Recent findings suggest that an imbalance in gut microbiota (dysbiosis), could play a significant role in the progression of inflammatory skin disease, Hidradenitis Suppurativa (HS). HS is a painful, long-term skin condition, with a chronic and relapsing nature that significantly impacts patients’ quality of life. Researchers at Hacettepe University in Turkey collected faecal samples from 15 patients with HS and 15 age- and sex-matched healthy individuals and analysed regions of the bacterial 16S rRNA gene to investigate differences in their gut microbiota. Researchers found that the relative abundance of three genera of bacteria (known collectively as Firmicutes), unclassified Clostridiales, unclassified Firmicutes and Fusicatenibacter in HS patients were significantly lower than that in controls (p = 0.005, p = 0.029, and p = 0.046, respectively).

Reduced amounts of these bacteria are known to disrupt the regulatory balance within the gut and stimulate an inflammatory response. Studies have increasingly demonstrated that the gut microbiome and skin are intrinsically connected, offering defence against pathogens in the environment. This relationship is known as the ‘gut-skin axis’ and has been linked to many inflammatory and autoimmune skin disorders, such as acne and psoriasis. This connection inspired the researchers to characterise the composition of HS patients’ intestinal microbiome, hypothesising that imbalance may play a role in the high inflammatory burden of this condition.

HS is a multifactorial disease caused by both genetic and environmental factors. Obesity and smoking can significantly exacerbate symptoms, and both of these have an impact on the gut microbiome. Dr Neslihan Demirel Ogut, Usak University Training and Research Hospital, Turkey, explained:

“Our research provides evidence that the gut-skin axis is implicated in the progression of this chronic inflammatory skin disorder. While further evidence is required, our research suggests that dietary alteration and personalised probiotic supplementation might also be beneficial for HS patients, particularly since treatment options are limited for these individuals.” 

Gut microbiota play a critical role in human health through development of the immune response, controlled by specific pathways and the products of metabolism, known as short-chain fatty acids (SCFA). Bacteria in the gut (such as Firmicutes) produce these SCFAs that ensure a balance between immune cells that stimulate or suppress an inflammatory response is maintained. Any disruption to this balance, as demonstrated by the reduced abundance of these organisms in the gut microbiome of HS patients, may induce an unwanted inflammatory response. The findings were presented at the European Association of Dermatology and Venereology 2021 Spring Symposium.