Melasma is a common problem in darker skin types (Fitzpatrick phototypes IV-VI) such as Asian and African skins. It is a chronic and rather difficult to treat skin disorder. Women are more commonly affected than men. Melasma occurs when pigment producing cells (melanocytes) produce too much pigment called melanin. Although the exact cause of melasma is not fully established, it has clear association with increased exposure to sun light (especially ultraviolet rays) and female hormonal activity. This is the reason why there is increased incidence of melasma during pregnancy and in those women taking oestrogen containing drugs like oral contraceptive pills and hormone replacement therapy. In one third of patients there is genetic predisposition.
Melasma can present as large brown or brown-gray/blue patches or small freckle like spots on different parts of face such as cheeks, nose, forehead and chin. Depending on which parts of the face are affected, melasma can be: centro-facial (cheeks, upper lip, forehead, chin and nose), malar (cheeks and nose) or mandibular (jawline). Melasma can be superficial (epidermal), deep (dermal) or mixed types.
Melasma and other types of pigmentation can be treated using similar treatment methods. Many of the topical treatments used in the treatment of melasma basically act by inhibiting tyrosinase which is an enzyme produced by malanocytes and is crucial component in the production of melanin pigment in the skin. When the activity of tyrosinase is restricted, the skin makes less melanin. Examples of tyrosinase inhibitors include hydroquinone, kojic acid and arbutin. Other topical agents used in the tretment include anti-oxidants and retinoids.
One important aspect of treatment of melasma to keep in mind is that the results take time to be noticeable and are rarely 100% successful. Even in those lucky patients who get initial good results, pigmentation can re-appear after some time of treatment especially if patients are not particular with strict sun protection or under the influence of female hormones as if a woman gets pregnant.
General measures:
-Complete sun protection throughout the year with the use of broad-spectrum sun block creams is an integral part of treatment of melasma.
-discontinue hormones containing contraceptive pills
– use a gentle skin cleanser and mild moisturiser on a regular basis
-In order to disguise the pigmented areas, cosmetic camouflage can be used
Hyroquinone: This is the most commonly used topical drug for the treatment of melasma and other pigmentation disorders. Although the misuse of hydoquinone can cause adverse effects on the skin such as worsening of pigmentation (ochronosis), when used with caution under the supervision of an expert skin practitioner, it is a safe and effective medication. Typically it is available in topical preparation containing 2-4% hydroquinone applied to affected skin once a day for maximum 3-4 months. Improved results can be achieved when it is used in combination with other ingredients such as retinoids, kojic acid, glycolic acid and anti-oxidants. One of the most popular combinations is hydroquinone, week topical corticosteroid and tretinoin. The main adverse effects are skin redness and stinging
L-ascorbic acid or Vitamin-C: This is an anti-oxidant that has depigmenting effect. It also has anti-inflammatory and photo-protective properties and reduces the oxidative stress.
Glycolic acid: it is used to reduce pigmentation due to its exfoliant or skin peeling effects including surface pigmentation patches and dark marks.
Kojic acid: it is mostly included in formulations, it can sometimes cause irritant contact dermatitis
Retinoids or Vitamin A: include low-strength retinoid called retinol that is available commercially over the counter and higher strength retinoid tretinoin which is a prescription drug and available is various strengths. Retinoids work by increasing cell turn over that reduces the time for melanocytes to transfer pigment/melanin to surrounding skin cells called keratinocytes. Its most common side effect is skin irritation and redness. Retinoids must not be used in pregnancy due to risk of birth defects in the foetus
Cysteamine: it is a relatively new treatment available as cream. Its mechanism of action is unclear but seems to act through inhibition of tyrosinase mentioned above.
Chemical peels: These can be effective second line treatment for melasma and hyperpigmentation if carried out carefully by experienced practitioners who deal with pigmented skin types on regular basis. The main risk is prolonged hyperpigmentation in darker skin types unless used with caution. Chemical peels containing a combination of salicylic acid and mandelic acid are safer and more effective than glycolic acid peels.
Tranexamic acid: It has been used as cream and also injected into the skin with some benefit. It may also cause allergy or irritation. Oral tranexamic acid in low doses has been shown to be effective and safe option in the treatment of melasma. The main risk is thrombo-embolism.
Glutathione: this is an anti-oxidant that has been used in oral, topical and injection form to lighten the skin. It has the potential to cause serious adverse effect in systemic form so has to be administered very cautiously and needs close monitoring with regular blood tests under the supervision of experienced clinicians.
Lasers and IPL: Different laser machines have been used to destroy the pigment in the skin with Q-switched Nd-YAG laser being the most commonly used one. Others include fractional lasers and intense pulsed light with variable results but several treatment sessions are required. The main risk is post-inflammatory hyper-pigmentation.
In summary, melasma is a common, chronic and disfiguring skin problem that affects many Asian women (and some men). Its treatment is not satisfactory but with proper skin care using broad spectrum sun block creams, removing the triggering factors and perseverance with treatment under the care of experienced clinicians, improvement in pigmentation can be achieved.