BACKGROUND: Patients with hidradenitis suppurativa (HS) often report opportunistic infections such as herpes and urinary tract infections.

AIM: To compare opportunistic infections in patients with HS against a group of healthy controls (HCs).

METHODS: In total, 99 patients with HS and 109 HCs were recruited at random to this retrospective case-control study. We devised a questionnaire to explore the frequency of minor infections, general practitioner (GP) visits and sick days experienced during the past 6 months. Additionally, participants were asked if they felt unwell more often compared with their peers.

RESULTS: Patients with HS felt unwell more often than did HCs (26.3% vs. 7.3%, P < 0.001). Although there was no difference between the groups in five of the seven diseases studied, patients with HS had a higher frequency of the common cold (P < 0.01) and genital herpes (P < 0.01). Number of pack-years of smoking did not affect risk of infections (Pearson correlation, P = 0.51). Subgroup analysis of nonsmokers found the same differences in frequency of minor infections, common cold and genital herpes between patients with HS and controls.

CONCLUSIONS: Patients with HS appear to experience more frequently symptoms compatible with minor infections in general, and the common cold and genital herpes specifically. This results in more GP visits and more sick days. Further research is needed to determine if this is caused by an immunological hyper-reactive state in these patients or a reduced threshold for minor infections.