Haemangiomas can be indicators or clue signs for serious syndromes. Although less well known than those related to vascular malformations, there are some syndromes of important diagnostic value that are associated with haemangomias. Early recognition of problematic haemangiomas, together with a prompt intervention, may help to minimise their future morbidity. Neonatal haemangiomas warrant a special follow-up, since their growth pattern might be unpredictable at such an early age. Several clinical presentations are relevant because of their risk of syndromic association: cervicofacial haemangiomas, especially the extensive ones, may be markers for severe dysmorphic conditions like the PHACE(S) syndrome. Those distributed in the beard area are occasionally associated with haemangiomas of the airway. Lumbosacral haemangiomas usually hide an underlying spinal dysraphism or anorectal and urogenital anomalies. Multiple cutaneous haemangiomas may be a sign of visceral haemangiomatosis, most often hepatic, which becomes complicated by cardiac insufficiency or thyroid disease. Finally, there are two vascular neoplasms of rapid and invasive growth - kaposiform haemangioendothelioma and angioblastoma or tufted angioma - which, unlike infantile haemangioma, are markers for the Kasabach-Merritt syndrome.