Trichoscopic signs of tinea capitis: a guide for selection of appropriate antifungal

Abstract

Background Tinea capitis is the most common pediatric dermatophyte infection. Optimal treatment regimen differs according to the type of the dermatophyte involved. Objectives The aim of this work was to study the trichoscopic signs in relation to isolated organism in a sample of Egyptian patients with tinea capitis and the possibility of using them as a guide for selection of appropriate antifungal. Methods This study was carried out on 60 subjects with tinea capitis. Patients were mycologically examined, both direct microscopy with KOH preparation and culture of the scraped hair materials on Sabouraud dextrose agar. Culture mounts were used for identification of the organism. Trichoscopic examination of all patients was performed using the Dermlite DLIII dermoscope. Results There was significant higher prevalence of both comma and corkscrew hair in endothrix infection and T. violaceum‐infected cases. On the other hand, there was significant higher prevalence of zigzag, barcode hairs, and white sheaths in ectothrix infection and M. canis‐infected cases. Conclusion While some trichoscopic findings are nonspecific, others were found to be more specific. Finding zigzag hairs and barcode hairs points to ectothrix infection (M. canis), and it is recommended to start treatment with griseofulvin. On the other hand, finding comma hairs and corkscrew hairs without zigzag hairs and barcode hairs points to endothrix infection (T. violaceum), and it is recommended to start treatment with terbinafine in the usual dose.

Tinea Capitis by Microsporum canis in an Elderly Female with Extensive Dermatophyte Infection

“…Common dermoscopic findings may involve broken hairs, scales, black dots, perifollicular erythema, comma hairs, empty follicles and pustules [ 11 ]. In ectothrix infection caused by M.canis , Morse code-like hairs (AKA barcode-like hairs) [ 19 , 20 ] and white sheaths [ 21 , 22 ] are typical characteristics under the dermoscope. For a definitive diagnosis, mycological examinations are very important.…”

Tinea capitis: An update

“…which cause endothrix infections do not fluoresce. 5 The practice of trichoscopy has increased in popularity as this technique is simple, non-invasive, and relatively inexpensive. While trichoscopy can reveal features associated with endothrix and ectothrix infections (such as barcode, corkscrew, and comma hairs), which may allow a practitioner to decide on an antifungal regimen, it does not allow for dermatophyte identification at either the genus or species level.…”

“…While trichoscopy can reveal features associated with endothrix and ectothrix infections (such as barcode, corkscrew, and comma hairs), which may allow a practitioner to decide on an antifungal regimen, it does not allow for dermatophyte identification at either the genus or species level. 5 Nonetheless, trichoscopy is a useful test for distinguishing between dermatophyte infections and other causes of hair abnormalities, including alopecia areata and trichotillomania. Given that prolonged systemic therapy is required, and other disorders such as seborrheic dermatitis, psoriasis, trichotillomania, and alopecia areata are possibilities, the authors recommend utilising all available diagnostic tools to confirm the presence of fungal infection.…”

“…The practice of trichoscopy has increased in popularity as this technique is simple, non‐invasive, and relatively inexpensive. While trichoscopy can reveal features associated with endothrix and ectothrix infections (such as barcode, corkscrew, and comma hairs), which may allow a practitioner to decide on an antifungal regimen, it does not allow for dermatophyte identification at either the genus or species level 5 . Nonetheless, trichoscopy is a useful test for distinguishing between dermatophyte infections and other causes of hair abnormalities, including alopecia areata and trichotillomania.…”

Giá Trị Của Dermoscopy Trong Chẩn Đoán Nấm Da Đầu

“…Độ nhạy của các dấu hiệu này từ 22,6-83%, độ đặc hiệu cao 87,2-100%, giá trị dự báo dương tính 85,3-100%, giá trị dự báo âm tính 52,3-82% [6]. Genedy và cộng sự (2021) thực hiện phân tích trên 60 bệnh nhân Ai Cập cho thấy hình thái lâm sàng hay gặp nhất là mảng rụng tóc chiếm 73,3%, tỷ lệ nuôi cấy dương tính là 90%, các dấu hiệu trên dermoscopy hay gặp là vảy da lan toả (96,7%), tóc gãy (90%), vảy da quanh chân tóc (85%), tóc hình dấu phẩy (73,3%), tóc hình xoắn nút chai (68,3%), và vỏ bọc trắng gần da đầu (50%) [5]. Độ nhạy của tóc hình dấu phẩy là 93,33%, độ đặc hiệu 87,5% với nhiễm khuẩn nội sợi và giá trị dự đoán dương tính là 97,67%.…”