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Facial pigmentary disorders are a common reason why patients with skin of color seek dermatology care. Experts offer insights for establishing the diagnosis and choosing treatment.
Roopal V. Kundu, M.D.Facial pigmentary disorders in patients with skin of color (SOC) encompass a number of common and uncommon conditions, and so careful history and examination are important for making an accurate diagnosis that will guide safe and effective treatment, say Roopal V. Kundu, M.D., and Neelam A. Vashi M.D.
“It is important that clinicians get to know the patient and his or her practices and combine that information with the findings of a clinical examination that uses our eyes and appropriate diagnostic tools,” says Dr. Kundu, associate professor of dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL.
“When treating SOC patients, we must always be cognizant of the potential for causing hyper- or hypopigmentary changes using different treatment modalities. However, once the diagnosis is made, don’t be afraid to treat,” adds Dr. Vashi, assistant professor of dermatology, Boston University Medical Center, and director, Boston University Center for Ethnic Skin Cosmetic and Laser Center, Boston, Mass.
Melasma is one of the more common conditions seen in this population. The diagnosis, however, can sometimes be confused with other disorders. Their tips included using a Wood’s light to identify epidermal versus dermal melasma and to consider alternate diagnoses depending on location of pigmentation.
Regarding treatment, they note sun protection is essential in the management of melasma, and new sunscreens containing iron oxide pigments provide a better color match for patients with darker skin.
“In addition, these products block visible light as well as UV irradiation, which is important considering evidence that visible light also stimulates melanin production,” Dr. Kundu says.
She adds that patients with facial hyperpigmentation can also be counseled about camouflage tactics using sunless tanners or pigmented make-up, which should be chosen with a cosmetics consultant’s guidance for good skin color matching.
Hydroquinone is also a mainstay in treating melasma and other hyperpigmentary disorders. When using an extemporaneously compounded preparation, the pharmacist can be instructed to add 500 mg ascorbic acid, which will reduce hydroquinone degradation by oxidation. When using commercially available generic products, clinicians should consider transitioning between different vehicles rather than abandoning the treatment if the initial formulation is not sufficiently effective.
Chemical peels offer a useful adjunct to topical treatment for melasma, and using a layering technique combining a low concentration glycolic acid peel following by a trichloroacetic acid or salicylic acid peel can provide better results with minimal side effects. On the other hand, lasers should be used with great caution since they don’t produce a durable benefit and can cause hypopigmentation or postinflammatory hyperpigmentation.
Discussing postinflammatoryhyperpigmentation (PIH), Dr. Vashi points out that acne is its most common cause in patients with SOC, which speaks to the role of early and aggressive treatment of acne as a preventive measure.
“Dermatologists should have a lower threshold to prescribe systemic treatments for acne in persons with skin of color,” she says.
In patients using hydroquinone, exogenous ochronosis should be considered in patients who appear to have resistant disease. While this complication of hydroquinone has been uncommon in the United States, it can be readily diagnosed clinically using a dermatoscope that would reveal amorphous blue-gray macules or areas that obliterate follicular openings.
“Exogenous ochronosis can present a treatment challenge, but experience is emerging to suggest that the Q-switched 1064-nm Nd:YAG laser can be an option,” Dr. Kundu says.
Dermatologists should also keep in mind that melasma and hyperpigmentation may be misdiagnosed in patients who have vitiligo. These situations underscore the value of examination with a Wood’s light to differentiate between hyperpigmentation and depigmentation.
“Don’t be misled by a patient who comes in with a complaint about dark patches,” Dr. Vashi says.
Other conditions that can be confused with melasma include Hori naevi, which should be suspected in Asian patients, and dense lentigines and freckles localized to the malar cheeks.
“It is important to differentiate between melasma and lentigines since the Q-switched Nd:YAG laser, not hydroquinone, is the optimal treatment for lentigines,” said Dr. Kundu.
Pseudofolliculitis barbae is another relatively common hyperpigmentary disorder in SOC patients and is also fairly easy to diagnose, although the lesions are sometimes mistaken for acne vulgaris. To avoid that confusion, clinicians should look for localization of the lesions at the base of curved hair follicles and know that pseudofolliculitis barbae generally affects African-American and Hispanic patients.
The long pulse 1064-nm Nd:YAG laser is also a useful tool for treating pseudofolliculitis barbae, but the fluence should be set appropriately in order to avoid paradoxical hypertrichosis as a consequence of energy stimulated hair growth.
“Using pre- and post-treatment cooling to protect the adjacent skin will help prevent PIH when using higher fluences,” Dr. Vashi said
Dermatosis papulosa nigra is also a common hyperpigmentary problem in patients with African heritage. In contrast to pseudofolliculitis barbae, dermatosis papulose nigra is best treated with electrodesiccation, Dr. Kundu says.
“Electrodesiccation is both more efficacious and more economical than a laser,” she says.
She recommends using a low setting, doing a test spot first, and then either gently wiping away the top of the lesion or allowing it to fall off naturally to prevent PIH.
Dermatologists should also remember that acanthosis nigricans can occur on the face, and this diagnosis should be considered when there is hyperpigmentation of skin bilaterally in the hollows of the cheeks in patients who are obese or with diabetes.
“Remember this is a disorder of keratinization, and so the treatment is with keratolytics, not lightening agents that target the melanocytes,” said Dr. Vashi, adding there are reports of response using chemical peels.
Maturational dyschromia may be the diagnosis in very dark (skin phototypes V-VI) SOC patients with diffuse ill-defined hyperpigmentation on the lateral forehead and cheekbones. Considered a form of photodamage and aging, its management includes hydroquinone and sun protection.
Lichen planus pigmentosus is an uncommon variant of lichen planus that occurs mostly in skin phototypes III-V and involves sun exposed and flexural areas. Recent evidence shows many patients with concomitant disease of frontal fibrosing alopecia which is a scarring alopecia that also involves loss of lateral eyebrow hairs and perifollicular papules and pustules.
Idiopathic eruptive macular hyperpigmentation is a rare condition that might be considered in the differential diagnosis of what appears clinically to be PIH or a fixed drug eruption. Characterized by asymptomatic brown macules on the face, there are only 24 reports of idiopathic eruptive macular hyperpigmentation in the literature. Clinical cues to its diagnosis include absence of prior inflammation or drug exposure. According to the reports, this new entity seems to resolve gradually with time and does not recur.
“Cultural dermatoses” should also be kept in mind in the differential diagnosis of hyperpigmentation, recognizing that the SOC population comprises a variety of different ethnicities with various cultural practices. Culprits include bindi wear, mechanical skin trauma during praying, threading for removing unwanted hairs, and use of henna hair dyes, which are often adulterated with paraphenylenediamine.
Disclosures: Dr. Vashi is a consultant to L’Oreal USA. Dr. Kundu has no financial relationships with any commercial interests.