Lesional skin of seborrheic dermatitis patients is characterized by skin barrier dysfunction and correlating alterations in the stratum corneum ceramide composition

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease characterized by erythematous papulosquamous lesions in sebum rich areas such as the face and scalp. Its pathogenesis appears multifactorial with a disbalanced immune system, Malassezia driven microbial involvement and skin barrier perturbations. Microbial involvement has been well described in SD, but skin barrier involvement remains to be properly elucidated. To determine whether barrier impairment is a critical factor of inflammation in SD alongside microbial dysbiosis, a cross-sectional study was performed in 37 patients with mild-to-moderate facial SD. Their lesional and non-lesional skin was comprehensively and non-invasively assessed with standardized 2D-photography, optical coherence tomography (OCT), microbial profiling including Malassezia species identification, functional skin barrier assessments and ceramide profiling. The presence of inflammation was established through significant increases in erythema, epidermal thickness, vascularization and superficial roughness in lesional skin compared to non-lesional skin. Lesional skin showed a perturbed skin barrier with an underlying skewed ceramide subclass composition, impaired chain elongation and increased chain unsaturation. Changes in ceramide composition correlated with barrier impairment indicating interdependency of the functional barrier and ceramide composition. Lesional skin showed significantly increased Staphylococcus and decreased Cutibacterium abundances but similar Malassezia abundances and mycobial composition compared to non-lesional skin. Principal component analysis highlighted barrier properties as main discriminating features. To conclude, SD is associated with skin barrier dysfunction and changes in the ceramide composition. No significant differences in the abundance of Malassezia were observed. Restoring the cutaneous barrier might be a valid therapeutic approach in the treatment of facial SD.

Reflectance Confocal Microscopy, Optical Coherence Tomography, and Multiphoton Microscopy in Inflammatory Skin Disease Diagnosis

BACKGROUND AND OBJECTIVES

Technological advances in medicine have brought about many novel skin imaging devices. This review aims to evaluate the scientific evidence supporting the use of noninvasive optical imaging techniques to aid in the diagnosis and prognosis of inflammatory skin diseases.

STUDY DESIGN/MATERIALS AND METHODS

PubMed and Scopus were searched in September 2020 according to PRISMA guidelines for articles using reflectance confocal microscopy (RCM), optical coherence tomography (OCT), and multiphoton microscopy (MPM) in inflammatory skin diseases, excluding studies monitoring treatment efficacy.

RESULTS

At the time of the study, there were 66 articles that addressed the utilization of noninvasive imaging in interface, spongiotic, psoriasiform, vesiculobullous, and fibrosing/sclerosing inflammatory skin dermatoses: RCM was utilized in 46, OCT in 16, and MPM in 5 articles. RCM was most investigated in psoriasiform dermatoses, whereas OCT and MPM were both most investigated in spongiotic dermatoses, including atopic dermatitis and allergic contact dermatitis.

CONCLUSIONS

There is preliminary evidence to support the diagnostic potential of noninvasive optical imaging techniques in inflammatory skin diseases. Improvements in the devices and further correlation with histology will help broaden their utility. Additional studies are needed to determine the parameters for diagnostic features, disease differentiation, and staging of inflammatory skin conditions. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Optical coherence tomography for patch test grading: A prospective study on its use for noninvasive diagnosis of allergic contact dermatitis

BACKGROUND

The diagnosis of allergic contact dermatitis should be confirmed by skin patch tests. Distinguishing between irritant and allergic reactions is sometimes difficult.

OBJECTIVES

To analyse the in vivo morphological changes in patch test reactions compared to healthy skin, and to detect subclinical changes in doubtful reactions using optical coherence tomography (OCT). To develop an OCT-based algorithm to support patch-test grading.

METHODS

One hundred twenty-nine skin patch-test areas were scanned with OCT to evaluate the following features: architectural and vascular morphology, epidermal thickness, optical attenuation coefficient (AC), and blood flow at 0.1, 0.2, and 0.35 mm depth.

RESULTS

Most common OCT features of acute contact allergic reactions in patch tests were spongiosis with microvesicles (94.8%), macrovesicles (60.3%), and coalescing vesicles (46.6%), the latter useful in differentiating acute allergic from irritant dermatitis (P-value < .05). Objective quantitative parameters correlated well with the severity grade: epidermal thickness due to spongiosis, AC (P-value < .05) and blood flow at 0.2 and 0.35 mm (P-value < .01).

CONCLUSIONS

OCT as a noninvasive diagnostic tool, established for skin cancer diagnosis, is useful for evaluating contact allergic patch-test reactions. Not only morphological but also objective features such as blood flow and AC correlate with the reaction severity. Further studies are needed to explore the differences in irritant and allergic contact dermatitis.

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.

Chromametric assessment of drug skin tolerance: A comparative study between Africans and Caucasians skins

BACKGROUND/AIMS

During dermatological forms development, one of the simplest non-invasive techniques used to evaluate cutaneous tolerance of formulations is to monitor the color changes using a tristimulus chromameter. Most published tolerance studies involving chromametric measurements are performed on Caucasian subjects. However, in the context of drug formulation for African-type populations, it is not always relevant to transpose tolerance results obtained on Caucasians populations to African-type ones due to histological ethnic differences of the skin. The goal of this work was to assess whether tristimulus chromameter can be used to highlight color variations following the application of dermatological topics on black skin in order to validate skin tolerance studies made on African-type subjects.

MATERIALS AND METHODS

After application of two commercial creams with opposite side effects (skin irritation and skin blanching) in both Africans and Caucasians populations, color variations were evaluated using a tristimulus chromameter in L^* a^* b^* color system and compared between both populations. L^* indicating color brightness, a^* represents green and red directions and b^* represents blue and yellow directions.

RESULTS

While skin irritation resulted in a significant increase of a^* parameter in both studied populations, the skin blanching resulted in a decrease of a^* associated with an increase of L^* .

CONCLUSION

We established that tristimulus chromameter can be used to achieve in vivo skin tolerance study of dermatologic formulations in Africans despite their dark skin even though it appeared less sensitive. This study can speed up the development of dermatological forms dedicated to Africans and/or Caucasians subjects.