**3. Epidemiology**

HS is a disease with few epidemiological data described in the literature, with a large part of North American and European studies. It was considered a rare condition, mainly due to diagnostic errors and underreporting existing cases [5, 7]. In young European population, its prevalence is around 1–4% globally [8, 9]. In the United States, a study in Minnesota estimated a prevalence value of 0.13%, which is lower than that presented in Europe [10]. Regarding the age group, the disease is common between puberty and 40 years of age, being more frequent between 21 and 29 years of age, tending to decrease and disappear in women after menopause [5, 7]. The occurrence in females is higher, with a ratio of three females to one male. Perineal and perianal disease is more prevalent in males and is also more severe and associated with an increased risk of degeneration to squamous cell carcinoma [7, 11]. A Dutch study shows that disease severity is closely linked to disease, body mass index, male gender, and smoking [12]. There is evidence that the higher the body mass index, the greater the severity of the disease. HS was 10 times more prevalent in the morbidly obese compared to the general population [12, 13]. The relationship between smoking and HS was related in 60–70% of patients, but not associated with disease severity. There is no pattern of racial or even ethnic predilection today [13, 14].
