Addictions in Hidradenitis Suppurativa: A Cross-Sectional Pilot Study

Abstract

Introduction

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a significant impact on a patient’s daily life, negatively affecting numerous psychological and physical aspects. Thus, patients with HS may be at elevated risk of developing addictive disorders. We therefore aimed to evaluate the prevalence of the most common addictions and psychiatric comorbidities among patients with HS.

Methods

This questionnaire-based pilot study was conducted between January and October 2021 at the Department of Dermatology and Allergology, School of Medicine and Health, Technical University of Munich, Germany. Demographics, disease severity, quality of life, presence of depression and anxiety, addictions including smoking habits, alcohol consumption, consumption of illicit drugs and prescription drugs, cannabis consumption, gambling, internet and food addiction were recorded.

Results

A total of 120 patients (48.3% female, 51.7% male; mean age 39.3 ± 13.2 years) with HS were included. Most patients suffered from mild HS. Screening results for at least one addiction were positive in 71.7% of the participants, while smoking was most prevalent (60.0%), followed by pathological alcohol consumption (18.3%), food addiction (18.3%) and cannabis addiction (15.0%). Moreover, positive screening rates were 13.3% for addiction to illicit drugs or prescription medication, 12.5% for internet addiction and 5% for gambling. Using multivariate logistic regression, the correlation of patients’ characteristics with addictive disorders was determined. Younger patients were more susceptible to internet, cannabis and food addiction. Food addiction was more prevalent in patients with an increased BMI. Addiction to illicit drugs or prescription medication was associated with anxiety.

Conclusion

Strikingly, numerous addictions were recorded in patients with HS, even in those with mild disease severity. Thus, addictions in patients with HS should be addressed in time by physicians to provide early patient-centred health care.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-026-01744-8.

Plain Language Summary

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with an immense impact on a patient’s daily life. Patients are negatively affected in numerous psychological and physical aspects. Thus, patients with HS may be at elevated risk of developing addictive disorders. We therefore aimed to evaluate the prevalence of the most common addictions and psychiatric comorbidities among patients with hidradenitis suppurativa. Thus, we conducted a questionnaire-based study between January and October 2021 at the Department of Dermatology and Allergology, School of Medicine and Health, Technical University of Munich, Germany. We recorded patients’ demographics, disease severity, quality of life, presence of depression and anxiety, addictions including smoking habits, alcohol consumption, consumption of illicit drugs and prescription drugs, cannabis consumption, gambling, internet and food addiction. A total of 120 patients participated in this study. Most patients suffered from mild HS. Nearly three-quarters of the participants had a positive screening for at least one addiction. More than half of the patients smoked, and nearly one-fifth consumed alcohol in a pathological manner or showed signs of food addiction. Younger patients were more susceptible to internet, cannabis and food addiction. An increased body mass index was associated with food addiction. Furthermore, anxiety was also associated with addiction to illicit drugs or prescription medication. Taken together, patients suffering from hidradenitis suppurativa show numerous positive screenings for addictions even when disease severity was mild. Physicians should address this issue in time to provide early patient-centred health care.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-026-01744-8.

Key Summary Points

Why carry out this study?

Patients suffering from hidradenitis suppurativa (HS) are prone to develop mental distress and social exclusion, which are known to be driving forces to develop addictive disorders.

Determination of the prevalence of common addictions, mental disorders and risk factors will improve care of patients with HS.

What was learned from the study?

Patients with HS show a high prevalence of the seven most common addictions and numerous patients present with two or more addictions.

Strikingly, the presence of addictions was shown to be independent of HS severity.

Comprehensive clinical care of patients with HS has to consider addiction as a relevant comorbidity requiring early intervention and interprofessional patient care.

Introduction

Hidradenitis suppurativa (HS), also termed acne inversa, is a chronic skin disease which manifests as recurrent deep inflamed lesions such as nodules, abscesses, fistulas and scarring in areas with apocrine glands [1]. Usually, HS develops after puberty. Often being misdiagnosed or underdiagnosed, the prevalence of HS is challenging to determine. Estimated prevalence ranges from under 1% to as high as 4%, with more female individuals being affected [2]. Unfortunately, patients often suffer from diagnostic and therapeutic delay of up to 10 years [3]. Associations with numerous autoimmune and autoinflammatory diseases imply that HS is not only a sole skin disease but also a systemic disease with underlying systemic inflammation [4]. Moreover, patients suffering from HS are more likely to be obese; smoking habits also show a correlation with disease severity [5].

The last decade saw tremendous progress in understanding disease pathogenesis and identification of putative therapeutical targets [1, 6]. Consequently, numerous treatment options can be offered now to patients with HS, including topical therapy, systemic therapy with antibiotics and inhibition of tumour necrosis factor alpha (TNFα) and interleukin (IL)-17, respectively. Surgery remains the mainstay in treating extensive tunnel formation and tissue destruction [7]. Despite the advances made so far, treatment often remains challenging [8, 9].

Chronic pain, social exclusion and permanent and persistent disability in patients with HS occur along with not only physical but also psychological distress, and can be driving forces towards addiction and substance abuse [10]. Previous studies evaluating other chronic inflammatory skin diseases and addiction showed that smoking habits and alcohol dependency were more common in patients with psoriasis compared to the general population [11]. In addition, alcohol use disorder seems to be more frequent in patients with atopic dermatitis (AD) [12, 13]. Data on addiction and its association with dermatological diseases are generally rare [10, 14]. Therefore, this explorative pilot study aims to evaluate the occurrence of addictions in patients with HS along with psychiatric diseases, including depression and anxiety.

Methods

Study Design and Participants

This non-interventional, cross-sectional, exploratory pilot study was conducted from January to October 2021 at the Department of Dermatology and Allergology, School of Medicine and Health, Technical University of Munich. Patients attending the HS outpatient clinic received a paper-based survey and were included consecutively. Inclusion criteria were a confirmed HS diagnosis and the ability to answer the German questionnaire. Moreover, participants had to be aged ≥ 18 years, and written informed consent was required. The study was reviewed and approved by the Ethics Committee of the Faculty of Medicine at the Technical University of Munich (646/20 S-KH) and was performed in accordance with the Helsinki Declaration of 1964, and its later amendments. All patients gave informed consent to participate in the study and for recording and analysing their given information.

Physical Examination and Personal Data

Disease severity was assessed by dermatologists by using the Hurley stage and IHS4 [15]. Furthermore, the following items were documented: age, sex, weight, height, pain (numeric rating scale (NRS) from 1 to 10), previous surgeries due to HS and the current systemic therapy.

Questionnaire

Validated and internationally recognised screening instruments were used for the assessment of addictions and substance abuse. Details can be found in Supplementary Table 1.

The CAGE questionnaire consists of four questions regarding individual alcohol consumption [16, 17]. For evaluation of smoking, patients should state the number of cigarettes consumed per day and also for how long they have been smoking to calculate pack years. Cannabis addiction was evaluated by the Cannabis Abuse Screening Test (CAST) with a cut-off value of five considered as cannabis dependency [18]. To provide a quick index of drug abuse problems, the Drug Abuse Screening Test (DAST-10) was used [19, 20]. Gamblers Anonymous 20 questions (GA-20) was used to detect pathological gambling [21, 22]. Pathologic behaviour regarding internet use was quantified by the Compulsive Internet Use Scale (CIUS) [23]. Possible food addiction was evaluated using the modified Yale food addiction scale 2.0 (mYFAS 2.0) [24]. In addition, screening for depression was assessed by the WHO-5 Well-Being Index (WHO-5) and the presence of anxiety disorders was detected by using Generalised Anxiety Disorder 7 (GAD-7). To assess disease-related impairment regarding quality of life, the Dermatology Life Quality Index (DLQI) was also performed. Moreover, patients were asked to rate their overall happiness.

Statistical Analysis

Descriptive data were generated using mean and standard deviation (mean ± SD) as well as absolute numbers and proportions. Results for prevalence estimation and further analyses were defined by thresholds listed above. Data were stratified by gender and age. Group differences were examined using an unpaired t test and the chi-squared test. To identify personal and clinical factors (age, sex, BMI, DLQI, IHS4, pain scale 0–10, WHO-5, GAD-7, overall happiness) associated with the occurrence of one of the seven addictions, logistic regression models were calculated. The factors listed above were added to multivariate logistic regression models, and adjusted odds ratios (aOR) were calculated with their respective 95% intervals (95% CI) to determine their association with the outcome of addiction screenings performed. Global alpha was set at 0.05. Data was analysed using IBM SPSS Statistics (version 27, IBM Corporation, Armonk, NY, USA).

Results

Patients Characteristics

A total of 120 patients participated in this study. The mean age was 39.3 ± 13.2 years; 58 (48.3%) were male and 62 (51.7%) were female. The mean BMI was 29.6 ± 6.1 kg/m². Thus, 35 (29.2%) patients were overweight with a BMI greater than 25 kg/m² and 52 (45.3%) were obese with a BMI greater than 30 kg/m² according to the WHO definition. Seventy-eight (65.0%) participants had Hurley stage I, 25 (20.8%) suffered from Hurley stage II, and 15 (12.5%) presented Hurley stage III. According to IHS4, 60 (50%) had mild (1–3 points), 40 (33.3%) moderate (4–10 points), and 14 (11.7%) had severe HS (≥ 10 points). Most patients did not receive systemic therapy at consultation (63.3%), but around half (52.5%) had had surgery before.

Quality of Life, Rating of Happiness and Pain

The mean DLQI was 10.6 ± 7.5. Thirty-four (28.3%) patients reported a moderate impact of HS on their lives, whereas 51 (42.5%) reported HS to have a large or extremely large effect on their quality of life. Median overall happiness was rated at 5.8, with no significant difference between men (6.5) and women (5.7). Fifty-one patients (42.5%) reported no pain (0/10) at the consultation, 31 patients (25.8%) reported little pain (1–3/10) and 20 patients (21.7%) suffered from moderate to severe pain (4–10/10). Mean overall pain was rated 2.2, with no significant differences between men (2.1) and women (2.2). Twelve patients (10%) did not rate their current pain (Table 1). The severity of pain due to HS showed a highly significant correlation with the quality of life (r = 0.469; p < 0.001).

Table 1.

Patients’ characteristics

	Total n = 120	Men n = 58	Women n = 62	p value
Age, mean (± SD)	39.3 (13.24)	40.4 (13.2)	38.3 (13.3)	0.386
BMI, mean (± SD)	29.5 (6.1)	29.69 (6.1)	29.4 (6.2)	0.789
Hurley stage, n (%)
Stage I	78 (65.0%)	33 (56.9%)	45 (72.6%)	0.027*
Stage II	25 (20.8%)	13 (22.4%)	12 (19.4%)
Stage III	15 (12.5%)	12 (20.7%)	3 (4.8%)
IHS4, mean (± SD)	4.8 (4.9)	5.8 (5.8)	3.8 (3.7)	0.071
DLQI, mean (± SD)	10.6 (7.5)	9.5 (7.2)	11.8 (7.7)	0.898
Pain, mean (± SD)	2.2 (2.6)	2.1 (2.8)	2.2 (2.6)	0.881
Happiness, mean (± SD)	5.8 (2.4)	6.5 (2.3)	5.7 (2.5)	0.893
Depression, n (%)
Screened positive	38 (31.7%)	15 (25.9%)	23 (37.1%)	0.147
Screened negative	80 (66.7%)	43 (74.1%)	37 (59.7%)
Missing	2 (1.7%)	0	2 (3.2%)
Anxiety, n (%)
No	44 (36.7%)	25 (43.1%)	19 (30.6%)	0.018*
Mild	42 (35.0%)	24 (41.4%)	18 (29.0%)
Moderate	27 (22.5%)	6 (10.3%)	21 (33.9%)
Severe	7 (5.8%)	3 (5.2%)	4 (6.5%)
Missing	0	0	0

Differences between genders were compared using an unpaired t test for continuous variables and a chi-square test for ordinal and nominal scaled variables

SD standard deviation, BMI body mass index, DLQI Dermatology Life Quality Index, IHS4 International Hidradenitis Suppurativa Severity Score System

*Significant results

Prevalence of Depression and Anxiety

Thirty-eight (31.7%) patients screened positive for depression. Twenty-seven (22.5%) had moderate levels of anxiety, and 7 (5.8%) had severe levels of anxiety. Women more often screened positive for both depression (37.1% vs. 25.9%) and anxiety (69.4% vs. 56.9%) than men. Moreover, women had significantly higher scores regarding anxiety measured by GAD-7 than men (p = 0.018) (Table 1).

Prevalences of Addictive Behaviour

Overall, 72 (60.0%) patients reported smoking, of which 59 (49.1%) smoked daily, with a mean pack years (py) of 27.3 py, and 6.7% smoked occasionally. For 6.7%, data were missing (Fig. 1a). Overall 22 (18.3%) participants screened positive for pathological alcohol consumption, with men being affected significantly more often than women (32.8% vs. 4.8%, p < 0.001) (Fig. 1b). Men were also more likely to screen positive focption (aOR 10.12, 95% CI 1.77–57.88) (Table 2).

Fig. 1.

Prevalence of positive screenings for addictive disorders. Values in percentages. Prevalence in women, green; prevalence in men, orange; overall prevalence, blue

Table 2.

Factors associated with addictive behaviour

	Age	Male gender	BMI	IHS4	DLQI	Pain	Happiness	GAD7	WHO5
Smoking	1.03 (0.99–1.07)	0.57 (0.21–1.57)	0.95 (0.87–1.03)	0.95 (0.85–1.05)	0.97 (0.89–1.05)	1.14 (0.92–1.43)	0.87 (0.63–1.18)	0.98 (0.85–1.14)	1.01 (0.94–1.07)
Alcohol	1.01 (0.97–1.05)	10.12 (1.77–57.88)	1.00 (0.90–1.12)	1.08 (0.96–1.20)	0.93 (0.83–1.03)	0.85 (0.64–1.13)	0.88 (0.59–1.31)	1.14 (0.93–1.40)	1.04 (0.94–1.16)
Illicit drugs/medications	0.94 (0.88–1.00)	5.01 (0.84–29.74)	1.05 (0.91–1.21)	1.12 (0.96–1.29)	0.93 (0.83–1.05)	0.97 (0.73–1.29)	0.89 (0.57–1.39)	1.31 (1.03–1.66)	1.09 (0.96–1.23)
Cannabis	0.94 (0.89–0.99)	0.40 (0.09–1.61)	0.98 (0.87–1.10)	1.08 (0.93–1.25)	0.99 (0.89–1.09)	0.98 (0.77–1.24)	0.68 (0.45–1.03)	1.07 (0.89–1.28)	0.95 (0.84–1.07)
Gambling	0.93 (0.85–1.04)	8.3 (0.40–173.85)	1.05 (0.82–1.34)	0.95 (0.76–1.21)	1.03 (0.85–1.24)	0.98 (0.62–1.53)	0.89 (0.44–1.83)	1.21 (0.82–1.80)	1.07 (0.87–1.31)
Food	0.93 (0.88–0.99)	2.80 (0.62–12.68)	1.24 (1.08–1.42)	0.96 (0.82–1.12)	0.99 (0.89–1.12)	1.15 (0.88–1.51)	1.24 (0.80–1.91)	1.22 (0.99–1.48)	0.94 (0.84–1.06)
Internet	0.90 (0.84–0.98)	1.91 (0.38–9.69)	1.09 (0.94–1.27)	0.91 (0.76–1.09)	0.98 (0.85–1.09)	1.29 (0.95–1.75)	1.04 (0.63–1.73)	1.12 (0.88–1.40)	0.97 (0.87–1.12)
More than one positive screening for addictive behaviour	0.98 (0.95–1.02)	2.39 (0.82–6.97)	1.03 (0.94–1.12)	2.05 (0.97–4.37)	0.94 (0.86–1.03)	0.97 (0.78–1.2)	0.95 (0.71–1.28)	1.16 (0.99–1.354)	1.01 (0.92–1.10)
Positive screening for addictive behaviour with the exception of smoking	0.98 (0.94–1.01)	2.67 (0.95–7.45)	1.08 (0.99–1.17)	1.72 (0.79–3.69)	0.93 (0.85–1.01)	0.98 (0.79–1.21)	0.94 (0.71–1.25)	1.17 (1.01–1.37)	0.99 (0.87–1.14)

Results of binary logistic regression models calculated to assess dependent variables (age, male gender, BMI, IHS4, DLQI, pain, overall happiness, GAD-7, WHO-5) for the positive screening for addictive behaviours evaluated in this study

BMI body mass index, DLQI Dermatology Life Quality Index, IHS4 International Hidradenitis Suppurativa Severity Score System, GAD-7 Generalised Anxiety Disorder 7, WHO-5 WHO-5 Well-Being Index

Twenty-seven (22.5%) patients reported at least mild problems with drug addictive behaviour defined using DAST-10. Sixteen (13.3%) patients exceeded the threshold for addictive behaviour to illicit drugs or prescription medication (Fig. 1c). Positive screening results for addictive behaviour to illicit drugs and prescription medication were associated with higher scores in GAD-7 anxiety screening (aOR 1.31, 95% CI 1.03–1.66) (Table 2).

When cannabis consumption by was evaluated with CAST, 25 (20.8%) patients reported cannabis consumption in the past 12 months (Fig. 1d); 18 (15.0%) showed signs of addictive behaviour to cannabis (Fig. 1e). Also here, younger age was associated with the occurrence of addictive behaviour to cannabis (aOR 0.94, 95% CI 0.89–0.99) (Table 2).

GA-20 showed positive screening for pathological gambling behaviour in 6 (5.0%, 4 male, 2 female) patients (Fig. 1f). Positive screening rates did not differ significantly between men and women.

Concerning internet addiction, 15 (12.5%) patients showed pathological behaviour (Fig. 1g). Younger patients were more likely to suffer from internet addiction (aOR 0.90, 95% CI 0.84–0.98) (Table 2).

Twenty-two (18.3%) patients screened positive for food addiction (Fig. 1h). Of these, 14 (11.7%) had mild, 2 (1.7%) moderate and 6 (5.0%) severe forms of addictive food intake. Positive screening for food addiction was significantly associated with younger age (aOR 0.93, 95% CI 0.88–0.99) and higher BMI (aOR 1.24, 95% CI 1.08–1.42) (Table 2).

Summarising the results, 71.7% of all patients (43 men, 43 women) screened positive for at least one addictive disorder, including smoking (Fig. 2a, b). Forty-seven (39.2%, 29 men, 18 women) screened positive for at least one addictive behaviour besides smoking (Fig. 2c, d). Thirty-seven (30.8%, 23 men, 14 women) patients reported having more than one positive screening for an addiction (Fig. 2e, f). Men were more likely to display addictive behaviour besides smoking (50.0% vs. 29.0%, p = 0.015) and to report two or more addictions (39.7% vs. 22.6%, p = 0.036) (Fig. 2d, f).

Fig. 2.

Screening for addictive disorders. Positive screening for at least one addictive disorder in a the overall study population and b stratified by men and women. Positive screening for at least one addictive disorder with the exception of smoking in c the overall study population and d stratified by men and women. Positive screening for two or more addictive disorders in e the overall study population and f stratified by men and women. Values in percentages. Positive screening, blue; negative screening, grey; positive screening in men, orange; positive screening in women, green

Addictive Behaviour-Associated Factors

Using multivariate logistic regression, we aimed to determine the correlation of patients’ characteristics with a positive screening of an addictive behaviour. Objective disease severity correlated with subjective burden of disease evaluated by DLQI (r = 0.203; p = 0.3 (objective disease severity rated by Hurley stage); r = 0.283; p = 0.03 (objective disease severity rated by IHS4)). Interestingly, high DLQI had no influence on addiction. Male gender was a significant factor favouring pathological alcohol consumption (aOR 10.12, 95% CI 1.77–57.88). Younger age was associated with the occurrence of addictive behaviour to cannabis (aOR 0.94, 95% CI 0.89–0.99), food addiction (aOR 0.93, 95% CI 0.88–0.99) and internet addiction (aOR 0.90, 95% CI 0.84–0.98) (Fig. 3, Table 2). Moreover, higher levels of anxiety were associated with illicit drugs and prescription medication dependence (aOR 1.31, 95% CI 1.03–1.66) and with the presence of an addictive behaviour, except smoking (aOR 1.17, 95% CI 1.01–1.37 (Fig. 3, Table 2). Also, a higher BMI indicated a higher chance of food addiction (aOR 1.24, 95% CI 1.08–1.42) (Fig. 3, Table 2).

Fig. 3.

Significant association of clinical and personal factors with positive screenings for addictive behaviour as revealed by binary logistic regression. BMI body mass index, GAD-7 Generalised Anxiety Disorder 7

Discussion

This study aimed to determine the prevalence of numerous substance and behavioural addictions along with depression and anxiety disorders in patients with HS and to detect associated clinical parameters.

Most of the patients in this study suffered from mild to moderate HS, but even mild disease can have a similar impact on quality of life compared to those presenting with moderate or severe disease [25]. Most of our patients were moderately impaired by HS with a mean DLQI of 10.6 ± 7.5.

Mental health disorders such as depression, anxiety and adjustment disorders are increased in patients with HS [26]. In our cohort, both anxiety and depression were highly prevalent, with nearly every third patient affected compared to a reported prevalence of 8.1% for current depressive symptoms and a lifetime prevalence for depression of 11.6% in the general German population [27]. Interestingly, we found that patients with HS and anxiety were more prone to screen positive for drug addiction, in contrast to previously published data, where substance use disorders, including opioids, cannabis and alcohol consumption, had the highest association in patients without depression and anxiety [10]. This discrepancy may arise from the fact that the latter study used a different data source (health care records).

Concerning problematic alcohol consumption, 18.3% of the patients with HS screened positive. A recent cross-sectional study using electronic health records data in the USA showed a significantly higher prevalence of alcohol dependence in patients with HS (4.2%) compared with matched controls (0.52%) [28]. Looking at the general population in Germany, 5.9–8.1% are considered to display problematic alcohol consumption [29]; therefore, international comparisons regarding alcohol consumption appear to be problematic. Nevertheless, there is a known association between inflammatory skin diseases and heavy alcohol consumption [12]. Recent studies demonstrated that 12.1% of patients with AD and 13.5% of patients with psoriasis display alcohol use disorders [13, 30]. The prevalence of smoking has been reported to be highly increased in patients with HS, ranging from 17.9% up to 88.9% [4]. While 60% of patients with HS in our study stated to be smokers, 28.3% of the German population are assumed to be smokers [31]. Regular smoking is more frequent in patients with psoriasis, with 34.6% and 15.0% of AD patients stated to be smokers [32]. Thus both pathological alcohol consumption and smoking are more prevalent in patients with HS compared to patients with psoriasis, AD and the general population.

Regarding internet addiction and gambling, 12.5% and 5.0% screened positive, respectively. As these are considered to be more novel addictions, this study seems to be the first to have investigated their context in HS. Patients with AD showed a 4.5% positive rate for internet addiction and a 3.2% rate for gambling [13]. In the general population, internet addiction and pathological gambling are rare, with an approximate rate of 1.0–2.1% and 1%, respectively [23, 33, 34]. In contrast, 19.0% of patients with psoriasis have been identified to be compulsive gamblers [30]. Therefore, it can be assumed that patients with HS feature behavioural addictions such as internet addiction and gambling more frequently than the German population. Compared to other chronic inflammatory diseases, patients with HS are more likely to show compulsive gambling than patients with AD, but less frequently compared to patients with psoriasis.

Another relatively novel field of addiction, which has not been sufficiently investigated in regard to HS, is food addiction. In our study, 18.3% of the patients screened positive using the mYFAS 2.0. Although no data regarding HS is available so far, the association of overweight or obesity with HS could be considered an indirect indicator of inadequate food intake [35]. In Germany, nearly 8% of the general population met the criteria of food addiction [36]. Again, patients with HS suffer from food addiction more frequently than the general population. Thus, it is not surprising that a correlation between BMI and food addiction has been observed in this study, as a known correlation between food addiction and obesity exists [37]. Obesity might also contribute to HS pathogenesis not only through subclinical inflammation but also through increased friction in the skin folds [6]. Therefore targeting obesity by using lifestyle modification, such as enhanced physical activity and dietary modifications, is of utmost importance to break the inflammatory vicious circle present in HS [38]. Glucagon-like peptide 1 (GLP-1) agonists may also play an increasing role in controlling body weight, metabolic syndrome and inflammation in HS [39]. Interestingly, food addiction in patients with psoriasis displays a lower prevalence (3.1%), which is even below that of the general population [30]. Drucker et al. studied the association of atopic conditions, including AD, with food addiction in US women and found that 9.7% of patients with AD featured food addiction compared to 8.2% of the control group [40].

Substance-related disorders in general, including abuse and/or dependence on cannabis, amphetamines, cocaine and hypnotics/sedatives, are estimated to affect 3% of the general German population [29]. Overall 22.5% of the patients in our study reported at least a low level of problems with drug addiction, and 13.3% screened positive for substance abuse, which is higher than in the general population. Patients with HS also showed a higher prevalence compared to patients with psoriasis and patients with AD with 10.6% and 12% positive screening rates for substance-related disorders, respectively [32]. A recently published study evaluating cannabis use in France demonstrated that patients with HS had a significantly greater prevalence of cannabis use (34%) compared to patients with psoriasis (11.6%) and the general population (11%) [14]. This is in line with our results; 20.8% of our patients reported cannabis use in the past 12 months, and 15.0% even showed signs of cannabis addiction. The Epidemiological Survey of Substance Abuse (ESA) reported a prevalence of cannabis use of 9.8% and cannabis dependence of 1% in the German population [41]. A study conducted in the USA showed that the prevalence of substance abuse in general was significantly higher among patients with HS compared to the general population. Alcohol abuse constituted almost 50% of all substance abuse cases evaluated, followed by opioids (32.7%) and cannabis (29.7%). Patients with HS had 1.5 times the adjusted odds of substance abuse disorder compared to those without HS [10]. The high prevalence of opioid addiction might be due to regional problems in the USA and the opioid crisis, with 2% regularly using opioids and an additional 2.9% using opioids less frequently [42].

When investigating the prevalence of addictions, healthcare records are often used. In contrast, the design of our study using primary health data provides the unique opportunity to assess co-occurrences of addictions, too. Thus, 71.7% of the patients with HS screened positive for one addiction—with the majority reporting nicotine abuse (60%)—and 30.8% for more than one addiction. Moreover, using multivariate logistic regression analysis risk factors such as younger age or male gender could be determined for several addictions, paving the way for further stratified investigations.

This study has several limitations. As this was a questionnaire-based study, false declarations due to pudency when answering the questions cannot be excluded, and the instruments yield positive screening prevalence rather than true prevalence, which may differ from the pathological classification. Furthermore, a corresponding control group with a similar questionnaire is lacking to draw a more consolidated conclusion. Besides, selection bias cannot be excluded when considering the generalizability of the findings, as answers were collected in the HS outpatient clinic, where presumably mainly patients who are highly negatively affected in their quality of life—irrespective of their objective disease course, compared to the general HS population—might seek help. In addition, the majority of patients with HS in this investigation suffered from mild disease; thus, findings in patients with severe HS may be different. In regard to the reported associations in the multivariate analysis it has to be stated that in items with only few positive screenings the study is not sufficiently powered and these associations may be unstable. Finally, the wide confidence intervals have to be attributed to the explorative nature of the study and the corresponding sample size.

Conclusion

This exploratory pilot study clearly demonstrates that the prevalence for a positive screening of the seven common addictive disorders is high in patients with HS. Indirect comparison to other studies shows increased rates compared to the general population and also to patients with other chronic inflammatory diseases, such as atopic eczema or psoriasis. Especially younger and male patients are more likely to be affected by several addictions. Strikingly, patients with mild HS are as prone to develop addictions as patients with moderate or severe disease. Therefore, it is of utmost importance that physicians focus on these patients who might be currently overlooked. Regarding the complexity of addiction with plenty of possible contributing factors such as mental disorders, social imprinting, chronic pain and chronic diseases with accompanying substantial impairment of life quality, it is essential for physicians to be aware of possible addictions in patients with HS and also to address them in order to improve patient care.

Supplementary Information

Below is the link to the electronic supplementary material.

Author Contributions

Alexander Böhner, Alexander Zink and Thomas Volz initiated and designed the project. Wanja Steinhauser and Rosi Wang, with help of Alexander Böhner and Thomas Volz, collected the data. Wanja Steinhauser, Alexander Böhner, Christian Posch, Tilo Biedermann and Thomas Volz analysed and interpreted the data. Alexander Böhner, Rosi Wang and Wanja Steinhauser wrote the paper with input from all authors. Christian Posch, Tilo Biedermann, Alexander Zink and Thomas Volz critically revised the manuscript. All authors finally approved the version to be published.

Funding

No funding or sponsorship was received for this study or publication of this article. The Rapid Service Fee was funded by the authors.

Data Availability

The datasets generated and analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Conflict of Interest

Alexander Böhner received honoraria from AbbVie for presentations. Christian Posch received honoraria and travel support from AbbVie, BMS, Pelpharma, LEO Pharma, SUN Pharma, Sanofi, MSD, Almirall, Pfizer, Pierre Fabre, Eli Lilly, Janssen, a grant from Almirall and consulting fees from Novartis, all unrelated to this project. Alexander Zink has been an advisor and/or received speaker’s honoraria from AbbVie, Novartis, UCB, unrelated to this project. Tilo Biedermann received grants from Almirall, Celgene-BMS, Lilly, Novartis, Sanofi-Genzyme, Regeneron and Viatris, received travel support from Almirall, Alk-Abello, Sanofi-Genzyme, received consulting fees from AbbVie, Alk-Abello, Almirall, Boehringer Ingelheim, Leo Pharma, Lilly, Novartis, Sanofi-Genzyme and Viatris, received honoraria from Alk-Abello, Almirall, GSK, Leo Pharma, Lilly, Novartis, Sanofi-Genzyme, Regeneron, and is a member of the advisory board of Alk-Abello, Almirall, Boehringer Ingelheim, Leo Pharma, Lilly, Novartis, Sanofi-Genzyme and Viatris. Thomas Volz received grants from AbbVie and Novartis, received consulting fees and honoraria from Novartis and UCB Pharma. Wanja Steinhauser and Rosi Wang have no conflict of interest to declare.

Ethical Approval

The study was reviewed and approved by the Ethics Committee of the Faculty of Medicine at the Technical University of Munich (646/20 S-KH) and was performed in accordance with the Helsinki Declaration of 1964, and its later amendments. All patients gave informed consent to participate in the study and for recording and analysing their given information.