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Acta Derm Venereol
Acta Derm Venereol
ActaDV
Acta Dermato-Venereologica
0001-5555
1651-2057
MJS Publishing, on behalf of the Society for Publication of Acta Dermato-Venereologica

39193931
ActaDV-104-41138
10.2340/actadv.v104.41138
Short Communication
The Nationwide Epidemiology of Patients Treated for Hidradenitis Suppurativa by a Dermatologist in the Faroe Islands
BROSBØL Amanda T. 1*
BOUAZZI Dorra 12
JEMEC Gregor B.E. 123
SAUNTE Ditte M.L. 123
1 Department of Dermatology, Zealand University Hospital, Roskilde, Denmark
2 Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
3 Dermatology Clinic, Landssjukrahusid, Tórshavn, Faroe Islands
* E-mail: amandatbrosboel@gmail.com
28 8 2024
2024
104 4113807 7 2024
29 7 2024
© 2024 The Author(s)
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License
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pmcHidradenitis suppurativa (HS) is a chronic inflammatory skin disease (1). Patients develop painful suppurating nodules and/or abscesses, always located in the axillary, inguinal, peri-genital, and perineal regions. The disease can progress and lead to scarring and the formation of tunnels (2). Studies have shown a correlation with the severity of HS and obesity and smoking (3). The diagnostic delay in HS diagnosis is 7.2 years globally (4). The diagnostic delay results in delayed treatment initiation.

The worldwide prevalence of HS has been estimated to be 0.0003–4% (4). The prevalence of HS in the Faroe Islands is unknown. This study was undertaken to estimate the population-based prevalence of HS, and to describe the epidemiology of HS patients in the Faroe Islands.

MATERIALS AND METHODS

The study was conducted as a retrospective registry-based study including HS patients registered in the Telemedicine patient records system (Danish Telemedicine, Copenhagen, Denmark) from the dermatological outpatient clinic, Landssjukrahusid, Torshavn, Faroe Islands during a period from 2007–2022. Patients registered in the Telemedicine system are referred from general practitioners. We included demographic information, HS-specific data, and treatment-related data. In cases where no Hurley stage was recorded and photos of the lesions were available, the Hurley stage was identified by (DB & DMS) using the Hurley classification. The predefined data were extracted into an Excel spreadsheet by two investigators (AB & DB) separately for quality control. The prevalence of HS in the Faroe Islands was calculated based on a total population of 48,865 persons (data from 2020) (5).

RESULTS

A total of 45 individuals were diagnosed with HS. The prevalence of HS in the Faroe Islands is therefore 0.9% (45/48.865; CI 0.69–1.2). The majority (78%) of the HS patients were women. The median age at first contact was 33 years (IQR 25–46). Sixteen (36%) individuals were currently smoking. The mean ± standard deviation BMI of the HS population was 34.1 ± 4.48. Areas of the skin affected indicated the axilla and the groin as the most common areas. Most patients (84%) were affected in multiple anatomical areas. Twenty-three (51%) medical records had data regarding a diagnostic delay, which was calculated to be a median of 10 years (IQR 5–25).

Twenty-one (47%) of the patients had received treatment before diagnosis. The most common past treatment for HS was systemic antibiotic therapy. All patients, except one, had been treated with a topical treatment after diagnosis. The majority (78%) had received systemic treatment after diagnosis, with systemic antibiotics being the most common. Tetracyclines (doxycycline and tetracycline) represented 60% of the patients being treated with antibiotics. See Table I for more information.

Table I Demographic data, clinical data, and treatment (n=45)

Sex, n (%)		
 Male	10 (22)	
 Female	35 (78)	
Age at first contact in years, median (IQR)	33 (25–46)	
Smoker, n (%)		
 Yes	16 (36)	
 No	4 (9)	
 Ex-smoker	3 (7)	
 Not assessed	22 (49)	
Hurley stage, n (%)		
 I	11 (24)	
 II	29 (64)	
 III	2 (4)	
 Not assessed	3 (7)	
Body mass index, mean (SD)	34.1 (4.48)	
 Not assessed	32 (71)	
Anatomic location – areas affected, n (%)
 Groin
 Axil	
36 (80)
30 (66)	
 Mamma	14 (31)	
 Pubis	12 (26)	
 Abdomen	8 (17)	
 Nates	7 (15)	
 Anus
 Genitalia
 Other
Patients with more than one affected area (%)	6 (13)
4 (8)
3 (6)
38 (84)	
Diagnostic delay, years, median (IQR)
 Not assessed, n (%)	10 (5-25)
22 (49)	

	Patients, n (%)	Drug	Patients, n (%)*	
Treatment before diagnosis		
Yes
No	21 (47)
24 (53)	Antibiotics
 Tetracycline (systemic)
 Antibiotics (not specified)
 Fucidin (topical)
 Clindamycin (systemic)
 Erythromycin (systemic)
 Clindamycin (topical)
Disinfectants
 Chlorhexidine gluconate (topical)
Other
 Azelaic acid (topical)
 Contraceptive pill (systemic)	
7 (16)
6 (13)
3 (7)
1 (2)
1 (2)
1 (2)

2 (4)

1 (2)
1 (2)	
Treatment after diagnosis – topical		
Yes
No	44 (97)
1 (2)	Antibiotics/combined antibiotics
 Clindamycin
 Benzoyl peroxide/clindamycin
 Clindamycin/tretinoin
Disinfectants
 Chlorhexidine gluconate
Other
 Azelaic acid
 Resorcinol
 Triamcinolone acetonide
 Hydrocortisone	
30 (67)
1 (2)
1 (2)

1 (2)

26 (58)
22 (49)
11(24)
1 (2)	
Treatment after diagnosis – systemic		
Yes
No	35 (78)
10 (22)	Antibiotics
 Tetracycline
 Combination of rifampicin & clindamycin
 Doxycycline
 Amoxicillin/clavulanic acid
 Roxithromycin
Other
 Metformin
 Dapsone
 Adalimumab
 Acitretin
 Contraceptive pill	
22 (49)
13 (29)
5 (11)
2 (4)
1 (2)

11 (24)
2 (4)
1 (2)
1 (2)
1 (2)	
	
Overall number of shifts in systemic treatment, n (%)	
Median (IQR)
Shift
No shift
Not on systemic treatment
Lost to follow-up	1 (0-1)
18 (40)
7 (16)
11 (24)
9 (20)	
	
Surgical treatment after diagnosis, n (%)	Surgical procedure	Patients, n (%)*	
	
Yes: 6 (13)
No: 39 (87)	CO2
Deroofing	4 (9)
2 (4)	
	ID/excision	2 (4)	
IQR: interquartile range; SD: standard deviation; ID: incision and drainage.

* Administered to n of patients (%). Some patients had multiple treatments.

DISCUSSION

Our study has several limitations that need to be considered. First, selection bias might be present in our cohort as only patients referred to a dermatologist by a general practitioner are included in this study. Patients with mild HS might not consult a general practitioner or the consulted practitioner might not refer them to a dermatologist. Second, the medical records were lacking essential data such as BMI and smoking for multiple patients. BMI was not assessed in 32 (71%) of the patients, and data on smoking were lacking in 22 (49%) records. The lack of data prohibited us from correctly characterizing all HS patients. However, a strength of our study is that the results represent all patients in the Faroe Islands seen by a dermatologist and registered under the diagnosis of HS.

Finally, this study is the first prevalence study to be undertaken on the population of the Faroe Islands. The prevalence of HS in the Faroe Islands is an important tool to create awareness of the disease, with the goal of reducing the diagnostic delay and initiate treatment.

Conflict of interest disclosures

DB: UCB Nordic paid for EADV Congress 2022 participation. GBEJ has received honoraria from AbbVie, Chemocentryx, Coloplast, Incyte, Inflarx, Novartis, Pierre Fabre, and UCB for participation on advisory boards, and grants from Abbvie, Astra-Zeneca, Inflarx, Janssen-Cilag, Leo Pharma, Novartis, Regeneron, and Sanofi for participation as an investigator, and received speaker honoraria from AbbVie, Boehringer-Ingelheim, Galderma, and MSD. He has also received unrestricted departmental grants from Abbvie, Leo Pharma, and Novartis. DMLS reports personal fees from UCB, AbbVie, Janssen, Jamjoom Pharma, and Sanofi, grants and personal fees from Abbvie, Leo Pharma, Pfizer, and Novartis outside the submitted work.
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5 Population, total - Faroe Islands | Data. Available from: https://data.worldbank.org/indicator/SP.POP.TOTL?end=2021&locations=FO&start=1960
