#AskID : Noticing a new mole with Prof Niki Ralph

We asked Prof Niki Ralph:
Moles, also known as naevi ,come in a variety of shapes and sizes. Congenital naevi, also commonly referred to as birthmarks, may develop before or shortly after birth. They are essentially coloured skin markings. Congenital naevi tend to be slightly larger than other benign naevi, which we acquire as we age, (“acquired naevi”).
Moles can be further classified depending on the part of the skin which they arise from. Epithelial naevi arise from the outermost layer of the skin and often appear brown in colour, whereas dermal naevi arise from the next layer of skin (deeper in the dermis) may be more skin coloured, sometimes with small blood vessels visible within them. They are particularly common on the face/neck and are a raised type of mole.

Naevi (moles) are caused by clusters of cells in the skin. They may be vascular naevi (arising from blood vessels), melanocytic naevi (clusters of melanocytes/pigmented cells), epidermal naevi due to clusters of keratinocytes and so on.
The exact cause as to why they occur is unknown but may be due to localised abnormalities of certain genes. There is also no way to prevent moles from forming.

It is normal for the following to happen with regard to moles:
• Babies may be born with moles or develop some shortly after birth
• For new moles to appear during childhood including teenage years
• For moles to darken during pregnancy
• For moles to fade/disappear as you get older

What is not normal is if a mole begins to change shape, size or colour. It is therefore important to have a new or existing mole checked by your doctor if the following occurs:
Asymmetry – the mole changes shape and becomes asymmetrical
Border – the edges of the mole become irregular/jagged edges, not the typical smooth oval/round shape
Colour – the mole changes colour and may have 2 or 3 colours within it such as black or pink areas within the original brown mole
Diameter – The mole increases in size > 6mm
Evolution – We all have moles, however if a new mole appears and continues to change or an existing mole changes with regard to alteration of shape, size or colour, this may indicate there is something wrong and you should have the mole checked with your doctor.
Moles can of course become traumatised, especially moles which are raised up from the skin. They may be scratched/rubbed, catch on clothing etc. This does not always mean there is something wrong, however if a mole bleeds or has a crust/scab form on it and you don’t recall any trauma to the area then you should seek advice with your doctor.
Not all lesions on the back of the hands are moles. This is a chronically sun-exposed site therefore as we age we may develop sun -nduced brown spots on the back of the hands called a solar lentigo (sun freckle). They tend to be flat, brown marks on the back of the hands, especially appearing after the age of 40. They may appear darker just after the Summer months due to constant UV exposure and may fade to lighter brown colour during Winter months. If however, you notice that this type of lesion changes in shape, size, colour and continues to evolve then it should be examined by your GP.
Of course, if you are already attending your dermatologist on a regular basis due to a personal or family history of previous atypical moles or skin cancer then you may contact your dermatologist directly for any new or changing lesions to be examined.
It is recommended that you attend for a full skin examination with your dermatologist on a regular basis if you have had previous skin cancer such as non-melanoma or melanoma skin cancer. These regular check-ups should occur every 3–12 months depending on the type of skin cancer you had.
If you have numerous moles, you should use SPF daily on all sun exposed sites especially face, neck and back of the hands even during Winter months, as UVA penetrates glass, therefore can come through car windows for example.
You should perform self-surveillance of your moles on a regular basis to monitor for changes and you may also take photographs of moles in difficult to see locations such as the back/back of the legs.
Follow the ABCDE guidelines of how to monitor for changes in moles and if you have any concerns about a new or changing lesion, you should book an appointment with your GP or dermatologist