Blue rubber bleb nevus syndrome Symptoms & Causes

What is blue rubber bleb nevus syndrome?

Blue rubber bleb nevus syndrome (BRBNS) is a rare vascular anomaly in which malformed veins cause small, purple lesions—or blebs—on the skin and the surfaces of internal organs. In BRBNS, some of the child’s veins develop abnormally in the womb without all of the supporting smooth muscle layers normally seen in the vein walls. As a result, the veins become distended, allowing blood to pool in them. They also form as sponge-like masses instead of tubular conduits.


BRBNS is congenital (present at birth). The cause is not yet known, but researchers are actively searching for the condition's presumably genetic underpinnings.

Signs and symptoms

No two children experience blue rubber bleb nevus syndrome in exactly the same way. The main signs are the presence of small, purple, generally painless blebs on the skin. The blebs appear most frequently on the skin and in the gastrointestinal (GI) tract, but can be present just about anywhere on or in the body.

As a child gets older, more blebs may develop; they also tend to get larger over time. Some babies with the condition have blebs at birth that are too small to see. Sometimes the blebs stay small through childhood and flare slightly with the hormonal changes of puberty.

While the skin blebs rarely bleed, children with blebs in the GI tract can have frequent gastrointestinal bleeding caused by irritation of blebs by passing food or stool. In rare cases, these blebs can cause significant hemorrhaging.

Occasionally, a child will have a single dominant very large purple venous malformation. These can be often be removed surgically with great preparation and care.

Depending on how often and severe the bleeding is, patients may also complain of signs of anemia such as fatigue.