Diagnosing psoriasis in darker skin types
Dr. Andrew F. Alexis of New York City explains how to diagnose psoriasis in Fitzpatrick skin types V and VI
As part of his talk on psoriasis in skin of colour at Skin Spectrum Summit 2019, Dr. Andrew F. Alexis detailed a number of ways that the condition can present differently in darker skin. His comments were part of a larger talk debunking myths surrounding the prevalence of psoriasis in darker skin and comparing the disease’s colour presentation and shape across skin shades.
He began his talk by discussing how psoriasis in darker skin has come to be understood better over the years. Although it was once considered a “rare” skin condition in people of colour, Dr. Alexis debunked that myth.
“This was due to underreporting,” he said. “Thankfully, more recent studies have shown that the prevalence of psoriasis in darker skin is far from rare; in fact, these studies have shown the prevalence rate [to be] in the one to two per cent range.”
Dr. Alexis said that sometimes the presentation is classic; it is usually sharply demarcated, brick red or pink, and can have plaques with silvery scales.
“However, once we get into the more darkly pigmented ranges of the spectrum, including Fitzpatrick type V and type VI, the redness may be masked by melanin and may start to look a little more purple or violaceous than red,” he said.
The sharp lines of demarcation and the characteristic scale will still be present, he said, but because of the purplish hue, it can be difficult to distinguish from linchen planus, another papulosquamous disorder.
One factor that can help differentiate the two disorders is the location on the body where it is found.
“Lichen planus tends to favour the flexural side of extremities, including the wrist and forearm, while psoriasis will be more extensor,” he said.
The shapes of the lesions of the two disorders differ as well, he said. “In lichen planus, plaques tend to be more flat-topped and polygonal.”
Hyperpigmented lesions ranging from dark brown to red-brown may appear on darker skin as opposed to red lesions on lighter skin.
Certain skincare practices may also hide the character of the scale. In his presentation, Dr. Alexis gave the example of a patient who had a nightly routine of applying petrolatum ointment on his scaly plaques and scraping off the scales with a kitchen knife.
The takeaway: “This is a lesson to be learned as far as asking about what patients are doing and considering how that might impact the clinical appearance of the plaques in front of us,” said Dr. Alexis.
FROM THE LITERATURE ON PSORIASIS IN SKIN OF COLOUR
Psoriasis in patients of colour: Differences in morphology, clinical presentation, and treatment: A review of etiology, prevention, and treatment
A number of differences exist between psoriasis in lighter skin and psoriasis in skin of colour, including morphology, appearance, treatment, and sociocultural factors. Investigators suggested that medical training and continuing education programs include a focus on these differences.
A review of current phase III clinical trials of plaque psoriasis: under-representation of nonwhite participants and need for reform
In a review of current phase III clinical trials of plaque psoriasis, researchers found that nonwhite participants were underrepresented. Researchers called for reform to trial recruiting protocols.
Content analysis of psoriasis and eczema direct-to-consumer advertisements
In a review of 40 TV direct-to-consumer advertisements for psoriasis and eczema products, researchers found that the vast majority of actors were white. In psoriasis commercials, 94% of the characters portrayed were white, while in eczema commercials, 54% were white.
AT THE INTERSECTION OF SKIN & SOCIETY
The owner Black Girl Sunscreen, a sun protection brand, has recently raised $1 million dollars (USD) in investment capital, according to a recent article in Forbes. The brand, which is carried at Target stores in the U.S., raised the money after launching an effective sales campaign promoting sun protection for all skin types. Despite the pandemic, owner Shontay Lundy (pictured below), rallied her team, telling the business magazine Forbes “I told the team we need to change the narrative and be very nimble to survive this." Read the full article here.
Monday, Oct. 19, National Psoriatic Arthritis Day
Wednesday, Oct. 21, National Pharmaceutical Congress (an annual conference for the life sciences industry organized by Chronicle Companies)
Monday, Oct. 19 - Oct. 20 Orthopedics and Rheumatology World Forum
Something to think about during the week ahead…
A presentation by Dr. Monica Li on underreported, underdiagnosed rosacea in patients with skin of colour. Subscribe to Skin Spectrum Weekly and have each issue sent directly to your phone or inbox.
Thank you to our panellists and delegates for making Skin Spectrum Summit 2020 a great success. Conference highlights will soon be posted to the Skin Spectrum website.