Clinical nuances of psoriasis in darker skin

There are important differences in and misconceptions about the prevalence, clinical presentation and treatment of skin of color versus Caucasian psoriasis patients.

Andrew F. Alexis, M.D., M.P.H., chairman of dermatology at Mount Sinai St. Luke's and Mount Sinai West and director of the Skin of Color Center at Mount Sinai Health System, New York, N.Y., presented on the topic of psoriasis in skin of color at The Skin of Color Seminar Series, held April 30 and May 1 in New York City.

For starters, psoriasis is not as rare in skin of color as once thought.

“Older epidemiologic studies suggested that the prevalence was very low among African Americans and others of African ancestry,” Dr. Alexis says. “That has since been refuted with more recent studies that have shown the prevalence to be much higher than what was previously reported. That being said the prevalence of psoriasis among African Americans is still less than that of Caucasians.”

In a study published March 2014 in Journal of the American Academy of Dermatology (JAAD), researchers found that psoriasis prevalence was 3.6 percent among Caucasian U.S. adults, versus 1.9 percent among U.S. African Americans and 1.6 percent among Hispanics.

Clinical presentation differences

It can be challenging for dermatologists to diagnosis psoriasis in skin of color because darker skin patients’ background melanin pigmentation can mask visible erythema, which is typically associated with psoriasis.

“So, instead of looking salmon pink or clearly erythematous, psoriasis plaques in darkly pigmented skin can have a violaceous hue or can be grayish in terms of the appearance,” Dr. Alexis says.

Another challenge to the diagnosis is that, in darker pigmented skin, it can be difficult to distinguish psoriasis from other scaly inflammatory disorders, such as lichen planus, discoid lupus or sarcoidosis. Dermatologists making the diagnosis in skin of color patients are more likely to need a biopsy to distinguish psoriasis from the mimickers, according to Dr. Alexis.

Treatment nuances

There is a high frequency of pigment alterations associated with darker skin types with psoriasis, according to the dermatologist.

“So not only do we need to be concerned about the scaling, redness and elevation of the psoriatic plaques, but also the sequelae of either hypo- or hyperpigmentation once the plaques are resolved,” Dr. Alexis says. “And that pigment alteration can last for many months after resolution of the psoriasis; so patients need to be counseled about this and given realistic timelines for clearance of the psoriasis, itself, as well as the pigmentary sequelae.”

Hyperpigmentation that results from psoriasis can be managed with bleaching agents once the psoriasis is cleared, Dr. Alexis says.

Another important treatment nuance in darker skin psoriasis patients is how dermatologists treat psoriasis that affects the scalps of African American women. The issue is that African American women tend to have different hair care practices and hair texture than Caucasians.

“When it comes to topical therapies, we have to prescribe a regimen that is compatible with that patient’s hair washing frequency, which tends to be less in African American women than in Caucasians. It also has to be compatible with hair styling practices,” Dr. Alexis says. “So, one has to take the extra step of involving the patient in the treatment decisions of vehicle selection and frequency of application when treating African American female patients with scalp psoriasis.”

Psoriasis treatments, including biologic therapies, have been less studied in skin of color versus Caucasian psoriasis patients, according to Dr. Alexis.

“When one looks at the demographics of trials for most of the biologics that are currently approved, the patients studied are about 90 percent Caucasian. That leaves us with limited data on treating patients of skin of color with biologic therapy,” he says.

That being said, Dr. Alexis was among the authors of a study in the Journal of Drugs in Dermatology, in August 2011, comparing the safety and efficacy of etanercept in different racial and ethnic groups with psoriasis. The researchers found no difference in safety and efficacy among the African Americans, Latinos, Asians and Caucasians, but they did observe differences in quality of life impact, with psoriasis having a greater quality of life impact in non-white patients than in Caucasians.

In another study involving adult outpatients at four academic medical centers published October 2015 in Clinical Rheumatology confirmed the quality of life finding and revealed more about the differences between African American and Caucasian psoriasis patients. Researchers of that study reported 30 percent of African American psoriasis patients had psoriatic arthritis versus 64.5 percent of Caucasian psoriasis patients studied. African Americans, however, had more severe skin involvement, with greater psychological impact and impaired quality of life.

The bottom line, according to Dr. Alexis, is dermatologists should be aware that psoriasis, clinically, can have different morphology in darker skin patients and is more likely to result in pigmentary changes than in lighter skin patients. Dermatologists should consider the clinical mimickers of psoriasis, and take into account cultural considerations, such as hair care practices in African Americans, as well as cultural perceptions of psoriasis in different ethnic groups, being sensitive to those differences, he says.

Patient counseling and treatments tailored to address these differences can improve patient outcomes and experiences, according to Dr. Alexis.

Disclosure: Dr. Alexis is an investigator for Dermira and Novartis, and is a consultant for Amgen and Novartis.