raised red patch on ds's scalp - any ideas

[sleepymama]

A couple of weeks ago I noticed a tiny red raised spot beggining to appear on my then 13week old ds. He's now 18 weeks tommorrow and the spot has grown in size and looks like a teardrop sized raised red bump. Its quite dry and has no pus. In the last couple of days ds is putting his hans to the side of his scalp and moving his hed from side to side as though it is itching him. I'm not sure what it could be. He doesn't appear to have this anywhere else but I'm a bit concerned about how the bump has grown rather than just dissappeared.
Anyone have any ideas?

DD had what looked like a bruise on her eyebrow when she was about 6 weeks. Have you been to the docters?

It grew into a group of blood vessels and kept growing untill she had steroid injections in it.

No Have not been as yet as sometimes its hardly noticable and during the day does not seem to bother ds at all. Its at night the it seems to itch him.