Quick Diagnosis
Jennifer M. Tran, BHSc (1T3), Faculty of Medicine, University of Toronto
An-Wen Chan, MD, DPhil, FRCPC, Division of Dermatology, Women’s College
Hospital, University of Toronto
Report of a Case
A 49 year-old healthy woman Malaysian woman presented with asymptomatic
brown macules and patches on both cheeks, nose bridge, and forehead. She first
noticed this change in her skin nearly 20 years ago, a few months after her
second pregnancy. She has not noticed any change or improvement over the
past 20 years, despite several trials of cosmetic lightening creams.
Figure 1. Representative photo of melasma.
What is the diagnosis?
And the diagnosis is...
Diagnosis: Melasma
Hyperpigmentation is extremely common in pregnancy and occurs most often
around the areola, abdomen (linea nigra), axilla, face, and medial thighs.1 One of
the most common examples of pregnancy-associated hyperpigmentation is
melasma (from the Greek word melas, meaning “black), also known as the “mask
of pregnancy” or “chloasma” (from the Greek word chloazein, meaning “green”).2
Melasma is an acquired, symmetrical hyperpigmentation of sun-exposed areas of
the body, most commonly occurring on the face. It is estimated that 5-6 million
women in the United States alone are affected by the condition. Melasma affects
mostly women (who account for over 90% of all cases), with Fitzpatrick skin
types III, IV, V, or VI. Correspondingly, melasma is seen more commonly in
people of Asian, Hispanic, and African-American descent.4 Melasma, though
benign, can be extremely psychologically distressing and has been shown to
have a significant impact on quality of life, social, and emotional wellbeing. 5
Etiology
The exact cause and pathophysiology of melasma remains unknown, though
certain risk factors have been identified. Pregnancy is a clear precipitant, as well
as hormone replacement therapy and oral contraceptives.2 Although cessation of
exogenous hormone use can cause remission of the condition, pregnancyassociated melasma can last for decades after pregnancy. Biopsies of melasmaaffected skin have shown increased estrogen receptors, further suggesting a role
for hormonal influence in the development of the condition.6,7 Several studies
have also suggested a genetic component, with an estimated 33% - 56% of
patients reporting a positive family history.8,9,10 Sun exposure also plays a key
role in both the development and prevention of the condition.2,10
Clinical Features
Melasma tends to present as hyperpigmented macules and patches that range
from light to dark brown, with occasional grey-tinge. Pigmentation may be guttate
or confluent. Darker patches of skin gradually develop over weeks to months on
sun-exposed areas of the face, particularly on the cheeks, forehead, and nose.2
Pathology
Melasma can be divided into three main patterns based on the histopathological
location of increased melanin: epidermal, dermal, and mixed (a combination of
epidermal and dermal). Histological analysis of melasma biopsies have shown
increased solar elastosis, melanocytes, melanophages, and melanin deposition.
Melanocytes also seem to be more biologically active, exhibiting increased
numbers of dendritic processes and organelles related to synthesis (Golgi
apparatuses, rough endoplasmic reticulum, and mitochondria).2,11-14
Diagnosis
Melasma is diagnosed based on primarily on clinical history and examination.
Wood’s lamp examination (UV light) may in some cases provide further detail
about the histological subtype of melasma (epidermal, dermal, or mixed).
Dermatoscopic examination can reveal an annular-granular pattern in melasma
lesions, but does not often provide significant diagnostic utility in clinical practice
given the characteristic history and physical exam findings that accompany most
cases of melasma.15 Some mimickers of melasma include solar lentigines,
acanthosis nigricans, post-inflammatory hyperpigmentation, minocycline-induced
hyperpigmentation, and frictional melanosis.2 With conscientious and thorough
examination as described above, and a skin biopsy if necessary, melasma can
usually be distinguished from these other dermatological problems.2
Treatment
Melasma remains a common yet extremely difficult to treat condition. Sun
protection is a key component of any treatment plan. In general, conventional
treatments include sun protection, bleaching creams (e.g. hydroquinone), acne
treatments (e.g. topical retinoids), and facial peels (e.g. glycolic acid peels).
Triple-combination creams including hydroquinone, tretinoin, and steroids have
also been used. A recent Cochrane review4 of 20 studies (n=2125 participants in
total) reviewed 23 different topical and systemic treatments for melasma, and
found the greatest improvement with triple-combination creams compared to
hydroquinone alone (RR 1.58, 95% CI 1.26-1.97) or with dual combination
creams of hydroquinone and tretinoin (RR 2.75, 95% CI 1.59 to 4.74),
hydroquinone and fluocinolone acetonide (RR 10.50, 95% CI 3.85 to 28.60), and
tretinoin and fluocinolone acetonide (RR 14.00, 95% CI 4.43 to 44.25). The
adverse events most commonly reported were mild and temporary, including skin
irritation, burning, and itching. Other treatment modalities that have been recently
investigated include laser treatments such as Q-switched ruby laser,
erbium:yttrium aluminum-garnet laser, carbon dioxide laser, intense pulsed light,
and fractional resurfacing. These modalities have generally shown only modest
and transient effect4,16 and often pose a significant risk of worsening the condition
with post-inflammatory hyperpigmentation. More trails need to be conducted in
order to further characterize the efficacy of such treatment modalities.
Back to the case
This patient was diagnosed with melasma (epidermal subtype) and reassured of
the benign nature of her condition. We discussed the importance of ongoing sun
protection, including wearing a sunscreen of at least SPF 30 and clothing
barriers. As per the patient’s request, we also discussed cosmetic treatments
including topical hydroquinone, triple-combination creams, and glycolic acid facial
peels. The patient opted for a trial of hydroquinone cream and was scheduled to
return in 8 weeks for follow-up.
Conclusions
- Melasma is a common and benign skin disorder characterized by
symmetrical macules and patches of hyperpigmentation on the face
-
-
It is associated with cosmetic disfigurement and significant psychological
distress
Though the pathophysiology of melasma is not yet fully understood, risk
factors include pregnancy, exogenous hormone use, family history, darker
skin type, and sun exposure
Current treatments are variable in their efficacy and include sun
protection, topical treatments, chemical peels, and laser treatment
More research needs to be done to further elucidate the pathophysiology
and potential treatments for this chronic and difficult to treat condition.
References
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Acad Dermatol 2011;65(4):689-97.
3. American Academy of Dermatology. Dermatologists Dis-’Patch’ Dark Side of
Melasma.Available at: http://www.prnewswire.com/newsreleases/dermatologists-dis-patch-dark-side-of-melasma-58900367.html
(Accessed March 18, 2012).
4. Rajaratnam R, Halpern J, Salim A, Emmett C. Interventions for melasma.
Cochrane Database of Systematic Reviews 2010, Issue 7. Art. No.: CD003583.
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