Line-field confocal optical coherence tomography in lichen planopilaris and frontal fibrosing alopecia: A pilot study

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are common causes of cicatricial alopecia. While several studies have demonstrated the usefulness of non-invasive imaging methods such as reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) for the diagnosis of scarring alopecia, this study aimed to identify characteristic features of cicatricial alopecia in LPP/FFA using line-field confocal OCT (LC-OCT).

Fifty-one patients (26 LPP, 24 FFA, 1 LPP and FFA) were prospectively analyzed with LC-OCT at three defined locations on the scalp: (1) scarring area = lesion, (2) scar-hair boundary = transition zone and (3) healthy area for the presence of the following pre-defined criteria: no hair follicles left, destructed hair follicles, dermal sclerosis, no rimming of the dermal papillae, epidermal and dermal inflammatory infiltrate, infundibular hyperkeratosis, dilated blood vessels, hypervascularization, melanophages, epidermal pigment incontinence.

Comparison of the transition zone with healthy control sites revealed the four main LC-OCT features in LPP/FFA: dermal sclerosis (100%), dermal inflammatory infiltrate (90.2%), infundibular hyperkeratosis (60.8%) and hypervascularization (76.5%).

LC-OCT detects specific criteria of pathological changes in LPP/FFA around hair follicles in the epidermis and dermis and therefore can be used for further studies investigating scarring alopecia.