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. There is no known way to prevent birthmarks.
Diagnosis is based primarily on the appearance of the skin lesion .
Nevus flammeus type of hemangiomas may require no treatment unless they are disfiguring or psychologically distressing, or unless they develop new symptoms such as pain or change in appearance. Oral or injected cortisone may be used to reduce the size of a hemangioma that is growing rapidly and obstructing vision or vital structures. They are usually not treated unless symptomatic , or until a child is at least school age. However, port wine stains on the face should be treated at a young age with a yellow pulsed dye laser for best results and to prevent the often profound psychosocial problems caused by the port wine stain . Birthmarks rarely cause problems other than cosmetic changes.