Genetics, skin manifestations of AD in skin of colour
Common education on genetic causes and presentation of AD may not accurately reflect the reality in different skin types (1,300 words, 6 minutes)
Skin Spectrum Weekly is published with unrestricted support from Bausch Health Canada
The Hanifin and Rajka criteria for diagnosis of atopic dermatitis (AD) do not necessarily reflect how AD presents in all skin tones, said Dr. Renée Beach during a presentation at the 8th annual Skin Spectrum Summit in Sept. 2022. She also noted that filaggrin mutations are often taught as a common cause of the condition, though other mutations may be responsible in some populations.
The Hanifin and Rajka criteria, developed in the early 1980s, list both major and minor traits of AD, Dr. Beach said. She said some minor criteria make sense across all skin tones and skin types, such as itching when sweating and food intolerance. “However, [the criteria] did make a couple of assumptions, such as facial pallor or facial erythema, and certainly white dermographism or delayed blanching does not capture the full spectrum of skin tones and skin types that we encounter daily.”
Dr. Beach listed several morphological presentation criteria she said should be used to identify AD in patients with skin tones ranging from Olive to Black. These include:
Lichenification
Leukoderma
Flaking—often mistaken for a fungal infection or tinea corporis
A nummular presentation of lesions
A more violaceous hue, rather than reddening
Prurigo nodules
Hyperpigmentation
Dr. Beach said that the immune system aspects of AD also vary by skin type. She noted there is more of a TH-17 and TH-22 response in Asian skin and more of a TH-17 and TH-1 response in Black skin.
“This is in contrast with a predominantly TH-1 response that we see in our patients with white skin.”
“Higher IgE [Immunoglobulin E] levels, which is a common feature for patients who are having a lot of itch, can be variable in the Asian population. But these levels are consistently elevated in our patients with Brown and Black skin,” she said.
She said the “ubiquitous” filaggrin mutations associated with AD are “not a huge presence in Asian skin. And in Black or African American skin in the literature, [filaggrin mutation] is found to have been six times less common. However, [mutations in] loricrin, which is a different type of skin protein, is found to be a more significant factor for our patients with Black skin.”
Bottom line: Many AD characteristics commonly taught as being universal to all skin types are not. Physicians and researchers should account for differences in AD between skin types.
From the literature on allergic disease in skin of colour
Allergic diseases in India—prevalence, risk factors, and current challenges
The authors of this narrative review note there is a high burden of atopic dermatitis, asthma, and allergic rhinitis in India. Unmet demand for trained allergy specialists and a poor health service framework compound this burden.
They discuss the wide variation in the prevalence of allergic diseases between different geographic locations in India and possible causes, including local differences in aero-biology, weather, air pollution levels, cultural and religious factors, diet, socioeconomic strata, and literacy.
Burden of allergic disease in racial and ethnic structurally oppressed communities within Canada and the United States: A scoping review
The authors conducted this scoping review of literature specific to structurally oppressed racial and ethnic populations to describe the burden of disease and access to health care for treating allergic diseases in these populations.
From an initial list of 1,198 potentially relevant articles, the authors included 12 articles. Those 12 studies pointed toward a higher burden of allergic and atopic disease, including increased presentations to emergency departments, hospitalizations, mortality, younger age of diagnosis, and greater severity of disease among Black or African American individuals than the general population.
Other than the top nine food allergens, eosinophilic esophagitis and asthma appeared to be more prevalent and severe in this population than in the general population.
The literature also showed there appears to be an increased burden of allergic and atopic disease among the Indigenous Peoples of Canada, not noted in Latinx or Hispanic populations. However, the authors note that may be partly due to only a small number of studies involving these populations. The investigators also pointed out that no conclusions regarding allergy and atopy in Native American populations could be drawn due to a lack of published literature.
Patient care and treatment strategies for skin diseases in Sub-Saharan Africa: Role of traditional and western medicines
This study reviews research into the general public's feelings about how the healthcare system in Sub-Saharan Africa (SSA) handles common skin conditions such as atopic dermatitis, Buruli ulcers, dermatophytosis, and scabies.
The authors note that the availability of medical care, socioeconomic factors, degree of education, and other factors influence patient attitudes toward traditional and western health care differently in different geographic areas.
A majority of patients were found to self-medicate before seeking dermatological care.
The researchers conclude that the magnitude of skin disease is neglected or underestimated in areas of SSA, and many healthcare facilities are inadequate.
Skin and nasal colonization of coagulase-negative staphylococci are associated with atopic dermatitis among South African toddlers
The authors of this paper note that skin colonization with coagulase-negative staphylococci (CoNS) is generally beneficial, but other research suggests it is associated with atopic dermatitis (AD) flares and severity.
This cross-sectional study included AmaXhosa toddlers with (cases) and without (controls) atopic dermatitis from the rural community of Umtata (now known as Mthatha) and urban Cape Town, South Africa.
The investigators collected CoNS from lesional and non-lesional skin and from inside the noses of the children.
They found that CoNS and S. aureus commonly co-colonized non-lesional skin cases (urban: 24% vs. 3%, p=0.037 and rural 21% vs. 6%, p<0.001), and in the nose in urban cases (24% vs. 0%, p=0.002) compared to the controls. S. capitis colonization on non-lesional skin and in the nose was positively associated with more severe disease in rural (48.3±10.8 vs. 39.7±11.5, p=0.045) and urban cases (74.9±10.3 vs. 38.4±13, p=0.004), respectively. Researchers noted that biofilm formation was similar between cases and controls, independent of rural-urban living.
VIDEO: Shared decision-making for atopic dermatitis & your healthcare team
At the intersection of skin and society
On Oct. 19, 2022, the Decolonizing the Narrative Conversation Series showcases Joely BigEagle-Kequahtooway, an interdisciplinary artist from White Bear First Nation in Saskatchewan.
Decolonizing the Narrative is a monthly online conversation series that invites leading Indigenous Art creators to talk about their practices and processes, according to the event’s website. The series is facilitated by Reneltta Arluk, Director of Indigenous Arts at the Banff Centre for Arts and Creativity in Banff, Alta.
In her talk, BigEagle-Kequahtooway will discuss how matriarchs have been the main inspiration in her artistic practice and research on buffalo and how important it is to acknowledge the past as one creates new futures.
“How will the next 1000 years be mapped out for Indigenous peoples?” is a question BigEagle-Kequahtooway seeks to answer through her art, according to a press release.
The talk will run from 4:30 to 5:30 MT on Oct. 19. A follow-up session for audience Q&A will occur on Oct. 20, 2022, from 4:30 to 5:30 MT.
Registration for the event is available at this link.
This week
October is Latin American Heritage Month in Canada
The third week of October is National Healthcare Quality Week in the U.S.
Oct. 17 is Black Poetry Day in the U.S.
Next week
During a virtual talk to mark National Day of Truth and Reconciliation on Sept. 30, 2022, Canadian Medical Association (CMA) President Dr. Alika Lafontaine spoke on “Decolonizing Healthcare.”
Dr. Lafontaine is the first Indigenous president of the CMA.
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