Understanding Hidradenitis Suppurativa: Pathophysiology and Staging

Announcer:
You’re listening to Clinician’s Roundtable on ReachMD. On this episode, we’ll hear about the clinical presentation of hidradenitis suppurativa, or HS, from Dr. Daniel Klufas, who is an Assistant Professor of Dermatology at the University of California, San Francisco. Let’s hear from Dr. Klufas now.

Dr. Klufas:
HS is a complex chronic skin disease. It’s usually characterized by painful inflammatory nodules or abscesses as well as dermal tunnels, tracts, and fistulae, and it has a predilection for the intertriginous skin, meaning areas like the groin, armpits, and under the breast. It predominates in females and disproportionately affects African Americans. Interestingly, it also has a bimodal distribution of disease onset, so you see this early peak in the late teen years and then a later onset, usually in the fifth decade of life. It carries a substantial disease burden due to its prevalence, associated comorbidities, and quality of life impacts, and it’s also associated with some higher healthcare resource utilizations. Now, it differs from other skin conditions like psoriasis or atopic dermatitis because much less is known about the actual molecular pathways involved in the inflammatory cascade. So because of this, we’re limited with our treatment options for targeted therapies, and we have less in our arsenal to actually treat the disease.

When you think about typical symptoms and stages of HS, it’s important to understand a little bit more about the pathophysiology of the disease. So HS is commonly mistaken as an infectious disease, but it’s actually a complicated inflammatory disorder of the hair follicle. And this is accompanied by immune dysregulation, some underlying genetic factors, and dysbiosis—meaning alterations in the skin microbiome—which can all trigger a pretty robust immune response. So the primary trigger in HS is thought to be plugging or dilation of the hair follicle, and this ultimately leads to rupture of the follicle and then inflammation of the surrounding glands and structures. Over time, this will lead to abscess and sinus tract formation.

And then when you think about the progression of the disease, HS has three stages and is classified by the Hurley staging system. So Hurley stage I presents as isolated abscesses or inflammatory nodules without any sinus tracts or scarring. Stage II has recurrent abscesses with sinus tracts and evidence of scarring. And then stage III, which is the most severe, presents with numerous interconnected tracts or abscesses, usually involving an entire anatomic region.

Announcer:
That was Dr. Daniel Klufas talking about hidradenitis suppurativa. To access this and other episodes in our series, visit Clinician’s Roundtable on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!