Genetic and immune differences in darker skin lead to misdiagnosis of AD
Patients may face delays in specialist referrals when physicians underestimate atopic dermatitis severity in their skin type (1,600 words, 8 minutes)
Variations in genotype and immune reactivity between skin types contribute to differences in the presentation of atopic dermatitis (AD) in darker skin, Dr. Marissa Joseph told the 2024 Summit on Atopic Dermatitis on May 11. Lack of recognition of AD in these patients can then lead to underestimation of disease severity, delays in diagnosis, and underrepresentation in medical education and clinical trials.
Dr. Joseph is a full-time academic faculty at the University of Toronto and medical director of the Ricky Kanee Schachter Dermatology Centre at Women's College Hospital.
She said it is important to consider clinical phenotypes of AD, particularly across bioancestral backgrounds, because there are genotypic and immune typing differences across these backgrounds.
Dr. Joseph cited a study (Czarnowicki T et al: J Allergy Clin Immunol 2019; 143(1):1-11) showing differences in immune polarization and skewing of TH17 and TH1 in African-American and Asian-American patients. There are also differences in the epidermal barrier and the representation of different proteins.
These underlying differences produce differences in presentation, she said. Patients with darker skin tones are far more likely to have erythema that is violaceous, greyish, reddish-brown, or dark brown. They are also more prone to post-inflammatory dyspigmentation, follicular accentuation, or papular eczema. In patients with darker skin, AD is more likely to present on extensor areas, such as elbows or knees, rather than flexural areas.
Physicians unfamiliar with these differences may fail to assess AD severity in some patients.
Dr. Joseph compared two patients who had been referred to her. One was light-skinned with reddish erythema over at least 80% of the body. Such patients are often referred to dermatologists as severe eczema cases that need to be seen urgently, she said.
In contrast, the referral for a Black patient noted simply dry skin, even though the patient had endured a long wait to be seen and had significant school issues. The patient also had extensive skin involvement and required dedicated treatment but faced a delay because the severity of his symptoms had been underestimated.
Dr. Joseph said that changing the definition of symptoms such as erythroderma in diagnostic guidelines may help provide language to quantify the severity of a patient's condition regardless of skin type.
Bottom line: Underlying differences in genotype and immune reactivity drive variations in AD presentation among skin types. Practitioners who lack an understanding of these differences can delay referrals to dermatologists.
From the literature on atopic dermatitis
The impact of phototherapy on itch intensity and itch-related quality of life amongst different skin diseases, skin phototypes and genders—A prospective study with 102 patients
In this prospective, single-center study, researchers analyzed the effect of phototherapy on itch intensity and itch-related quality of life. They observed that patients with pruritus on non-diseased skin reported the most significant improvement in itch intensity and itch-related QoL, followed by patients with atopic dermatitis and psoriasis.
The study involved 102 patients with a range of skin diseases, phototypes, and genders who were treated with phototherapy for four weeks. On-demand treatment with topical corticosteroids, topical calcineurin inhibitors, or antihistamines was allowed.
Of the participants, 72 (78.3%) reported a significant reduction of itch intensity (-2.76 on a 0-10 Numerical Rating Scale (NRS), p=0<0.001, 95% CI [2.2; 3.3]). This reduction was paralleled by a significant improvement in itch-related quality of life as measured by the German version of the ItchyQoL (Δ 7.3, p=0<0.001, 95% CI [4.4; 11.6]).
Patients with pruritus on non-diseased skin reported an improvement of itch intensity and itch-related QoL of ΔNRS -3.5; Δ9.7 Ger-ItchyQoL points).
Researchers observed no statistical differences in the response to phototherapy amongst Fitzpatrick phototypes I-VI. Women had higher itch intensities at baseline, but itch-related quality of life impairment at baseline and phototherapy treatment response did not significantly differ between genders.
Image analysis of xerosis and atopic dermatitis following prebiotic skincare regimen in ethnically diverse patients
This study evaluated the capability of a new imaging device (SkinCam) in quantifying skin texture changes in diverse patients presenting with atopic dermatitis (AD) or xerosis after using a prebiotic skincare routine over ten weeks.
Researchers enrolled 39 subjects aged three to 76 from diverse racial and ethnic backgrounds and Fitzpatrick skin phototypes I to VI. All subjects presented with mild AD and moderate to severe xerosis. Participants used a prebiotic cleanser on its own for two weeks, followed by a prebiotic moisturizer in conjunction for an additional eight weeks. Investigators took standardized images of the subjects' legs with SkinCam at baseline, week two, and week ten and analyzed the photos for skin texture parameters.
The authors conclude that the findings demonstrate that both skin texture irregularity and skin colour patterns significantly improve over time with a prebiotic skincare regimen in AD (n=12) and xerosis (n=24) subjects. They note that the image analyses improved over time in skin-of-color patients (n=18, Fitzpatrick IV-VI). The skin texture analyses from SkinCam imaging also correlated with clinical assessments, showing significant improvement by prebiotic skincare regimen in all subjects by week 10.
Ethnic and racial disparities in clinical manifestations of atopic dermatitis
This open-access, critical review article provides an overview of the current findings on the epidemiology of atopic dermatitis, including ethnic and racial disparities.
Topics covered include:
Clinical cutaneous manifestations
Extra-cutaneous clinical manifestations
Epidemiology of atopic dermatitis in diverse racial and ethnic groups
Presentation of atopic dermatitis in skin of colour
Genetic manifestations of atopic dermatitis in different racial groups
In their conclusions, the authors write their findings hold potential significance in advancing the development of targeted treatments for personalized medicine approaches and enhancing the quality of life for patients with atopy.
Validation of the Recap of atopic eczema (RECAP) measurement instrument for eczema control in adult patients in an Asian clinical setting
Researchers assessed the utility of the Recap of atopic eczema (RECAP) self-reported seven-item initiative to measure eczema control in a patient population in Singapore.
In their analysis, the investigators included 260 patients with atopic eczema, aged between 15 and 87 years, from Singapore’s National Skin Centre from July 2019 to Jan. 2020. Their correlation analysis used both patient- and physician-reported outcome measures. They also performed correlation analysis to investigate construct validity and floor or ceiling effects of RECAP.
They note RECAP is recommended by the Harmonising Outcome Measures in Eczema initiative.
Researchers found minimal floor and ceiling effects on RECAP scores. There were strong, significant correlations of RECAP with Patient-Oriented Eczema Measure (r=0.84, p<0.001) and Dermatology Life Quality Index (r=0.81, p<0.001). Correlation with SCORAD (SCORing Atopic Dermatitis) was moderate (r=0.60, p<0.001). The authors note these correlations remained similar after age, gender, and ethnicity adjustments. Discriminative validity was demonstrated by a significant linear trend of increasing RECAP scores and eczema severity. They conclude that RECAP demonstrates good discriminative and construct validity, as evidenced by strong correlations with symptoms and quality of life and moderate correlations with eczema signs. Because of this, RECAP helps measure eczema control in Singapore.
VIDEO: Eczema and acne in skin of colour
In a talk originally given at the 2023 British Association of Dermatologists annual meeting, dermatologist Dr. Paul Yesudian (Chester, U.K.) discusses atopic dermatitis biology, diagnosis and management in skin of colour. This talk also discusses acne, tinea versicolor, and squamous cell carcinoma.
Nominations for 2024 Women in Dermatology Honour Roll closing soon
The 2024 Women in Dermatology Honour Roll nomination deadline is July 26, 2024.
This Honour Roll acknowledges the leadership of a select group of Canadian physicians. It recognizes female dermatologists in Canada who have made significant contributions to the specialty, inspire others and serve as mentors and role models.
The 2024 honourees will be profiled in the upcoming Third Edition of Women in Dermatology, from the publishers of The Chronicle of Skin & Allergy.
Nominees should be female dermatologists who, throughout their careers, have made a lasting impact on others in the field of dermatology, served as a source of inspiration to residents, colleagues, and patients, and demonstrated extraordinary dedication, leadership, and commitment to the principles of dermatologic care.
To learn more or to obtain a nomination form, please go to the following link:
At the intersection of skin and society
The Canadian Skin Patient Alliance (CSPA) announced Dr. Rachel Asiniwasis as their 2023 Dermatologist of the Year during the Canadian Dermatology Association’s annual conference on July 28.
Dr. Asiniwasis, who has Plains Cree and Saulteaux ancestry on her father’s side, was recognized for her incredible dedication to patients and families in her home region of Regina and the remote and northern Indigenous communities she and her small team have made it their mission to serve.
The CSPA is a registered charity that works to improve the health and well-being of people across Canada affected by skin, hair, and nail conditions.
“One of [Dr. Asiniwasis’] passions is learning about the health care challenges faced by remote populations and First Nations and developing proactive approaches to address these challenges within the framework of Truth and Reconciliation,” a post by the CSPA reports. “To better understand and represent these communities, she returned to school to pursue a master's degree in health sciences in clinical and translational research. She hopes that her work can be used better to inform regional and national priorities for Indigenous skin health. “
This week
July 10 is Chronic Disease Day in the U.S.
July 11 is World Population Day
July 12 is Malala Day, in honour of Nobel Peace Prize recipient Malala Yousafzai.
Something to think about in the week ahead. . .
—Phoebe Cary, U.S. poet (1824-1871)
Next week
A paper published in Advanced Biomedical Research shows the value of dermoscopy for differentiating superficial basal cell carcinomas from other basal cell carcinomas in skin of colour.
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Drs. Andrei Metelitsa (Calgary), Geeta Yadav (Toronto), and Rahul Shukla (Hamilton, Ont.) review several current innovations in cosmetic dermatology.
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