Julie Fallon, of Ardgowan School, asks :-
Emma Wagstoff, of Rongotea School, asked:- Megan Sharrock, of Westland High School, asked:- Bryn Barlow, of King's High School, asked:-
What are freckles? What are freckles and why do only some people have them? Why do people get freckles when they're sunburnt?
David Young, a Dunedin skin specialist (a dermatologist), responded.
There are two main types of cell in the outer layer of the skin. The main type (which specialists call keratinocyte for short) forms the skin while the other type of cell (called melanocyte) supply pigment (dark colour) to the skin. When you tan the melanocyte cells produce more of the pigment (called melanin) and transfer it to the keratinocyte cells, resulting in a darker colour of the skin.
Freckles are where the skin has a localised increase in the production of melanin so that a small brown area appears.
Whether you develop freckles or not really depends on how fair your skin is. Therefore very fair skinned people such as red heads and some blondes are very likely to develop freckles whereas those with an olive skin or a darker skin (e.g. Polynesian or Asian) do not develop them.
Freckles are quite different to moles. Moles consist of a large local increase in the number of melanocytes. Freckles however consist of no increase in melanocytes but an increase in the production of melanin pigment from the melanocytes that are there.