BACKGROUND: Chronic non-healing or recurrent inflammatory lesions, reminiscent of infection but recalcitrant to antibiotic therapy generally characterize biofilm driven-diseases. Chronic lesions of Hidradenitis Suppurativa (HS) exhibit several aspects, which are compatible with well-known biofilm infections.

OBJECTIVE: To determine and quantify the potential presence of bacterial aggregates in chronic HS lesions.

METHODS: In 42 consecutive HS patients suffering from chronic lesions, biopsies were obtained from lesional as well as from perilesional skin. Samples were investigated using Peptide Nucleic Acid (PNA) - Fluorescence in situ Hybridization (FISH) in combination with Confocal Laser Scanning Microscopy (CLSM). In addition, corresponding histopathological analysis in hematoxylin and eosin slides were performed.

RESULTS: Biofilms were seen in 67% of the samples of chronic lesions and in 75% of the perilesional samples. The mean diameter of aggregates in lesional skin was significantly greater than in perilesional skin (p=0.01). Biofilms exceeding 50 μm in diameter were found in 42% of lesional samples and only in only 5% of the perilesional samples (p=0.009). The majority of the large biofilms (aggregates > 50 μm in diameter) were situated in sinus tracts (63%) or in the infundibulum (37%). The majority of the sinus tract samples (73%) contained active bacterial cells, which were associated with inflammation.

CONCLUSION: This study suggests that biofilm is associated with inflammation of chronic HS lesions. The aggregates most likely occur as a secondary event, possibly due to predisposing local anatomical changes such as sinus tracts (tunnels), keratinous detritus and dilated hair follicles. This article is protected by copyright. All rights reserved.