also been used to evaluate the efcacy of an oral micronutrient supplement on preservation of skin quality through the measurement of skin thickness and density [99, 100]. Conclusion While ultrasound has been used in dermatology for more than 40 years, its uses have continued to evolve with improvements in technology. Today, there are a few dermatologic lesions with pathognomonic sonographic features. One example is the “jellyfsh” sign described in some cases of dermatofbrosarcoma protuberans [101]. Other examples include the “saw-tooth” pattern of cellulite [102–104]. Pathognomonic ultrasonographic features are likely to increase with integration of higher frequency ultrasound devices in clinical practice; for future work with HFUS, a core international task force group formed by 15 physicians from 11 countries called the DERMUS (dermatologic ultrasound) group recommends dermatologists use Doppler-capable ultrasound devices with a frequency of at least 15- to 22-MHz in all ultrasound examinations of the skin [18]. Levy et al. Ultrasound J (2021) 13:24 Page 9 of 12 While there is support for use of ultrasound in future dermatological practice, there are a number of limitations associated with the use of this tool. One major limitation is the skill of the operator. Consequently, the DERMUS group suggests utilizing ultrasound at least 300 times per year to achieve minimum competency. Similarly, it is strongly advised that the dermatologist functions as the sonographer because of the years of training in dermatologic pathologies and ability to correlate histology with clinical presentation of cutaneous lesions [18]. As frequency advancements in ultrasonography continue, the broad applications of this imaging modality will continue to grow. Ultrasound is a fast, safe and readily available tool that can aid in diagnosing, monitoring and treating dermatologic conditions by providing more objective assessment measures. Abbreviations HFUS: High-frequency ultrasound; MHz: Megahertz; TBDP: Total body digital photography; RCM: Refectance confocal microscopy; OCT: Optical coherence tomography; μm: Micrometers; BCC: Basal cell carcinoma; SCC: Squamous cell carcinoma; SLEB: Subepidermal low-echogenic band; MF: Mycosis fungoides; CASPAR: Classifcation criteria for psoriatic arthritis; HS: Hidradenitis suppurativa; AD: Atopic dermatitis; CSAMI: Cutaneous Sarcoidosis Activity and Morphology Instrument; IFAG: Idiopathic facial aseptic granuloma; PWS: Port-wine stain; AV: Arteriovenous. Acknowledgements Not applicable. Authors’ contributions JL and SCC had the concept for the review article and performed the majority of the literature search, with assistance from DLB and NH. JJJ and XY contributed to the imaging and planing of the work that led to this manuscript. DLB, NH, JL and SCC drafted the article, with all authors critically revising the work. All authors read and approved the fnal manuscript. Funding Not applicable. Availability of data and materials Not applicable. Declarations Ethics approval and consent to participate: Not applicable. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interest. Author details 1 Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA. 2 Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, USA. 3 Department of Biomedical Informatics, Emory University, Atlanta, GA, USA. 4 Winship Cancer Institute, Emory University, Atlanta, GA, USA. 5 Department of Dermatology, Duke University School of Medicine, Duke Clinic, 40 Duke Medicine Cir, Clinic 3K, Durham, NC 27710-4000, USA. Received: 22 October 2020 Accepted: 27 March 2021 References 1. Bhattacharya A, Young A, Wong A, Stalling S, Wei M, Hadley D (2017) Precision diagnosis of melanoma and other skin lesions from digital images. AMIA Jt Summits Transl Sci Proc 2017:220–226 2. Schneider SL, Kohli I, Overview of Ultrasound Imaging Applications in Dermatology Nouf Almuhanna1,2,3 , Ximena Wortsman4,5,6 , Iris Wohlmuth-Wieser1,2,7, Misaki Kinoshita-Ise8 , and Raed Alhusayen1,2 Abstract