A possibly irreversible process of hair loss is primary cicatricial alopecia, for which proper diagnosis of a skin biopsy is necessary. Looking out for new, non-invasive diagnostic approaches might shorten the period for final diagnosis, thus initiating the appropriate treatment and reduce the necessity for biopsy. The objective of this study was to assess the usefulness of high-frequency ultrasonography (HF-USG) as a diagnostic method in patients having primary scarring alopecia and also compare it with trichoscopy.

The study covered a total of 44adults, out of them 8 were with classic lichen planopilaris (LPP), 11 were with discoid lupus erythematosus (DLE), 14 were with frontal fibrosing alopecia (FFA), and 11 were healthy volunteers. Each patient had to undergo physical and trichoscopic examination that was the base for qualification for the active or inactive stage of the disease. The HF-USG was performed by using a probe having a frequency of 20 MHz. In HF-USG images, the following elements were assessed and measured: follicular structures (FS), entrance echo (EE), dermal/subdermal border (D/SB) and dermal background (DB).

The inactive phase was categorized by significantly lower number or lack of FS as compared to the active phase of scarring alopecia. HF-USG of active LPP/FFA had presented cigar-like shaped FS, whereas inactive stage had pronounced D/SB that formeda saw-like pattern. Active DLE in HF-USG were also associated with focal, doubled EE along with widened FS with aninclination to create hypoechogenic wide, structureless bands in the skin. In inactive DLE, no specific pattern of D/SB was formed or rarely a puzzle-like pattern was seen.

The study concluded that HF-USG images differ based on the phase of the disease process and the type of scarring alopecia, correspondingly to trichoscopic examination.

Source: Mikiel D, PolaÅ„ska A, Å»aba R, Adamski Z, DaÅ„czak-Pazdrowska A. Suitability of high-frequency ultrasonography (20 MHz) in evaluation of various forms of primary cicatricial alopecia in relation to trichoscopy - pilot study. Skin Res Technol. 2021 Mar 10. doi: 10.1111/srt.13018. Epub ahead of print. PMID: 33751668.