, poorly investigated. Here, we have studied the distribution and expression of TRPs by immunohistochemistry and messenger RNA (mRNA) in human healthy skin and human keratinocytic tumors, including intraepidermal proliferative disorders (solar keratosis (SK) and Bowen's disease), and non-melanoma skin cancer (NMSC; basal cell and squamous cell carcinomas). Similar TRPV1, TRPV2, and TRPV3 staining was found in keratinocytes from healthy and tumor tissues. TRPA1 staining was increased solely in SK samples. However, the marked TRPV4 staining and TRPV4 mRNA expression, observed in healthy or inflamed skin, was abrogated both in premalignant lesions and NMSC. In a human keratinocyte cell line (HaCaT), TRPV4 stimulation released IL-8, which in turn downregulated TRPV4 expression. Selective reduction in TRPV4 expression could represent an early biomarker of skin carcinogenesis. Whether the cytokine-dependent, autocrine pathway that results in TRPV4 downregulation contributes to NMSC mechanism remains to be determined.