• Port-Wine Stain Birthmark (Nevus Flammeus): This is the most common and often the first visible sign of SWS. It is a flat, pink to deep purple birthmark caused by an overgrowth of capillaries near the skin’s surface. It usually appears on one side of the face, often involving the forehead and upper eyelid, in the distribution of the trigeminal nerve. The skin within the birthmark can darken and thicken over time.
• Leptomeningeal Angioma: These are abnormal blood vessels that form in the meninges, the delicate membranes covering the brain and spinal cord, on the same side of the head as the facial birthmark. These angiomas can impair blood flow to parts of the brain, leading to:-
  • Seizures: Often the first neurological manifestation, typically beginning in infancy and potentially worsening with age. Seizures are usually focal (affecting one side of the body, opposite the birthmark).
  • Stroke-like episodes: Causing temporary muscle weakness on one side of the body (hemiparesis), vision abnormalities, and headaches.
  • Developmental delays and cognitive impairment: Ranging from mild learning difficulties to severe intellectual disability, depending on the extent and location of brain involvement. Earlier onset of seizures is often associated with a higher risk of developmental delays.
  • Headaches: Including migraines, often related to vascular issues.
• Glaucoma: Increased pressure within the eye due to fluid buildup. This typically affects the eye on the same side as the facial birthmark and can lead to eye enlargement (buphthalmos) in infants, and potentially vision loss if untreated.

Other possible symptoms include:-

• Eye enlargement (buphthalmos)
• Visual field defects or blindness
• Endocrine irregularities
• Early handedness or gaze preferences in infants