Skin pigmentation

Pigmented skin lesions are patches on the skin which can appear black, brown or blue. These patches are the result of activity involving melanin (the brown pigment of the skin) or blood.

These pigments can be either benign (medically harmless) in nature, or they can be malignant (skin cancer). For this reason, it is always advisable to have any pigmented lesions and conditions on your skin checked by your GP and/or a dermatologist.

Benign skin pigmented lesions and conditions include:

Treating benign pigmented lesions depends heavily on the type and cause of the pigmentation and the underlying skin type. Other skin conditions present can also affect the choice of treatment. Possible options include bleaching cream, skin peels, IPL, pigment lasers, ablative lasers, fraxel lasers.

Malignant skin pigmented lesions include:

  • basal cell carcinoma (BCC)
  • squamous cell carcinoma (SCC)
  • melanoma

Most pigmented skin lesions are not cancerous. However, if a pigmented lesion has changed in shape or colour, is bleeding or is persistently itchy, then we strongly suggest you consult your Dermatologist to have it assessed.

If you doctor believes the pigmented lesion to be of concern, a biopsy will be performed. This will most likely be in the form of a punch biopsy, which removes a small piece of the lesion, or a shave biopsy, which shaves off a section of the top of the lesion. Both of these procedures are quick but will require a local anaesthetic to be used to the area. If the doctor suspects the lesion to be an advanced cancer, other forms of testing may be conducted.

If the lesion is confirmed as a BCC or SCC, treatments can include a cream that removes the lesion such as surgery, curette and cautery, laser removal of the lesion or radiotherapy.

If the lesion is shown to be a melanoma, your dermatologist will advise the best treatment for you, given the stage of the cancer and the location of the lesion.

What causes pigmented skin lesions and am I at risk of developing them?

The colour of skin and hair is mainly determined by the amount of brown melanin pigment present in the skin, mixed with the blue of deoxygenated blood, red from oxygenated blood and yellow from carotenoids in the diet.

The constitutional colour of white, brown or black is determined by the amount of melanin in skin and how the skin phototype responds to UV exposure, either by burning or by tanning.

Brown pigmentation is an increase in the melanin of the pigmented area. This can occur because of an increase in pigment cells to the area or from an increased production of melanin.

There are many different reasons why non-malignant pigmented skin lesions occur.

Birthmarks are random patches of discolouration, apparent from birth. There is no known cause of these lesions.

Some brown pigmented lesions are the result of previous actions, such as scarring or inflammatory conditions. In these cases, the skin has proven sensitive to the “trauma” of these previous activities and skin colour is part of the skin’s response.

However, most commonly, sun exposure is the cause of skin pigmentation. UV light stimulates melanocytes (pigment cells in the skin) to manufacture the pigment called melanin. This is what is responsible for your tan and also the unwanted dark patches on your skin. Such sun-related pigmented patches my take 10-20 years to develop, which is why pigmentation is much worse in middle-aged and older skin. Triggers of pigmentation in younger women more often include pregnancy and the oral contraceptive, though excessive sun exposure can also induce discolouration.

People who tan easily and don’t burn, are more susceptible to skin darkening from a burn, wound, acne or skin irritation, than those with fairer skin. However, every skin type is susceptible to UV induced discolouration, which is why sunscreen needs to be used by people of all skin types.

In general, the fairer your complexion, the easier it is to treat pigmentation with IPL or lasers. The darker the skin, the greater the risk of burning, darkening or hypopigmentation (over-lightening of the skin) from light-based treatments. Asian skin is particularly tricky, even when it looks pale, as the underlying pigment can discolour. For this reason, Dr Poon has developed specific strategies for the management of Asian skin problems.