Red birthmarks are colored, vascular (blood vessel) skin markings that develop before or shortly after birth.

There are two main categories of birthmarks. Red birthmarks are made up of blood vessels close to the skin surface, and are called vascular birthmarks. Pigmented birthmarks are areas in which the color of the birthmark is different from the color of the rest of the skin.

Hemangiomas are a common vascular birthmark. They are usually painless and harmless. The cause of hemangioma is unknown. The color results from the extensive development of blood vessels at the site.

Strawberry hemangiomas (strawberry mark, nevus vascularis, capillary hemangioma, hemangioma simplex) may appear anywhere on the body, but are most common on the face, scalp, back, or chest. They consist of small, closely packed blood vessels. They may be absent at birth, and develop at several weeks. They usually grow rapidly, remain a fixed size, and then subside. Ninety-five percent of strawberry hemangiomas disappear by the time the child is 9 years old, although there may be some slight discoloration or puckering of the skin where a strawberry hemangioma existed.

Cavernous hemangiomas (angioma cavernosum, cavernoma) are similar to strawberry hemangiomas but are more deeply situated. They may appear as a red-blue spongy mass of tissue filled with blood. Some of these lesions disappear on their own, usually as a child approaches school age.

A port-wine stain is a flat hemangioma made of dilated blood capillaries. The face is the most common location. The size varies from very small to over half of the body surface. This is often a permanent defect, sometimes causing significant emotional distress. Port wine stains on the face may be associated with Sturge-Weber syndrome.

Salmon patches (stork bites) are small, pink, flat spots. They are extremely common, appearing on 30-50% of newborns. They are small blood vessels (capillaries) that are visible through the skin. They are most common on the forehead, eyelids, upper lip, between the eyebrows, and the back of the neck. They may be more noticeable when the infant cries or during temperature changes. They often fade as the infant grows. Salmon patches on the back of the neck may not fade but are usually not noticeable as the hair grows.

• Skin markings that develop before or shortly after birth
• Skin rash or lesion that is red
• Skin markings that look like blood vessels

All birthmarks should be examined by a health care provider. Diagnosis is based primarily on the appearance of the skin lesion.

A biopsy, CT scan or MRI of the area may confirm deeper birthmarks, for instance, in the abdomen.