When it comes to treating psoriasis in non-white patients, there is a paucity of data on differences in epidemiology, clinical presentation and approaches to treatment.
Dr. AlexisWhen it comes to treating psoriasis in non-white patients, there is a paucity of data on differences in epidemiology, clinical presentation and approaches to treatment.
“Although psoriasis appears to have a lower prevalence in non-white racial ethnic groups, including African Americans, it is by no means an uncommon or rare disease,” says Andrew Alexis, M.D., chair of the department of dermatology and director of the Skin of Color Center at Mount Sinai St. Luke’s and Mount Sinai West in New York City. He spoke on psoriasis at the Skin of Color Seminar Series (SOCSS) in New York City in May.
In fact, a recent study found a 1.9% prevalence rate of psoriasis in African Americans.
“This is much more common than previously reported,” Dr. Alexis tells Dermatology Times.
The clinical presentation of psoriasis in darker skinned individuals can vary, based primarily on the visual appearance. For example, because of the background melanin pigmentation, “the erythema may look more violaceous, hyperpigmented or dark brown or gray,” Dr. Alexis says. “Therefore, one has to train the eye to detect psoriasis-related erythema in darker skin types.”
Clues of psoriasis include the quality of the scale, the anatomic distribution and associated features.
There are scenarios, though, where a biopsy is needed to confirm the diagnosis of psoriasis.
“I find this is more frequent in darker skin types,” Dr. Alexis says.
For instance, patients with skin type VI may present with violaceous, gray, or hyperchromic scaly plaques without appreciable erythema.
“In these patients, it may be difficult to distinguish the psoriasis from lichen planus, cutaneous T-cell lymphoma or sarcoidosis in some cases,” Dr. Alexis says.
For treatment, a few studies have looked at potential racial ethnic differences in safety and efficacy.
“Once such study1 found comparable safety measures and efficacy outcome measures for the injectable TNF antagonist, etanercept (Enbrel, Amgen)” Dr. Alexis says.
However, in the above study from the Journal of Drugs in Dermatology in 2011, racial/ethnic differences in quality-of-life impact were observed. As measured by the Dermatology Quality of Life Index (DLQI), “baseline quality of life was actually worse in African American and Hispanic/Latino patients compared to Caucasians,” Dr. Alexis says.
More recently, Dr. Alexis was co-author of a poster at this year’s SOCSS that evaluated the safety and efficacy of the recently approved biologic agent brodalumab (Siliq, Valeant), for which there was no significant racial or ethnic differences in safety or efficacy.2
“Studies like this are important to understand whether there are any potential differences in safety and efficacy, particularly with biologics that are so specific in their target,” Dr. Alexis says. “Fortunately, we have not seen any significant differences with the studies that have been conducted thus far.”
An example of nuanced treatment is when psoriasis affects the scalp of women of African ancestry.
“One has to take into account the differences in haircare practices in this cohort and differences in hair structure that can affect the optimal topical therapies,” Dr. Alexis says.
Therefore, before prescribing, the patient’s hair-washing frequency needs to be determined, as well as what is involved in her hairstyle and preferred vehicle or formulation, whether it is a water-based solution, a lotion, an oil-based product or a foam.
“You need to have some discussion about these issues to integrate the treatment recommendation into their existing or preferred haircare practices,” Dr. Alexis says.
For example, if a woman straightens her hair using heat, “any exposure to water will revert the hair from straight to curly again,” Dr. Alexis says. “Hence, recommending daily washing with a medicated shampoo would not be compatible with that person’s usual haircare practices and could potentially lead to hair breakage and dryness.”
Instead, Dr. Alexis recommends a once-weekly washing with a medicated shampoo.
“To compromise for that less frequent shampooing, there are topical products that the patient can leave on [her] scalp that are effective for psoriasis,” he says.
One such daily product is a two-compound scalp formulation containing calcipotriene and betamethasone diproprionate (Taclonex, Leo Pharma).
“This topical suspension also has castor oil in its vehicle, which is very well suited for this hair type and is widely accepted by patients in this population,” Dr. Alexis says. “It was also specifically used in studies in black and Latino patients with scalp psoriasis.”
In addition to the scaling, redness and thickness of psoriasis plaque that is found in all patient populations, darker skin types face the added burden of pigmentary alteration.
“Once the psoriasis resolves, it tends to leave postinflammatory hyperpigmentation or postinflammatory hypopigmentation,” Dr. Alexis says. “This lasts for many months after the psoriasis is cleared, thus delaying the total clearance of the skin during treatment by three months to six months, depending on the overall severity.”
Quality of life
Such a bleak outlook “very likely contributes to the more adverse quality-of-life impact that has been observed in this population,” Dr. Alexis says.
“Thankfully, we now have a much larger range of treatment options for all of our psoriasis patients,” Dr. Alexis says. “But one should avoid undertreatment of psoriasis in darker skin types, given the risk of pigmentary sequelae that can last many weeks after a psoriasis plaque heals.”
Patients also need to be informed of a realistic timeline for pigmentation to resolve.
“There are instances where we may need to use a skin-lightening agent like hydroquinone to treat the residential hyperpigmentation that is left behind after a psoriasis plaque resolves,” Dr. Alexis says.
Early and effective treatment, including use of systemic and biologic agents to adequately control the inflammatory disease, “will not only help to address the scaling and the elevation and redness of the plaques, but also will likely reduce the severity and extent of pigmentary abnormalities that these patients face,” Dr. Alexis says.
A larger healthcare landscape issue, however, is that non-white racial ethnic minorities in the United States are less likely to visit a specialist for skin conditions, including psoriasis, according to some studies.3
“These heath disparities that do exist contribute to delays in diagnosis of psoriasis,” Dr. Alexis says.
Disclosure: Dr. Alexis has served as an investigator for Dermira and Novartis.
1. Shah SK, Arthur A, Yang YC, Stevens S, Alexis AF. A retrospective study to investigate racial and ethnic variations in the treatment of psoriasis with etanercept. J Drugs Dermatol. 2011;10(8):866-72.
2. McMichael A, Alexis A. Efficacy and Safety of Brodalumab in Patients with Moderate-to-Severe Plaque Psoriasis and Skin of Color. Poster Presentation at the 2017 Skin of Color Seminar Series, New York, NY
3. Kurd SK, Gelfand JM. The prevalence of previously diagnosed and undiagnosed psoriasis in US adults: results from NHANES 2003-2004. J Am Acad Dermatol. 2009;60:218-224.