Intended for healthcare professionals

Practice Easily Missed?

Dermal sinus tracts

BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l5202 (Published 04 September 2019) Cite this as: BMJ 2019;366:l5202
  1. Mitchell T Foster, specialty trainee in neurosurgery1,
  2. Christopher A Moxon, clinical senior lecturer, honorary consultant in paediatric infectious diseases and immunology2 3,
  3. Elaine Weir, consultant paediatrician4,
  4. Ajay Sinha, consultant paediatric neurosurgeon1
  1. 1Department of Neurosurgery, Alder Hey NHS Foundation Trust, Liverpool L12 2AP, UK
  2. 2Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow
  3. 3Department of Paediatrics, Royal Hospital for Children, NHS Greater Glasgow and Clyde, Glasgow
  4. 4Department of Paediatric Medicine, Alder Hey NHS Foundation Trust, Liverpool
  1. Correspondence to: M T Foster mitchell.foster{at}doctors.org.uk

What you need to know

  • Consider dermal sinus tracts in patients presenting with any cutaneous markers overlying the dorsal midline spine, even if they are asymptomatic

  • MRI of the spine is optimal for diagnosis, but ultrasonography in neonates is quick to arrange and has a specificity of 98%

  • Undiagnosed, dermal sinus tracts can lead to progressive neurological deficits or serious infection such as meningitis

  • Dermal sinus tracts are different from innocuous coccygeal dimples, which are located lower within the gluteal cleft and are not associated with cutaneous stigmata; completely “classic” dimples do not require further workup or follow-up.

A newborn boy was noted to have a high-lying pit above the natal cleft with surrounding hair (fig 1). The family were reassured by their primary care doctor, and no further investigation was performed.

Fig 1

Photograph of patient’s lumbosacral region showing the small dermal sinus ostium in the sacral region with associated hair follicles. Given its low location, and the presence of only a small amount of hair, it is clear how this may have been mistaken for a benign coccygeal dimple. However, the associated cutaneous markers (hair follicles) and that the bottom of the lesion could not be clearly seen are the indicators that this is not an innocent lesion

At age 4 months, the boy presented with fever and vomiting to his local emergency department and was discharged with a diagnosis of suspected viral gastroenteritis. When he developed additional irritability, photophobia, and worsening pyrexia, lumbar puncture confirmed Escherichia coli meningitis, and the patient was started on intravenous antibiotics.

Clinical examination and magnetic resonance imaging (MRI) of the spine confirmed a lumbosacral dermal sinus tract with signs of associated infection of the cerebrospinal fluid (arachnoiditis around the cauda equina which had spread cranially, causing meningitis) (fig 2). After the infection had been treated with intravenous antibiotics, the …

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