Line‐field confocal optical coherence tomography: a new tool for non‐invasive differential diagnosis of pustular skin disorders

Abstract

Background The spectrum of pustular skin disorders (PSD) is large and particularly challenging, including inflammatory, infectious and amicrobial diseases. Moreover, although pustules represent the unifying clinical feature, they can be absent or not fully developed in the early stage of the disease. The line-field confocal optical coherence tomography (LC-OCT) is a recently developed imaging technique able to perform a non-invasive, in vivo, examination of the epidermis and upper dermis, reaching very high image resolution and virtual histology.Objectives We aimed to investigate the potentialities of LC-OCT in the non-invasive differential diagnosis of a series of 11 PSD with different aetiology, microscopic features, body location and incidence rates. Materials and MethodsComplete LC-OCT imaging (i.e. 2D/3D frames, videos) was performed on a total of 19 patients (10 females and 9 males) aged between 35 and 79 years. Images were blindly evaluated and compared with corresponding histopathologic findings. ResultsThe LC-OCT imaging was able to detect with high accuracy the pustule structure including shape, margins, morphology and cellular content, along with peculiar epidermal and adnexal alterations in each condition, including: Acute Generalized Exanthematous Pustulosis, Generalized pustular psoriasis, Generalized pustular figurate erythema, Subcorneal Pustular Dermatosis, Intraepidermal IgA pustulosis, Palmoplantar pustulosis, Palmoplantar pustular psoriasis. Herpetic whitlow, Acrodermatitis continua of Hallopeau, Vesicopustular Sweet syndrome and Vesicopustular Eosinophilic cellulitis, with pustular appearance, were also compared. ConclusionsThe new LC-OCT can represent a rapid, non-invasive and painless tool which can help differentiating among PSD of different aetiology and microscopic morphology in clinical mimickers in daily practice.

Authors' reply to: ‘Generalized pustular figurate erythema first report in two COVID‐19 patients on hydroxychloroquine’

“…Dermoscopy 30x performed both on the pustule margin (Figures 1d and 2d ) and on lesional skin near the pustule (Figure 1f ) revealed numerous bright red curved vessels and clods 2 corresponding to dilated capillaries in dermal papillae. 9 …”

“…To the best of our knowledge, this is the first description of GPFE dermoscopic features. The identification of those dermoscopic clues—that is tiny pustule surrounded an erythematous halo with evident curved vessels and clods—can be of help in recognizing GPFE cases presenting in late phase and/or modified by corticosteroid treatment 9 and in differentiating them from a variety of forms which can exhibit overlapping features, including erythema multiforme, AGEP, prolonged/recalcitrant AGEP, AGEP/SJS overlap and generalized annular pustular psoriasis. 3 , 4 , 5 , 6 , 7 , 8 Indeed, in erythema multiforme the clods are reddish‐purple in the central dusky zone and reddish in the outer red ring, with linear vessels at the periphery; in AGEP, no distinct vessels are visible around the millimetric pustules; in generalized annular pustular psoriasis the pustules are surrounded by regularly distributed dotted vessels.…”

Automatic Segmentation of Laser-Induced Injury OCT Images Based on a Deep Neural Network Model

“…However, the tissue regeneration was evaluated only according to the color morphology in the observed image, and the damaged part was not segmented. Line field confocal optical coherence tomography (LC-OCT) imaging can detect pustular structures with high accuracy, including shape, edge, morphology, and cell content, as well as unique epidermal and accessory changes in different cases [ 27 ]. Kavita Dubey et al detected human skin thermal injury based on a classifier by separating the morphological features extracted from polarization-sensitive optical coherence tomography (PS-OCT) images and achieved good results [ 28 ].…”

Rapid Cellular-Resolution Skin Imaging with Optical Coherence Tomography Using All-Glass Multifocal Metasurfaces

“…This tool can enable the diagnosis of more subtle skin conditions such as cutaneous autoimmune diseases, eczematous conditions, or melanocytic neoplasms which require higher magnification with cellular resolution for diagnosis. 19 More generally, this multifocal metasurface platform demonstrates promising applications across a broad range of microscopic systems, including confocal, 20 multiphoton, 21 and photoacoustic imaging, 22 where it is able to significantly increase the volumetric imaging speed while maintaining identical 3D spatial resolution.…”