[Skin markers of communicating dermal sinus: report of two cases]

Skin abnormalities in the spinal lumbosacral region of infants are not infrequent. Physicians should look for underlying spinal malformations. We report 2 cases of dermal sinus in infants revealed by severe, acute meningitis. The dermal sinus is an abnormal tract between the skin and underlying neural structures, most often located in the lumbosacral region. It may end blindly in the subcutaneous tissues, or it may extend into the medullary space. The diagnosis should be suspected in patients with other skin findings: localized hypertrichosis, subcutaneous lipomas, hyperpigmented lesions, etc. It must be distinguished from the very frequent coccygeal pits (4% of newborns), which require no treatment. Magnetic resonance imaging should be done every time the diagnosis is suspected. Recurrent bacterial meningitis or meningitis caused by unusual bacteria is frequently associated with dermal sinus. A variety of neurologic abnormalities have been described: sensory changes, motor weakness, reflex changes, abnormal bowel and bladder function, etc. Infants generally have few neurologic symptoms, such as delayed walking or sphincter control. Orthopaedic abnormalities are rare. The dermal sinus tract needs to be detected at an early stage in order to avoid these complications, which can be prevented by early surgery.