Congenital dermal sinus may form at any point along the midline of the neuraxis, however, the majority form in the lumbar and lumbosacral region (41% and 35% of cases respectively). Diagnosis
Congenital dermal sinus is often diagnosed in infants and children. Early diagnosis is important in congenital dermal sinus, so that treatment can be provided early, to prevent progression of associated complications. Clinical features
There three key hallmarks of congenital dermal sinus: cutaneous abnormalities, infection, and neurological deficits. Cutaneous abnormalities
Congenital dermal sinus is a tract from the surface layer of the skin, through the deeper tissues into the cranial or spinal cavity. The skin findings of this tract can include:

Pit along neuraxis
Flat capillary hemangioma
Hypertrichosis
Skin tag
Abnormal pigmentation
Subcutaneous lipoma
Signs of local infection

Infection
The stratified squamous epithelium of the congenital dermal sinus tract can extend to the spinal fascia of the dura mater or all the way to the spinal cord. Thus, the congenital dermal sinus forms a point of entry for infection, this can allow for the formation of an abscess, especially among children. Infection can then travel up the spinal cord to result in meningitis, which can be fatal if left untreated. Neurological deficit
Congenital dermal sinus is often also associated with spinal fluid drainage, intradural cysts and spinal cord tethering; conveying neurological deficit. Neurological deficit can occur due to spinal cord compression from intradural dermoid cyst growth in the epidermis and dermis. Tethered spinal cord can result in gait difficulties and sphincter dysfunction, as well as compressing the spine.
Causes
Disorders that cause, or increase the risk for systemic venous thrombosis are associated with central venous thromboses. In children, head and neck infections and acute systemic illnesses are the primary cause of central venous thrombosis. Cerebral venous sinus thrombosis is more common in particular situations. 85% of people have at least one of these risk factors:
Thrombophilia, a tendency to develop blood clots due to abnormalities in coagulation, e.g. factor V Leiden, deficiency of protein C, protein S or antithrombin, or related problems
Nephrotic syndrome, a kidney problem causing protein loss in the urine
Chronic inflammatory diseases, such as inflammatory bowel disease, lupus and Behçets disease
Pregnancy and puerperium (the period after giving birth)
Particular blood disorders, especially polycythemia vera and paroxysmal nocturnal hemoglobinuria
Use of estrogen-containing forms of hormonal contraception
Meningitis and infections of the ear, nose and throat area such as mastoiditis and sinusitis
Direct injury to the venous sinuses
Medical procedures in the head and neck area
Obesity, especially in combination with oral contraceptive use 
Sickle cell anemia
Dehydration, primarily in infants and children
Homocysteinemia
Homocystinuria

Diagnosis
The diagnosis may be suspected on the basis of the symptoms, for example the combination of headache, signs of raised intracranial pressure and focal neurological abnormalities, or when alternative causes of headache and neurological abnormalities, such as a subarachnoid hemorrhage, have been excluded. Imaging
There are various neuroimaging investigations that may detect cerebral sinus thrombosis.