Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(2):e2024132 1 The “Watch Sign” – Another Observation in the Course of Male Frontal Fibrosing Alopecia Jakub Żółkiewicz1, Urszula Maińska1, Roman J. Nowicki1, Michał Sobjanek1, Martyna Sławińska1 1 Department of Dermatology, Venereology and Allergology, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland Key words: frontal fibrosing alopecia, cicatricial alopecia, watch sign, trichoscopy, Renbök phenomenon Citation: Żółkiewicz J, Maińska U, Nowicki RJ, Sobjanek M, Sławińska M. The “Watch Sign” – Another Observation in the Course of Male Frontal Fibrosing Alopecia. Dermatol Pract Concept. 2024;14(2):e2024132. DOI: https://doi.org/10.5826/dpc.1402a132 Accepted: December 13, 2023; Published: April 2024 Copyright: ©2024 Żółkiewicz et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Martyna Sławińska MD, PhD, Department of Dermatology, Venereology and Allergology, Faculty of Medicine, Medical University of Gdańsk, Smoluchowskiego 17 Street, 80-214 Gdańsk, Poland. Tel. +48585844014; fax +48585844010. E-mail: martyna.slawinska@gumed.edu.pl Introduction Recently, Barreto et al. described a new clinical observation in frontal fibrosing alopecia (FFA) − the “watch sign” [1]. The authors described two males in whom, despite involve- ment of forearms, hair loss spared the area regularly covered by a wristwatch. Herein we present two additional male FFA patients at- tending our dermatology outpatient clinic screened for this novel sign. Case presentation The first patient was a 79-year-old male (phototype I) ad- mitted for surgical treatment of basal cell carcinoma. Apart from the tumor, advanced recession of the hairline to the border of  the parietal and occipital area of the scalp was observed (Figures 1a, 1d). In addition, clinical features of madarosis as well as loss of hair on the upper extremities were noted (Figures 1b, 1c, 1e). The patient had neither been diagnosed nor treated for FFA before. Dermoscopic evalua- tion of the left arm, just under the area usually occupied by his analogue watch, revealed preserved hairs, corresponding with the “watch sign” (Figures 1c, 1f). The second patient was a 30-year-old male (phototype II) treated for FFA in a dermatology outpatient clinic for two years. On clinical examination, minor recession of frontotemporal hairline with erythema and accompany- ing madarosis were observed (Figures 2a, 2b, 2d, 2e). The patient had previously been treated with topical cortico- steroids, isotretinoin, triamcinolone acetonide mesother- apy, and oral minoxidil. Additionally, bimatoprost and tacrolimus were applied on the eyebrow area. The patient reported wearing a smartwatch on his left wrist on a daily basis. However, forearms were not affected by the disease, and dermoscopy did not reveal differences in hair density and structure in corresponding wrist areas on both sides (Figures 2c, 2f). 2 Research Letter | Dermatol Pract Concept. 2024;14(2):e2024132 Figure 1. Clinical and trichoscopic images of the first described patient diagnosed with FFA. (a, b) Severe hair loss, with significant recession of frontotemporal hairline and partial loss of eyebrows; (c) Three terminal hairs arising on the left forearm; (d, e) Corresponding trichoscopy of scalp and eyebrows, respectively; (f) Trichoscopy of the “watch sign” on the left forearm revealed preserved hairs with mild perifollicular scaling. FotoFinder, Medicam 800 HD, 70x magnification, immersion gel Figure 2. Clinical and trichoscopic images of a second FFA patient. (a) Cicatricial band of frontal hairline recession with extensive perifol- licular erythema. The “lonely hair” sign is also clinically visible; (b) Almost complete loss of the eyebrows; (c) Symmetrical hair distribution on both forearms, with no discernible “watch sign” (L, R – left and right forearm, respectively); (d) Trichoscopy of frontal hairline shows loss of vellus hairs and follicular openings, ivory background, perifollicular erythema, scaling, and pili torti; (e) Mild perifollicular scale is visible on eyebrow trichoscopy. Multiple yellow dots and focal erythema are also notable. (f) Trichoscopy of the left forearm does not show any clue for FFA diagnosis. FotoFinder, Medicam 800 HD, 70x magnification, immersion gel Research Letter | Dermatol Pract Concept. 2024;14(2):e2024132 3 Conclusion FFA is a distinct clinical subset of lichen planopilaris which causes permanent hair loss due to inflammation and sub- sequent scarring. Underlying factors triggering the devel- opment of FFA remain unknown. Typically, FFA initially manifests with progressive recession of the frontotemporal hairline, usually accompanied by perifollicular erythema and scaling. Furthermore, most patients experience complete or partial loss of the eyebrows, although non-glabrous skin in any location may be affected. FFA predominantly affects postmenopausal women. Fewer than 2% of FFA patients are males [2]. In contrast to the previous report, only one of the two male patients from our department presented the “watch sign”. The underlying pathomechanism of this finding re- mains unknown. Barreto et al. [1] in their report presented convincing exclusionary arguments concerning the possible association with sun exposure, sunscreen, moisturizer, or other cosmetic products [3, 4]. The authors suggested a mechanism related to the Ren- bök phenomenon. Previously, this phenomenon had been reported in the context of FFA sparing dermal melanocytic nevus and vascular nevus [5, 6]. In the case of “the watch sign,” it could be related to pathological processes in the skin induced by pressure or temperature increase associated with the use of a wristwatch. Our observation supports the occurrence of the “watch sign” in males with FFA who wear a wristwatch. Further studies on the “watch sign” may bring new insights into dis- ease pathogenesis. References 1. Barreto TM, Cortez de Almeida RF, Muller Ramos P, Jeunon T, Melo DF. The watch sign: an atypical clinical finding of frontal fibrosing alopecia in two male patients. J Eur Acad Dermatol Venereol. 2022 Jun;36(6):e437-e9. DOI: 10.1111/jdv.17934. PMID: 35034396. 2. Starace M, Orlando G, Iorizzo M, et al. Clinical and Dermoscopic Approaches to Diagnosis of Frontal Fibrosing Alopecia: Results From a Multicenter Study of the International Dermoscopy So- ciety. Dermatol Pract Concept. 2022 Feb;12(1):e2022080. DOI: 10.5826/dpc.1201a80. PMID: 35223189. 3. 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