Genetic contributions to racial HS prevalence
Mutations in enzyme-producing genes, variations in apocrine gland size and distribution may be factors, but more research is needed (1,500 words, 7 minutes 30 seconds)
Hidradenitis suppurativa (HS) may affect skin of colour patients differently because of genetic factors, Dr. Raed Alhusayen told delegates to the 9th annual Skin Spectrum Summit. However, he noted much of the information on these topics is limited and from old studies.
Dr. Alhusayen is an assistant professor in the Division of Dermatology at the University of Toronto, an associate scientist at the Odette Cancer Research Program and a staff physician in the Division of Dermatology at Sunnybrook Health Sciences Centre and Women’s College Hospital.
There are probably more questions than answers about genetic factors contributing to HS prevalence in different skin types due to a lack of research in this area, Dr. Alhusayen said. The data that is available is primarily from Chinese patient populations and shows that roughly 7% of those with familial HS have mutations in the presenilin genes, which are responsible for the gamma secretase enzyme. This is the same enzyme implicated in Alzheimer’s disease. It is unclear if patients with familial HS have a higher risk of Alzheimer’s. Studies from the U.S. show no link, but those studies would not capture this population, said Dr. Alhusayen.
Data from the 1960s shows that Black patients in general have larger and more numerous apocrine glands, said Dr. Alhusayen. Whether HS is a disease of the apocrine glands or of hair follicles, it is known to be more common in apocrine gland-rich areas, such as armpits or groin. Because this is old data, it may be unreliable, he advised.
Bottom line: There is limited and outdated research on the potential role of genetics in differences in HS prevalence by skin type. What does exist suggests that mutations in presenilin genes found in some populations may contribute to familial HS. Genes that guide the size and distribution of apocrine glands may also play a role in HS.
From the literature on hidradenitis suppurativa
Prevalence of hidradenitis suppurativa in an African population: Validation of a screening questionnaire in Lagos, Nigeria
This cross-sectional study included 802 healthy adults accompanying their relations to the outpatient clinic of Family Medicine and Ophthalmology at the Lagos State University Teaching Hospital in Lagos, Nigeria, following ethical approval. The study was conducted using a validated screening questionnaire for hidradenitis suppurativa (HS). Screen-positive and randomly selected screen-negative participants were clinically examined. The researchers used the Hurley score to categorize severity.
The prevalence of HS in the sample was 2.2% (18/802; 95% CI: 1.4-3.5%) with no gender predominance. The mean age in the HS group was 34 years (IQR 28-42) and the median body mass index (BMI) of the HS patients was 27.0 (IQR 21.4-28.6). Researchers found no significant difference in BMI between the HS and control groups. The screening questionnaire had a sensitivity of 1 (18/18), a specificity of 0.8 (20/25), a positive predictive value of 0.8 (18/23), and a negative predictive value of 1 (20/20). The axilla was the predominant site of affection (66.7%), and all HS patients were classified as mild disease (Hurley score 1).
Efficacy and durability of intravenous ertapenem therapy for recalcitrant hidradenitis suppurativa
Researchers retrospectively reviewed the medical records of 98 patients with HS between 2018 and 2022 and measured and evaluated patient outcomes before and after treatment with intravenous ertapenem.
The self-reported racial distribution included three individuals identifying as Asian (3.1%), 59 as Black/African American (60.2%), 13 as White (13.3%), and 23 as either other or unknown (23.5%). Additionally, 24 participants (24.5%) reported Spanish/Hispanic/Latino ethnicity.
Patients were treated with 1 g of ertapenem that was self-administered at home through a peripheral intravenous central catheter using an elastomeric pump for 12 to 16 weeks. Antiandrogens and immunomodulatory biologic therapies initiated before ertapenem were maintained throughout the treatment course.
From baseline to posttherapy follow-up, investigators found significant reductions in the mean (SD) HS Physician Global Assessment scores (3.9 [1.0] vs 2.7 [1.2]; p<0.001) and the numerical rating scale for pain (4.2 [3.3] vs 1.8 [2.7]; p<0.001), C-reactive protein (5.4 [11.4] vs 2.4 [2.0] mg/dL; p<0.001), interleukin-6 (25.2 [21.1] vs 13.7 [13.9]; p<0.001), and leukocytes (11.34 [3.9] vs 10.0 [3.4]; p<0.001). At follow-up, 76 patients (78.0%) participated in the telephone survey, where 63 (80.3%) reported medium to high satisfaction; further, 69 (90.8%) would recommend ertapenem to other patients.
Treatment of Hidradenitis Suppurativa Evaluation Study: the THESEUS prospective cohort study
Researchers aimed to understand the current hidradenitis suppurativa management pathways and what influences treatment choices to inform the design of future randomized controlled trials.
Investigators recruited 151 participants between Feb. 2020 and July 2021. The baseline demographics included an average age of 36 years, 81% female, 20% black, Asian, or Caribbean, 64% current or ex-smokers, and 86% with a raised body mass index.
The primary outcome was the proportion of participants who were eligible, and hypothetically willing, to use the different treatment options.
Treatments recorded included oral doxycycline 200 mg once daily; oral clindamycin and rifampicin, both 300 mg twice daily for 10 weeks initially; laser treatment targeting the hair follicle (neodymium-doped yttrium aluminum garnet or alexandrite); deroofing; and conventional surgery.
Some 69% of patients had moderate disease, 19% had severe disease and 13% had mild disease. Laser treatment had the highest proportion (69%) of participants who were eligible and hypothetically willing to receive treatment, followed by deroofing (58%), conventional surgery (54%), the combination of oral clindamycin and rifampicin (44%) and doxycycline (37%). Considering participant willingness in isolation, the laser was ranked the first choice by the greatest proportion (41%) of participants. The cohort study and qualitative study demonstrated that participant willingness to receive treatment was strongly influenced by their clinician. Fidelity to oral doxycycline was only 52% after three months due to lack of effectiveness, participant preference and adverse effects. Delays in receiving procedural interventions were common, with only 43% and 26% of participants commencing laser therapy and deroofing, respectively, after three months. Treatment switching was uncommon and there were no serious adverse events. Daily pain score text messages were initiated in 110 participants. Daily responses reduced over time with the greatest concordance during the first 14 days.
Quantitative sensory testing to characterize sensory changes in hidradenitis suppurativa skin lesions
This cross-sectional study explored the hypothesis that patients with hidradenitis suppurativa (HS) would demonstrate hypersensitivity to pain in HS lesions and that some patients would have sensory profiles consistent with complex pain mechanisms.
Researchers enrolled adults with dermatologist-diagnosed HS and at least one painful HS lesion at the time of testing between Sept. 10, 2020, and March 21, 2022.
This study included 20 participants with a median age of 35.5 years, the majority of whom were women (15 [75%]). Two participants (10%) self-identified as Asian, 11 (55%) as Black, six (30%) as White, and one (5%) as more than one race or ethnicity. Compared with site-specific reference values from healthy, pain-free control participants, researchers found HS lesions were insensitive to innocuous cold and warmth, noxious heat, and light touch (t=-5.69, -10.20, -3.84, and 4.46, respectively; all p<0.001). In contrast, they found HS lesions also demonstrated significant hypersensitivity to deep pressure pain (t=8.36; p<0.001) and cutaneous pinprick (t=2.07; p=0.046). Hypersensitivity to deep pressure pain was also observed in the control site (t=5.85; p<0.001). A subset of patients with HS displayed changes in pain processing that are often seen in neuropathic and nociplastic pain conditions, including hypersensitivity to repetitive pinprick (5 [26%]), paradoxical thermal sensations (3 [15%]), and pain upon light stroking of the skin (10 [50%]).
VIDEO: Dr. Julia Riley discusses racial disparities in hidradenitis suppurativa
Dermatologist Julia Riley, MD, of Northwestern Medicine, Chicago, discusses how hidradenitis suppurativa is characterized and treated, why it disproportionately impacts people of colour (specifically Black and bi-racial people), disparities in clinical trials, and more.
At the intersection of skin and society
As reported in The Globe and Mail newspaper, the Supreme Court of Canada ruled self-governing Indigenous communities have a collective right to protect their cultural differences that trumps individual rights guaranteed by the Canadian Charter of Rights and Freedoms (Mar. 28, 2024).
According to the news outlet, the court was ruling in a case involving the Vuntut Gwitchin First Nation in Yukon, which has been self-governing since 1993. The fly-in community has fewer than 1,000 members, of whom just 280 live on its traditional lands. Anyone wishing to be a member of its elected council is required to live on those lands. Cindy Dickson, a citizen of the Vuntut Gwitchin who lives 800 kilometres to the south, in Whitehorse, challenged the residency requirement under the Canadian Charter’s Section 15, which protects the right to equality.
The question before the court was whether the Charter’s Section 25, which protects Indigenous collective rights—has primacy over individual rights, The Globe reported.
Six of the seven judges who heard the case said the Charter applies, with Justice Malcolm Rowe as the only dissenter. Of the six who said the Charter applies, four said Section 25 trumps other Charter rights in certain circumstances, and two disagreed.
The two who disagreed, including the lone Indigenous judge Justice Michelle O’Bonsawin, an Abenaki member of the Odanak First Nation, said Section 25’s purpose was to protect against claims by non-Indigenous people that benefits for Indigenous Canadians were discriminatory under Section 15’s equality provisions. The section was not intended to protect against claims made by Indigenous individuals.
This week
April is Arab American Heritage Month in the U.S.
April is Rosacea Awareness Month
April 14 is World Chagas Disease Day
The week of April 14 is Pan-American Week
Something to think about in the week ahead. . .
—Pablo Picasso, Spanish painter (1881-1973)
Next week
Dr. Renée Beach speaks on central centrifugal cicatricial alopecia and an emerging therapy to treat it.
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