Melasma: A Poorly Understood & Relapsing Disorder

Much like general hyperpigmentation, melasma represents an acquired form that most commonly affects an estimated five million women and often referred to as “the mask of pregnancy” due to hormonal changes.  The condition consists of brown or grayish-brown blotches─ typically on the forehead, chin, cheeks, upper lip or nose─ that can develop in women of all ages, can stay for decades, and is very difficult to treat.  Melasma is more likely to occur in darker skin types from Latin-America, Asia, Middle East, and Northern African.  These ethnic groups tend to have more active pigment-producing cells (melanocytes) that release too much pigment in certain areas of skin.  The mechanism is similar to what causes brown age spots and freckles, but the patches tend to be larger.

The processes and causes of melasma are complex. The pigmentation is due to overproduction of melanin granules (melanosomes) which are taken up by skin keratinocyte cells (epidermal melanosis) and deposited in the dermis by scavenger macrophage cells (dermal melanosis).  The epidermal form is characterized by brown color and is easier to treat with topical therapy, whereas the dermal or mixed type of melasma is more resistant to treatment due to pigment depth.   

Melanocytes in the epidermis of the skin are stimulated by a variety of factors, including genetic predisposition, normal (pregnancy) and exogeneous hormones (birth control pills, hormonal replacement drugs), thyroid disease, skin irritation (skin care products and treatments), stress, as well as sun exposure.  Aside from the clear role that melanocytes and their intracellular micro-pigment granules (melanosomes) play in the pathogenesis of melasma, there is increasing evidence that melasma also has a significant vascular relationship which is currently under investigation.  The exact molecular mechanisms of action are unknown but may be related to the actions of released growth factors and cytokines by melanocytes and other surrounding cells (keratinocytes, fibroblasts, macrophage scavengers, endothelial vascular cells) to stimulate the overproduction and release of melanosomes.

General Measures for Treatment  

• discontinue hormonal treatments if possible
• year-round life-long sun protection (wide brim hats, umbrellas)
• broad-spectrum (SPF 50+) with physical blockers (zinc or titanium)
• mild cleansers and light moisturizers
• cosmetic camouflage make-up to disguise pigmentation

Topical Therapy (consult with your dermatologist or plastic surgeon)

• tyrosinase inhibitors of melanin production (2-4% hydroquinone cream or lotion; kojik acid)
• azaleic acid (blocks tyrosinase enzyme) 
• ascorbic acid (vitamin C) inhibitor of pigment production through copper
• methimazole (anti-thyroid drug) cream reduces melanin synthesis 
• investigational agents (zinc sulfate mequinol, arbutin, deoxyarbutin from berries, liquorice) 
• extract, rucinol, and others topical corticosteroids (short-term)
• soy bean extract (thought to reduce transfer of pigment granules from melanocyte to skin cells)
• tranexamic acid cream under investigation─ may cause allergy or irritation
• tranexamic oral medication under investigation (lysine analogue that decreases melanogenesis)

Superficial Peeling Therapies

• topical alpha hydroxyacid peels (glycolic acid, lactic acid)
• topical retinoids (prescriptive retin-A , retinol, retinyl)
• salicylic acid peels

Device Therapies

• Picosecond Lasers (PicoSure) 
• fractional ablative and non-ablative lasers
• microneedling and combined topical creams
• intense pulse light (IPL)
• LED light

Summary

The pathogenesis and treatment protocols of melasma are complex and not yet fully understood.  Despite the wide array of high-technology energy and light-based devices available today, the fold standard for first-line treatment remains topical therapy using strict photo-protection with broad-spectrum sunscreens and either hydroquinone 4% cream, tretinoin, or triple-combination cream (TCC).  If you are not responding to topical treatments and avoidance therapy, the addition of device therapies can be recommended.  Not all melasma need be treated as some of them will fade away with time

Above all, you should seek close supervision under a licensed medical provider that can safely and effectively guide you to a more successful outcome with minimal complications for this vexing disorder.  The Sasaki Advanced Aesthetic Medical Center, under the supervision of Dr. Gordon Sasaki, specializes in the medical skin care treatment of melasma and generalized hyperpigmentations in its established InnoVesscence SkinCare Center and Device/injection Center.