COVID‐19 in patients with hidradenitis suppurativa

Dear Editor, Information on hidradenitis suppurativa (HS) and COVID is scarce. HS is a chronic inflammatory cutaneous disease associated with comorbidities such as obesity, metabolic syndrome, smoking and cardiovascular disease, which are known to negatively affect COVID outcomes.¹, ²

This retrospective cohort study aimed to evaluate the outcomes of patients with HS who had confirmed COVID‐19. We used the Research Patient Data Registry, a clinical data registry from various Partners Healthcare System (PHS) affiliated hospitals in the Boston area. This area was highly affected between the months of March and May in 2020. As of 25 June 2020, of around 12 330 confirmed COVID cases in PHS, approximately 24·0%, 7·7% and 4·5% were admitted to hospital, a critical care unit and/or died, respectively.

Among more than 8000 patients who had a diagnosis of HS (International Classification of Disease 10th revision code L73·2) and more than 100 patients who were on biological therapy, we identified 58 patients with confirmed COVID‐19 (positive reverse‐transcriptase polymerase chain reaction) between 15 March and 25 May 2020. After reviewing their medical records on an electronic medical record system (Epic, Verona, WI, USA), we excluded 19 patients because HS could not be confirmed or was inactive for more than 3 years.

Demographic and clinical data are reviewed in Table 1. The majority of our patients with HS were female and of either Hispanic or African American race/ethnicity. They were relatively young and most were obese. Around one‐third of these patients had diabetes, hypertension and/or were past or current smokers. Overall, 26%, 44%, 23% and 8% of patients had involvement of one, two, three and four or more anatomical sites, respectively. The majority of patients were not on any current systemic treatment for HS when COVID was diagnosed. These patients had been treated with topical antibiotics or steroids, intralesional steroids, incision and drainage and/or local surgery, in addition to prior courses of systemic antibiotics that had been discontinued before diagnosis of COVID‐19.

Table 1.

Demographic and clinical characteristics of patients with confirmed COVID‐19 who had hidradenitis suppurativa (HS)

	Total (n = 39)	Not hospitalized (n = 31)	Hospitalized (n = 8)	P‐valuesa
Demographic data
Age (years)	42·1 ± 12·6	40·5 ± 10·9	48·0 ± 17·3	0·14
Female sex	31 (80)	27 (87)	4 (50)	0·04
Race/ethnicity
Black/African American	12 (31)	10 (32)	2 (25)
Non‐Hispanic				0·90
Asian, non‐Hispanic	1 (3)	1 (3)	0
White, non‐Hispanic	16 (41)	12 (39)	4 (50)
Hispanic	10 (26)	8 (26)	2 (25)
Clinical data
BMI (kg m−2)	34·4 ± 7·5	33·8 ± 7·2	36·9 ± 8·9	0·30
Current or past smoking	11 (28)	8 (26)	3 (38)	0·66
Diabetes	12 (31)	7 (23)	5 (63)	0·08
Hypertension	14 (36)	10 (32)	4 (50)	0·42
Asthma	11 (28)	8 (26)	3 (38)	0·66
Cardiovascular disease	5 (13)	3 (10)	2 (25)	0·27
Renal disease	1 (3)	0	1 (13)	0·21
Anxiety/depression	14 (36)	11 (36)	3 (38)	1·00
Pregnant	2 (5)	2 (7)	0	1·00
Current HS therapy
Biologic	1 (3)	1 (3)	0	1·00
Systemic antibiotic	7 (18)	4 (13)	3 (38)	0·14
Topical therapy	7 (18)	6 (19)	1 (13)	1·00
COVID outcomes
Supplemental oxygen			4 (10)
ICU admission			3 (8)
Orotracheal intubation			3 (8)
Death			1 (3)

BMI, body mass index; ICU, intensive care unit. ^aComparison between patients on any systemic therapy and nonsystemic therapy, using two‐sided Student’s t‐test or Fisher’s exact test for continuous and categorical variables, respectively. Data are presented as mean ± SD or n (%).

In terms of hospitalization, we found that more male patients required hospital admission. The proportions of patients within each ethnic group who required hospitalization were not significantly different [17% (two of 12) of African American patients, 20% (two of 10) of Hispanic patients and 25% (four of 16) of white patients]. Mean age, proportion of patients on systemic antibiotics for HS and diagnosis of diabetes were all increased in patients requiring hospitalization, but these trends were not statistically significant. Two patients who were pregnant (4 weeks and 18 weeks) had mild disease.

In our sample, eight patients were admitted to the hospital (for an average of 22 days, range 1–66). A 60‐year‐old patient died. He had hypertension, diabetes and peripheral artery disease. He was not on systemic treatments for HS. Rates of hospital and intensive care unit admission and death were not increased in our study sample when compared with the entire PHS population with confirmed COVID‐19 at that time. Only one patient was on a biologic (infliximab). He had mild COVID and did not require hospitalization. Patients received follow‐up calls for an average of 34 days (range 2–69) after the diagnosis of COVID.

There has been some debate on whether patients with HS would have an increased risk of severe COVID because of an overlap between comorbidities associated with HS and prognostic factors of COVID‐19.² An international registry has been developed in an attempt to collect more comprehensive data on HS severity, therapy and COVID‐19 outcomes.³ There has also been concern regarding potential racial disparities affecting COVID outcomes.², ⁴ In our sample, as expected, we had an increased proportion of patients of African American or Hispanic race/ethnicity; however, these patients did not have an increased risk of hospitalization. The only patient who died during our study was of older age, in addition to having other known risk factors for severe COVID.⁵

One Spanish study reported detailed data on eight patients with HS and suspected COVID‐19, including two patients on biological therapies. None of these patients were hospitalized or had poor COVID outcomes.⁶ An Italian survey of 96 patients with HS that was conducted by mail or phone call did not detect COVID‐related deaths or hospitalization.⁷ Although the risk factors for poor COVID outcomes, such as diabetes and hypertension, were more common among our patients, we feel that belonging to a younger age group protected patients with HS from a severe COVID outcome. Additional studies are required to confirm this finding.

Author Contribution

Xinaida Taligare Lima: Conceptualization (equal); Data curation (equal); Formal analysis (equal); Methodology (equal); Validation (equal); Writing‐original draft (lead). Mary A Cueva: Conceptualization (equal); Data curation (equal); Formal analysis (supporting); Validation (equal); Writing‐original draft (supporting); Writing‐review & editing (supporting). Maria Beatrice Alora: Conceptualization (equal); Data curation (equal); Formal analysis (supporting); Methodology (supporting); Project administration (equal); Supervision (equal); Writing‐review & editing (lead).