The hair collar sign

Abstract

We report on two children with congenital scalp lesions which were surrounded by a ring of dark hair known as a hair collar. A review of previously reported patients with hair collars revealed that most of the scalp lesions were single and located at the vertex or parietal areas. They were most commonly composed of heterotopic neural tissue. We found a significant risk of associated skull defects, direct connections to the central nervous system (CNS), and brain and cerebrovascular anomalies in these patients. Careful clinical evaluation and MRI of the brain are indicated prior to biopsy or excision of these scalp lesions.

The histopathological spectrum of cutaneous meningeal heterotopias: clues and pitfalls

“…It was not clear, however, due to the retrospective methodology of our study, whether a ‘hair collar’, i.e. overgrown hyperpigmented hair surrounding the central zone of alopecia, was present or not in many of our patients 18–23 …”

“…overgrown hyperpigmented hair surrounding the central zone of alopecia, was present or not in many of our patients. [18][19][20][21][22][23] The lesions were distributed on the skin overlying the neuraxis, most of them on the scalp, with a predilection for the parieto-occipital region. Scalp lesions were often outside the midline, perhaps overlying sutures of the cranium.…”

The hair collar sign – a possible indication of cranial dysraphism

“…When an alopecic lesion surrounded by a hair collar is present, cranial imaging should be performed. This diagnostic measure is particularly relevant before planned biopsies or excisions [6].…”

Aplasia cutis congenita: Evaluation of signs suggesting extracutaneous involvement

“…Findings from prior case reports suggest that the majority of cases of ACC occur as isolated cutaneous lesions, but nodules, midline lesions on the vertex, hair collar sign, and larger lesions have all been reported as warranting further investigation for underlying central nervous system (CNS) defects. Similar to previous reports, the results of our study confirmed the importance of clinical clues in suggesting scalp involvement . These clinical indicators include the hair collar sign, midline vertex location, size greater than 5 cm, vascular stains, and nodules.…”