Hyperpigmentation

Hyperpigmentation results from any injury to the melanocytes which sit in the basal (base) layer of the outer layer of the skin (epidermis).

Melanocytes are designed to release melanosomes (which contain the pigment melanin) into their surrounding epidermal cells in response to UV exposure. Unfortunately, when melanocytes are injured by excessive sun exposure, hormones, inflammation or injury, they release their melanin in an abnormal way.

Examples include the vertical clumping of melanin which forms freckles in fair skins exposed to too much sun; horizontal clumping seen when melanocytes are oestrogen-sensitive or exposed to long-term high UV levels (melasma or chloasma); or the pigmented scarring seen in healed wounds in darker skins.

Hyperpigmentation is a complex and often unpredictable response of the melanocytes to a range of triggers. It is far more likely to occur in darker skin, but also in mixed-race skins.

Types of hyperpigmentation

Freckles

Can appear in fair skins from as young as 2 years old. They are caused by an uneven distribution of melanin in sun-exposed areas.

Chloasma / Melasma

Can appear in women from teens to old age. May be purely hormonal (pregnancy or the OC pill), hormonal combined with sun exposure (usually worsens during summer), or purely from excess sun exposure. Particularly common in mixed-race skins and Fitzpatrick type 3 and above.

Sun spots (Solar lentigines)

Generally seen in fair skins over the age of 35 in sun-exposed areas — hands, temples, chest. Sun spots and freckles can be difficult to distinguish; the key difference is that freckles can appear at any age, while sun spots tend to appear after 30.

Post-inflammatory hyperpigmentation (PIH)

Occurs after any injury to the skin. Particularly common in darker and mixed-race skins — it is almost guaranteed to occur if you already have a hyperpigmented scar.

Management of hyperpigmentation

Freckles

In skin types 1 and 2, freckles can be safely removed by laser or IPL. They generally respond very well — darkening after treatment and then flaking off the skin after 7–10 days. Freckles will recur if the client continues to get sun exposure.

Chloasma / Melasma

Laser and IPL can be tried for fair skins with melasma, however results may vary. Pure hormonal melasma tends to reverse once the hormone stimulus is removed. However, because of Australia's high UV environment, truly "pure" hormonal melasma is rare — most cases are mixed, making treatment responsiveness harder to predict.

If chloasma/melasma responds well to laser/IPL, it is essential to practise maximum sun protection and use a Lighten cream as a preventative. Chloasma/melasma has a very high recurrence rate.

Managing treatment-resistant melasma: