Background Subungual haemorrhages are characterized by well-circumscribed dots or blotches with a red to red-black pigmentation, but some cases can be difficult to distinguish from subungual melanoma by the naked eye alone. Dermoscopy has proven to be a useful, noninvasive tool in the diagnosis of pigmented lesions in the nail; however, few dermoscopic studies of subungual haemorrhages have been reported. Objectives To investigate characteristic dermoscopic patterns of subungual haemorrhages, and to find distinctive features that can differentiate them from nail-unit melanomas. Methods Patients with a confirmed diagnosis of either subungual haemorrhage or nail-unit melanoma at a tertiary university hospital were included in the study. Clinical features and dermoscopic patterns were evaluated. Results Sixty-four patients with a total of 90 lesions of subungual haemorrhage were enrolled in the study. The majority of cases (84%) showed combinations of more than one colour, while 16% had only one colour. The most common colour of the subungual haemorrhages was purple-black, in 37% of cases. A homogeneous pattern was observed in 92% of cases, globular patterns in 42% and streaks in 39%. Peripheral fading and periungual haemorrhages were found in 54% and 22% of cases, respectively. Destruction or dystrophy of the nail plate was observed in 16% of cases. In the 16 cases of nail-unit melanomas, Hutchinson sign, longitudinal irregular bands or lines, triangular shape of bands, vascular pattern, and ulcerations were found in 100%, 81%, 25%, 6% and 81% of cases, respectively. In contrast, these features were not found in subungual haemorrhages. Conclusions Dermoscopy provides valuable information for the diagnosis of subungual haemorrhage and aids in the differential diagnosis from nail-unit melanoma. What's already known about this topic? Subungual haemorrhage is a common imitator of subungual melanoma, and thus subungual melanoma should always be included in the differential diagnosis of subungual haemorrhage. Dermoscopy is a helpful, noninvasive diagnostic tool that has been reported to improve diagnostic accuracy in pigmented nail lesions. What does this study add? The results of our study show that the characteristic dermoscopic findings of subungual haemorrhage can be summarized as homogeneous patterns, globular patterns, streaks, peripheral fading and periungual haemorrhages. This study shows that dermoscopy provides valuable information for the diagnosis of subungual haemorrhages and assists in its differential diagnosis from nail-unit melanomas.