Pigment Problems: Understanding Skin Pigment
Skin contains cells that produce melanin pigment. Melanin gives us all the shades of skin colour from pale tan to dark black. These melanin cells can be over active, under active or in the wrong place. Some rare diseases, such as Addison’s Disease, can cause a suntan without exposure to the sun.
More common problems, such as fungal infections, can cause patches of paler or darker skin. Moles that are changing in character need a specialist opinion, so an accurate diagnosis for pigment problems is important, and occasionally a biopsy may be recommended. This is why, when you come to us with pigment problems, we will always arrange an appointment with a consultant dermatologist first. Even then it’s not possible to cure all brown marks.
We recommend that you let your GP know you are planning to see us as they may want to write a referral letter. In any case, we will want to write back with our findings. It is important that your GP is able to keep an overview of your health. If your concerns are purely cosmetic, you may refer yourself.
These are some causes of dark marks on the skin, with the more common first:
Solar Lentigoes or age spots, are flat brown marks that appear on sun exposed areas such as the backs of hands and the face.
Also known as liver spots they are harmless and have nothing to do with how well your liver functions. They are the result of years of sun exposure and are caused by a local increase in pigment producing cells. The dermatologist may recommend freezing or lasering them.
This a fairly common disorder that causes dark, blotchy patches on the face. The patches darken as they are exposed to the sun and will often turn brown in the summer and fade in winter. Although men are known to suffer from melasma, the condition usually affects women. It is commoner in women taking birth control pills or hormone replacement therapy.
When it appears in pregnant women, it is called the mask of pregnancy, or chloasma. This type of melasma usually disappears after a baby is born but not always. Women who have chloasma should wait several months after delivery before contemplating a cosmetic procedure. Women taking birth control pills who experience melasma should consider another form of contraception, including progesterone only pills. Changing pills, however, will usually have no effect on the melasma you already have. The dermatologist may suggest prescription bleaching creams, or a peel.
This results from any inflammatory injury to the skin. Acne can leave these sorts of marks, so can insect bites, oven burns, scars and eczema. Chemical peels or laser treatments can also cause hyperpigmentation in susceptible individuals. Even seemingly innocuous things like leg waxing and electrolysis can leave hyperpigmentation marks. The degree of hyperpigmentation varies depending on which part of the body it appears.
Discoloration on the torso and lower body tends to be much darker than discoloration appearing on the face. The darker your skin, the more prone you are to this type of hyperpigmentation. The dermatologist may recommend prescription fading creams, perhaps followed by a peel.
Moles are usually best left alone or cut out. This will always leave a scar. If you and your GP are concerned about a mole that is changing in character then an NHS referral is an appropriate option.
Seborrhoeic keratoses or warts
These are like age spots but have a rough surface. They occur on the body more than the limbs and are common in older people. They can be frozen off with liquid nitrogen. Sometimes a pale patch remains after the treatment.
Cafe au Lait Macules
These are large flat, evenly coloured brown marks. About 50% can be improved with laser treatment, but they have a tendency to return.
There are several sorts of pigmented birthmarks. Most are difficult to treat, but some can be improved with laser treatment. NHS referral is an appropriate option.