Optical coherence tomography in diagnosis of inflammatory scalp disorders.

BACKGROUND: The common inflammatory scalp disorders share similar clinical manifestations, and patient work up require invasive, undesirable diagnostic procedures like biopsy to ensure correct diagnosis. Optical coherence tomography (OCT) is a non-invasive high-resolution imaging modality that has found a valuable tool to assist in the diagnose and evaluation of different skin diseases. OBJECTIVES: To describe the structural and vascular dynamic OCT (D-OCT) findings of inflammatory scalp disorders including scalp psoriasis, seborrhoeic dermatitis and contact dermatitis and to compare trichoscopy and OCT features. METHODS: Subjects with diagnosis of seborrhoeic dermatitis, psoriasis or contact dermatitis were enrolled in this study. OCT scans were taken on involved scalp, and the same scalp regions were evaluated by trichoscopy and compared with healthy scalp. RESULTS: A total of fourteen subjects (two healthy controls, four seborrhoeic dermatitis, five psoriasis and three contact dermatitis) participated. D-OCT imaging of vascular pattern in healthy scalp and the inflammatory scalp disorders were described. D-OCT images could enhance the clinician's ability to distinguish psoriasis from seborrhoeic dermatitis by objectively detect and assess red loop density. In scalp contact dermatitis, the vessels of the deep plexus were more dilated and fewer in number than those found in seborrhoeic dermatitis. CONCLUSION: Dynamic OCT provides information that more clearly elucidates changes at the level of the superficial and deep plexuses without invasively interfering with superficial structures. In the context of inflammatory scalp disorders, this is useful to discern disorders with overlapping symptoms and minimize the use of invasive biopsies to diagnose.

OCT image atlas of healthy skin on sun-exposed areas.

BACKGROUND: Skin cancer represents the most prevalent type of cancer in the United States. Excision of these lesions can leave significant scarring, and a delay in the diagnosis of malignant melanoma could result in metastasis or death. Therefore, developing technology and criteria to accurately diagnose these cancers is of particular importance to the medical community. While biopsy can lead to scarring and infections, dermoscopy and confocal microscopy offer noninvasive imaging methods but are also limited in their ability to determine tumor depth and margins. Optical coherence tomography (OCT) is a promising imaging method that uses near-infrared light backscattering to image structures underneath the surface of the skin. The purpose of this study is to provide examples of variations across different skin locations and to identify common themes that occur with aging and sun exposure, most notably thinning of the epidermis and loss of a distinct dermal-epidermal junction. METHODS: Optical coherence tomography images were taken using the VivoSight swept-source OCT. Images were taken from a 23-year-old man (Subject 1) and an 89-year-old man (Subject 2), both with Fitzpatrick Skin Type I, who did not have any prior skin conditions. We investigated the regions of the body that represent sun-exposed areas. RESULTS: Results including OCT images taken from 19 predominately sun-exposed areas are shown in Figure 2-Figure 20. CONCLUSION: The 2 sets of images demonstrate the variety that exists within OCT imaging of healthy skin, and thus, a comprehensive understanding of the variation in normal skin imaging using OCT is critical to be able to distinguish and diagnose skin cancers when present.

The influence of gender and age on the thickness and echo-density of skin.

BACKGROUND: The more recent use of ultrasound scanning allows a direct measurement on unmodified skin, and is considered to be a reliable method for in vivo measurement of epidermal and dermal thickness. The objective of this study was to assess the influence of gender and age on the thickness and echo-density of skin measured by high frequency ultrasonography (HFUS). MATERIALS AND METHODS: This study was carried out on 30 healthy volunteers (17 female, 13 male) with age range of 24-61 years old. The thickness and echo-density of dermis as well as epidermal entrance echo thickness in five anatomic sites (cheek, neck, palm, dorsal foot, and sole) were measured using two different types of B mode HFUS, 22 and 50 MHz frequencies. RESULTS: The epidermal entrance echo thickness and thickness of dermis in males were higher than females, which was statistically significant on neck and dorsum of foot. The echo-density of dermis was higher in females on all sites, but was only statistically significant on neck. The epidermal entrance echo thickness and thickness of dermis in young age group was statistically higher than old group on sole and dorsal of the foot respectively. Overall, the skin thickness decreased with age. CONCLUSION: High frequency ultrasonography method provides a simple non-invasive method for evaluating the skin thickness and echo-density. Gender and age have significant effect on these parameters. Differences in study method, population, and body site likely account for different results previously reported.

The effects of water exposure on biophysical properties of normal skin.

BACKGROUND: Water exposure is an influential factor in some common dermatoses. It has also been shown that water has an effect on barrier function and biophysical properties of skin. The aim of this study was to evaluate the effect of water immersion on biophysical properties of normal skin. PARTICIPANTS & METHODS: Twenty healthy volunteers participated in this study. The volar aspect of volunteer's forearm was immersed in tap water for 30 min a day for five consecutive days. Biophysical skin parameters including TEWL, skin pH, capacitance, erythema and sebum content were measured using specific probes before and after the exposure and compared with unexposed other forearm as control. RESULTS: TEWL and pH of the exposed forearm increased significantly after 5 days of consecutive daily exposure to water. CONCLUSION: Water exposure increases the TEWL and pH of normal skin. Future studies evaluating the durability of the increased TEWL through monitoring the time course of events following skin immersion in water and susceptibility of skin to chemical irritants are required.