Optical Coherence Tomography Distinguishes Between Different Inflammatory Scalp Disorders

Seborrheic dermatitis, which is one of the most common skin manifestations of HIV, has been reported in 85% to 95% of people positive for HIV vs 3% to 5% of uninfected persons.7 Its etiology remains unknown, but it most commonly manifests when CD4 counts drop to ≤550 cells/µL and worsens with CD4 count declines, making it a useful marker of disease progression.2,7 Risk is also increased in men, individuals with oily skin, and in climates with cold, dry winter air.7 Recurrences are common and stress can trigger a flare-up.8 Seborrheic dermatitis is characterized by itchy reddish or pink patches of skin with concomitant greasy-looking white or yellowish flakes or scales.8 It typically affects the scalp and face, but may also involve the ears, chest, upper back, axillae, and groin.8
Optical coherence tomography is a less invasive method that can aid in the diagnosis of inflammatory scalp disorders, especially those with overlapping symptoms.

Optical coherence tomography (OCT) is a noninvasive imaging approach that can accurately identify features of and distinguish between different types of inflammatory scalp disorders, according to study research that appeared in the Journal of the European Academy of Dermatology and Venereology.

Adult patients with biopsy-proven seborrheic dermatitis (n=4), psoriasis (n=5), or contact dermatitis (n=3) were enrolled from an outpatient dermatology clinic of the University of Miami Hospital. Another 2 healthy volunteers were included in the study as controls. Images were taken of regions of the scalp with trichoscopy-identified active disease. Both dynamic OCT scans and trichoscopy images were taken of the frontal area and were compared with those of a healthy scalp.

Imaging of seborrheic dermatitis with dynamic OCT indicated a vasculature transition from the superficial to the deep plexus. Small dilated vessels that alternated with thinner arborizing vessels were revealed from en face images of the superficial plexus. In addition, en face imaging of the deep plexus showed dilated arborizing and “lava-like” vessels that were organized in a net-like configuration.

In contact dermatitis, dynamic OCT revealed organized large-caliber vessels in an irregular network in en face imaging of the superficial plexus. Compared with controls, imaging analysis of the cross-sectional view of the scalp showed a higher attenuation coefficient, suggesting greater unevenness on the surface of the skin.

In the scalps of patients with psoriasis, a scattered pattern of spindle-like glomerular vascular dilations were revealed with the en face imaging of dermal papillae. Healthy skin consistently contains more regularly distributed, thin capillaries. Compared with controls, the network of dilated spiral vessels in the scalps with psoriasis was denser. Increased epidermal thickness was also demonstrated in the cross-sectional image analysis.

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In a healthy scalp, the dynamic OCT of the superficial plexus revealed dermal papillae capillaries that demonstrated dotted, homogeneous, and well-organized interfollicular patterns. Vessels remained well organized and large at the deeper subpapillary vascular plexus upon OCT imaging.

Limitations of the study include the small number of participants and the lack of blinding of investigators.

The researchers of this study suggest “cost, training and limited availability are the major barrier on use of dynamic OCT in the clinical setting.”

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Reference

Rajabi-Estarabadi A, Vasquez-Herrera NE, Martinez-Velasco MA, et al. Optical coherence tomography in diagnosis of inflammatory scalp disorders [published online February 20, 2020]. J Eur Acad Dermatol Venereol. doi: 10.1111/jdv.16304