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Clinical and Dermoscopic Features of Subungual Hemorrhage: A Retrospective Study of 420 Cases.

Wu Xiaoting X, Lin Zhaoping Z, Shen Xue X, Wang Jieyi J et al.

Subungual hemorrhage (SH) may be difficult to distinguish from nail unit melanoma, onychomycosis, and other nail disorders. Dermoscopy enables non-invasive visualization of subtle subungual structures and provides useful information for differential diagnosis. This study aimed to analyze the clinical and dermoscopic features of SH and explore their associations with lesion location, disease course, and nail involvement. Clinical and dermoscopic data of 420 patients diagnosed with SH between December 2018 and March 2024 were retrospectively collected from two tertiary hospitals in China. Patients aged 18-45 years accounted for 65.5% of the cohort, and 84.3% of lesions were located on the toenails. Most patients (69.5%) had a single lesion, and 73.8% and 79.3% showed no nail margin involvement or nail plate damage, respectively. Toenail involvement was more frequent in female (p = 0.003) and young adult (p = 0.002) patients. The predominant dermoscopic features were purplish-red/black pigmentation (72.9%), irregular morphology (71.0%), and linear or striated pseudopods surrounding the lesion (56.7%). Irregular morphology was significantly more frequent in toenail lesions, whereas linear morphology was more common in fingernail lesions (both p < 0.001). Irregular shapes were predominant (73.6%) in cases with a short-term course (< 3 months), whereas linear lesions accounted for 31.6% of lesions in patients with a long disease course (≥ 12 months). Lesion morphology was significantly associated with disease course (p < 0.001). Irregular morphology was also significantly associated with nail margin involvement (p < 0.001) and nail plate damage (p = 0.007), while linear or striated pseudopod lesions showed a significant association with nail margin involvement (p < 0.001). In this cohort, SH predominantly affected females and young adults and typically presented as a single toenail lesion. Dermoscopic features of SH varied according to lesion location and disease course, and irregular morphology was associated with nail margin involvement and nail plate damage. Recognition of characteristic dermoscopic features, together with clinical history and lesion evolution, may facilitate differentiation of SH from nail unit melanoma and other nail disorders, help avoid unnecessary biopsy in typical cases, and prompt further evaluation of suspicious lesions.

Baricitinib response pattern by baseline nail involvement in children under 12 with alopecia areata.

Zhang Xinyi X, Wang Qin Q, Tao Ke K, Lin Jui-Ming JM et al.

Reimagining nail health: The next frontier in dermatologic innovation.

Ishack Stephanie S, Garibyan Lilit L

Nail disorders are a frequently overlooked aspect of dermatology despite their effects on function, appearance, and QOL. Although artificial intelligence (AI)-driven skin analysis tools have advanced rapidly for acne, pigmentation, lesion classification, and melanoma risk assessment, the nail unit remains underrepresented in validated digital dermatology platforms. This gap limits early diagnosis, objective monitoring, and treatment assessment for conditions including onychomycosis, nail psoriasis, longitudinal melanonychia, and traumatic nail dystrophies. This review examines current AI-enabled dermatology platforms, identifies gaps in nail assessment, and proposes a framework for future nail-focused computational imaging. Published studies and publicly available platforms were evaluated for imaging methods, analytic capabilities, validation, and clinical relevance. Skin-focused AI systems demonstrate image analysis techniques applicable to nail disease, yet most consumer nail applications remain cosmetic. Emerging studies support the feasibility of AI-assisted nail imaging, but they are limited by small datasets, retrospective designs, limited external validation, and underrepresentation of diverse skin tones and nail morphologies. Standardized nail photography, expert-annotated datasets, explainable AI, prospective validation, and teledermatology integration are needed to translate AI-assisted nail assessment into clinically useful tools and advance precision digital dermatology.

Beyond Melanoma: Hutchinson's Sign in Subungual Melanocytic Activation - A Case Report.

Al Muqrrab Fatimah J FJ, Alhumidi Ahmed A, Al-Haddab Mohammed M

Hutchinson's sign, defined as periungual pigmentation extending into the surrounding nail folds, is conventionally considered a hallmark of subungual melanoma. However, several benign nail disorders may present with Hutchinson's sign, creating a diagnostic challenge for clinicians. We report the case of a 33-year-old Saudi man who developed a progressive brown-black longitudinal band on his left little fingernail accompanied by pigmentation extending into the eponychium. Dermoscopy revealed irregularly spaced parallel lines with brush-like extensions in the proximal nail fold. Given the clinical suspicion of nail melanoma, a tangential nail matrix biopsy was performed. Histopathology demonstrated increased basal melanin deposition with cytologically bland melanocytes, which is consistent with subungual melanocytic activation. The patient was followed for 6 months. The nail completely regrew with no dystrophy, and the band had recurred. This case highlights that Hutchinson's sign is not pathognomonic for melanoma and can occur in benign entities such as subungual melanosis. Careful integration of clinical, dermoscopic, and histopathological findings is essential for accurate diagnosis, avoiding unnecessary aggressive interventions while ensuring patient safety.