Hidradenitis suppurativa/acne inversa: a prospective bacteriological study of 46 patients and review of the literature

BACKGROUND: Hidradenitis suppurativa is a chronic inflammatory disease of the hair follicle that usually involves specific anatomic areas which are partially occluded, have a higher density of eccrine and apocrine sweat glands and a higher pH. These characteristics could promote the superinfection of certain group of bacteria. We aimed to describe the bacteria that can be isolated from hidradenitis lesions and to establish a correlation between bacteriological results and clinical data. METHODS: We prospectively enrolled forty-six patients presenting purulent or seropurulent discharge. Sixty samples were performed using swabs, which were deeply introduced in the lesions. RESULTS: Fifty-two percent of cultures resulted positive and fifteen bacterial species were isolated. The more prevalent species were Proteus mirabilis and Staphylococcus aureus. Samples from advanced cases were more likely to yield a positive bacterial growth. CONCLUSIONS: In our study the rate of positive cultures increased in more severe stages of the disease, thus bacterial superinfection of established lesions may contribute to maintain chronic inflammation. We could not find statistically significant correlation with the sampled anatomic area or specific group of bacteria. Larger prospective studies should be performed.