Q: I am a 21-year-old man. I have a birthmark, about the size of an egg, on my left shoulder. In the past year or so, I have noticed moles and even hair growing on it.

Should I see a doctor about it? Can the birthmark or the moles on it be removed?

A: There are different birthmarks. Some examples are: port wine stains, which are coloured red; cafe au lait macules, which, as their name suggests, are coffee coloured; and congenital naevi, which are large, dark-coloured moles.

Without a more detailed description of the type of birthmark you have, it would be difficult for me to give an accurate and complete answer to your questions.

However, as a general rule, if raised moles start to appear within a birthmark which was previously flat and not raised, you should consult a dermatologist for an assessment. Occasionally, the moles may need to be biopsied or sampled and sent for microscopic analysis if they look suspicious.

Some birthmarks can be treated with lasers or surgery.

Dr Chris Foo is a dermatologist at Raffles Hospital.

This article was first published in Mind Your Body, The Straits Times.