Abstract
Introduction
Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a diagnostic delay of 7–10 years. A later diagnosis is associated with development of local sequelae and systemic comorbidities, as well as a reduced response to medical treatment. The aim of this study was to analyze the time required for HS diagnosis and investigate factors associated with diagnostic delay.
Method
A retrospective observational study was conducted based on clinical records from HS patients followed at a tertiary hospital, with diagnosis between January 2006 and December 2022.
Results
A total of 285 patients were included. The mean diagnostic delay was 10.1 years, and there was no difference in time to diagnosis during the considered period. A diagnostic delay of more than 5 years was significantly associated with an earlier onset of symptoms, location on breasts and thighs, follicular phenotype, and with cardiovascular and psychiatric comorbidities. Smoking and body mass index ≥25 kg/m2 were also associated with a longer diagnostic delay. A personal history of acne and a greater disease severity were associated with an earlier diagnosis.
Conclusions
This study reveals the lack of improvement in the diagnostic delay in HS and highlights its association with atypical clinical manifestations and systemic comorbidities, scarcely reported in literature.
Keywords: Hidradenitis suppurativa, Diagnosis, Comorbidity
Introduction
Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the hair follicle that affects the apocrine gland-rich areas of the skin. It usually presents after puberty with recurrent painful nodules, abscesses, fistulas, and scarring on the intertriginous body areas [1]. Despite simple diagnostic criteria, HS remains widely undiagnosed, with available data suggesting a significant diagnostic delay of 7–10 years [2–7]. A later diagnosis leads to significant morbidity, not only due to the development of local sequelae and the association with systemic complications, but also because of a reduced response to medical treatment [2, 8]. With this study, the authors aimed to determine the time required for HS diagnosis and its evolution over time, as well as to investigate possible factors associated with diagnostic delay in patients observed at a Portuguese reference center for HS.
Materials and Methods
A retrospective observational study was conducted based on the analysis of clinical records from HS patients observed at a Portuguese HS clinic, with diagnosis between January 2006 (year of Dessau definition) and December 2022. According to Dessau definition, HS is a “chronic, inflammatory, recurrent, debilitating skin disease of the hair follicle that usually presents after puberty with painful, deep-seated, inflamed lesions in the apocrine gland-bearing areas of the body, most commonly the axillae, inguinal, and anogenital regions” [9].
The time required for diagnosis was established according to the patient reported age at symptom onset and diagnosis. Significant diagnostic delay was set at 5 years (the median time to diagnosis in the sample). Baseline clinical data were collected including: demographics, past medical history, age at onset of symptoms, family history of HS, body mass index, smoking status, affected body areas, and disease severity (International Hidradenitis Suppurativa Severity Score System – IHS4). Descriptive statistics were calculated to determine diagnostic delay and characterize the early and late diagnosis group. χ2 and Mann-Whitney tests were used, when appropriate, to investigate the evolution of time to diagnosis, and to identify factors associated with significant diagnostic delay. p < 0.05 was considered statistically significant. Analyses were carried out using SPSS Statistics®, version 29.
Results
A total of 285 patients were included. The mean diagnostic delay in this 17-year period was 10.1 ± 10.3 years, with a median of 6 years (0–45). There was no difference in time to diagnosis comparing the last 5 years (2018–2022) with the previous period (2006–2017), p = 0.454 (Table 1). Clinical and demographic characteristics of early and late diagnosis group are summarized in Table 2. A diagnostic delay of more than 5 years was significantly associated with an earlier onset of symptoms, with the location of HS on the breast or thighs, with a follicular phenotype, and also with the presence of cardiovascular (arterial hypertension and dyslipidemia) and psychiatric comorbidities (Table 2). In addition, smoking (active or previous) and body mass index ≥25 kg/m2 were also associated with a longer delay in diagnosis (Table 2). On the other hand, a personal history of acne and a greater disease severity (measured by IHS4) were associated with an earlier HS diagnosis (Table 2). Family history of HS and past medical history of pilonidal sinus were not associated with early or late HS diagnosis.
Table 1.
Evolution of time to diagnosis of HS (2006–2022)
| 2006–2017 | 2018–2022 | p value | |
|---|---|---|---|
| Time to diagnosis | 0.454 | ||
| Time to diagnosis (mean, SD), years | 9.9 (10.4) | 10.4 (10.3) | |
| Time to diagnosis (median, IQR), years | 5 (15) | 6 (15) | |
| Time to diagnosis (range), years | 0–40 | 0–45 |
SD, standard deviation; IQR, interquartile range.
Table 2.
Clinical and demographic characteristics of early and late diagnosis group
| Characteristics | Early diagnosis (≤5 years) | Late diagnosis (>5 years) | p value |
|---|---|---|---|
| Sex, n (%) | 0.506 | ||
| Male | 52 (36.6) | 47 (32.9) | |
| Female | 90 (63.4) | 96 (67.1) | |
| Race, n (%) | 0.225 | ||
| Caucasian | 125 (88) | 132 (92.3) | |
| Black | 17 (12) | 11 (7.7) | |
| Age at onset, median (IQR), year | 23 (20) | 18 (13) | 0.005 |
| Phenotype, n (%) | 0.013 | ||
| Follicular | 20 (14.1) | 37 (25.9) | |
| Inflammatory | 122 (85.9) | 106 (74.1) | |
| Smoking (active and previous), n (%) | 74 (54) | 119 (83.2) | <0.001 |
| Family history of HS, n (%) | 28 (19.7) | 40 (28) | 0.102 |
| BMI, n (%) | 0.019 | ||
| <25 kg/m2 | 66 (46.5) | 47 (32.9) | |
| ≥25 kg/m2 | 76 (53.5) | 96 (67.1) | |
| Comorbidities, n (%) | |||
| Arterial hypertension | 12 (8.5) | 30 (21.1) | 0.003 |
| Dyslipidemia | 16 (11.3) | 39 (27.3) | <0.001 |
| Diabetes Mellitus | 9 (6.4) | 16 (11.3) | 0.143 |
| Depression | 15 (10.6) | 29 (20.3) | 0.025 |
| Acne | 58 (40.8) | 41 (28.7) | 0.031 |
| Pilonidal sinus | 38 (26.8) | 50 (35) | 0.134 |
| Disease severity (IHS4), n (%) | 0.025 | ||
| Mild (<3) | 44 (31) | 64 (44.8) | |
| Moderate (4–10) | 59 (41.5) | 55 (38.4) | |
| Severe (≥11) | 39 (27.5) | 24 (16.8) | |
| Body areas affected, n (%) | |||
| Axillae | 91 (64.1) | 97 (67.8) | 0.504 |
| Groin | 95 (66.9) | 105 (73.4) | 0.229 |
| Perineum | 21 (14.8) | 14 (9.8) | 0.199 |
| Breast | 26 (37.7) | 43 (62.3) | 0.020 |
| Thighs | 14 (10.2) | 29 (20.3) | 0.020 |
| Gluteus | 36 (25.4) | 48 (33.6) | 0.128 |
| Face | 9 (6.3) | 6 (4.2) | 0.420 |
IQR, interquartile range; BMI, body mass index; IHS4, International Hidradenitis Suppurativa Severity Score System.
Discussion
In the last years, we have observed a growing interest of the medical-scientific community in HS. However, the diagnostic delay of 10.1 years in our population is aligned with previous studies from Germany, France, and worldwide: 10.0 ± 9.6 years in Kokolakis et al. [2], 8.4 ± 9.1 years in Loget et al. [3] and 7.2 ± 8.7 years in Saunte et al. [4]. Thus, our study not only confirms a significant diagnostic delay of HS in Portuguese patients but also highlights the lack of its improvement throughout these 17 years.
As described in previous studies [2, 3], the early onset of symptoms seems to be associated with a greater diagnostic delay, with the underdiagnosis of HS at a younger age being a possible explanation. Moreover, the distribution of the dermatosis on the breasts and thighs, as well as the follicular phenotype, was associated with a significant diagnostic delay. These data were not previously described and may be explained by a lack of awareness of these clinical HS phenotypes. In addition, smoking and overweight or obesity, two risk factors widely associated with the development of HS, were also associated with later diagnosis in our population. While the latter is aligned with previous studies [10], data regarding smoking and time to diagnosis appear controversial in literature [3, 4]. The association of these comorbidities with a later diagnosis may be explained by the delay of these patients in seeking medical care. In fact, smoking may be an inadequate coping strategy, and the wrong attribution of clinical manifestations of HS to being overweight or obese may also contribute to a later diagnosis.
This study further points out the potential consequences of HS diagnostic delay. In our population, the longer diagnostic delay was associated with a higher prevalence of cardiovascular and psychiatric comorbidities. Although the impact of a prolonged systemic inflammation on the development of cardiovascular comorbidities is established in the literature [2, 11], available studies have failed to demonstrate the association of a late diagnosis of HS with a higher prevalence of these comorbidities [2]. On the other hand, a recently published study showed that a prolonged course of the disease seems to be associated with a higher prevalence of depressive syndrome [2], prompted by the psychosocial impact of this chronic, potentially disfiguring, and debilitating disease.
Finally, past medical history of acne and a greater disease severity were associated with an earlier diagnosis of HS. The association of acne with an earlier diagnosis was not previously described in literature and the association with HS severity is controversial [2, 3]. However, these two associations may be attributed to an earlier referral of these patients to dermatology.
The self-reported nature of the clinical data, together with the small population and single-center retrospective nature of this study, is possible limitations. However, the lack of improvement in HS diagnostic delay, in opposition to the growing scientific interest in the disease, is clear. Our results reflect not only our local setting, but an apparently similar European reality that must be urgently inverted. In fact, there is still a major diagnostic delay in HS compared to other dermatological diseases like psoriasis, in which time to diagnosis is about 1.6 years [4]. Additionally, the association of a diagnostic delay with less typical phenotypes and with cardiovascular or psychiatric comorbidities is herein reinforced, as it is scarcely mentioned in literature. More importantly, these findings emphasize the need of an earlier diagnosis, in order to improve the healthcare provided to HS patients. It is, indeed, mandatory to increase public awareness on HS and to further educate health professionals, including other medical specialties, toward an earlier recognition of the disease.
Statement of Ethics
Written informed consent was obtained from all patients and their parents/legal guardians (patients under 18 years old) for participation in the study and publication of their case details. This study complied with the Declaration of Helsinki. This retrospective review of patient data did not require ethical approval in accordance with local guidelines.
Conflict of Interest Statement
The authors have no conflicts of interest to declare.
Funding Sources
The authors received no financial support for the authorship or publication of this article.
Author Contributions
Inês Aparício Martins and Beatriz Figueira Vilela: contributed to data collection, analysis and interpretation, and drafting of the manuscript.
Joana Cabete: contributed to data collection, data analysis and interpretation, and revision of the article.
Funding Statement
The authors received no financial support for the authorship or publication of this article.
Data Availability Statement
Data are not publicly available due to ethical reasons. Further inquiries can be directed to the corresponding author.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data are not publicly available due to ethical reasons. Further inquiries can be directed to the corresponding author.