logo

DermNet NZ

  

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Melasma

What is melasma?

Melasma, sometimes called chloasma (which means green skin), appears as a symmetrical blotchy, brownish pigmentation on the face. The pigmentation is due to overproduction of melanin by the pigment cells, melanocytes. It can lead to considerable embarrassment and distress.

Chloasma Chloasma Chloasma
Melasma / chloasma

More images of melasma ...

What causes melasma?

The cause of melasma is complex. There is a genetic predisposition to melasma, with at least one-third of patients reporting other family members to be affected. In most people melasma is a chronic disorder.

There are several known triggers for melasma.

More commonly, it arises in apparently healthy, normal, non-pregnant adults and persists for decades. Exposure to ultraviolet radiation (UVR) deepens the pigmentation because it activates the melanocytes.

Research is on-going to pinpoint the roles of stem cell, neural, vascular and local hormonal factors in promoting melanocyte activation.

What are the clinical features of melasma?

Melasma is more common in women than in men; only 1-in-4 to 1-in-20 affected individuals are male (depending on the population studied). It generally starts between the age of 20 and 40, but can begin in childhood or not until middle-age. Melasma is more common in people that tan well or have naturally brown skin (Fitzpatrick skin types 3 and 4) compared with those who have fair skin (skin types 1 and 2) or black skin (skin types 5 or 6).

Melasma presents as macules (freckle-like spots) and larger flat brown patches. There are several distinct patterns.

Melasma is sometimes separated into epidermal (skin surface), dermal (deeper) and mixed types. A Wood lamp may be used to identify the depth of the pigment.

Type of melasma Clinical features
Epidermal
  • Well-defined border
  • Dark brown colour
  • Appears more obvious under black light
  • Responds well to treatment
Dermal
  • The most common type
  • Ill-defined border
  • Light brown or bluish in colour
  • Unchanged under black light
  • Responds poorly to treatment
Mixed
  • Combination of bluish, light and dark brown patches
  • Mixed pattern seen under black light
  • Partial improvement with treatment

How is the diagnosis of melasma made?

The characteristic appearance of melasma means diagnosis is usually straightforward and made clinically. Other disorders that may be considered include:

Occasionally, skin biopsy may be performed to confirm the diagnosis. Histology varies with the type of melasma. But some degree of each of the following features is usually found.

The extent and severity of melasma can be described using the Melasma Area and Severity Index (MASI).

What is the treatment of melasma?

Melasma can be very slow to respond to treatment, so patience is necessary. Start gently, especially if you have sensitive skin. Harsh treatments may result in an irritant contact dermatitis, and this can result in postinflammatory pigmentation.

Generally a combination of the following measures is helpful.

General measures

Topical therapy

Tyrosinase inhibitors are the mainstay of treatment. The aim is to prevent new pigment formation by inhibiting formation of melanin by the melanocytes.

Other active compounds in use include:

Superficial or epidermal pigment can be peeled off. Peeling can also allow tyrosinase inhibitors to penetrate more effectively. Agents to achieve this include:

Currently, the most successful formulation has been a combination of hydroquinone, tretinoin, and moderate potency topical steroid, which has been found to result in improvement or clearance in up to 60-80% of those treated. Many other combinations of topical agents are in common use, as they are more effective than any one alone. However, these products are often expensive.

Oral treatment of melasma

Oral medications for melasma are under investigation, including tranexamic acid (a prescription medicine in New Zealand). None can be recommended at this time.

Devices used to treat melasma

Machines can be used to remove epidermal pigmentation but with caution – over-treatment may cause postinflammatory pigmentation. Fractional lasers are preferred and have been approved by the FDA for treating melasma. Patients should be pretreated with a tyrosinase inhibitor (see above).

The ideal treatment for a quick result is just to destroy the pigment, while leaving the cells alone. Intense pulsed light (IPL) appears to be the most effective light therapy investigated so far. The topicals described above should also be used before and after treatment. Pigmentation may recur. Several treatments may be necessary and postinflammatory hyperpigmentation may complicate recovery.

Conventional carbon dioxide or erbium:YAG resurfacing lasers and pigment lasers (Q-switched ruby and Alexandrite devices) are sometimes used, but they have a high risk of making melasma worse. Dermabrasion and microdermabrasion are not recommended, as they may also cause postinflammatory hyperpigmentation.

What is the outcome of treatment of melasma?

Results take time and the above measures are rarely completely successful. About 30% of patients can achieve complete clearance with a prescription agent that contains a combination of hydroquinone, tretinoin and a topical corticosteroid.

Unfortunately, even in those that get a good result from treatment, pigmentation may reappear on exposure to summer sun and/or because of hormonal factors. New topical and oral agents are being studied and offer hope for effective treatments in the future.

Related information

References:

 

DermNetNZ:

Other websites:

Books:

See the DermNet NZ bookstore

Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand.

DermNet NZ does not provide an online consultation service.
If you have any concerns with your skin or its treatment, see a dermatologist for advice.