Defining Fistular Patterns in Hidradenitis Suppurativa: Impact on the Management.

Background: Recent studies suggest that there are different fistular subtypes in hidradenitis suppurativa (HS) patients who are associated with variable therapeutic outcomes.
Objective: To describe clinical and ultrasound features that characterize the different fistular patterns in HS and to evaluate the response to medical therapies.
Methods: A retrospective study developed by a well-recognized center specialized in HS analyzing both clinical and ultrasound (US) aspects of fistular structures in HS patients was performed. Medical therapy response was evaluated through follow-up visits at Week 24.
Results: A total of 117 fistulas detected in the skin of 40 patients were evaluated. Four different types of fistulas were described: dermal fistula (Type A), dermoepidermal fistula (Type B), complex fistula (Type C), and subcutaneous fistula (Type D). Fistulas Type A and B showed a complete resolution after 6 months of different medical therapies in up to 95% and 65% of cases, respectively. Contrary to this, fistulas Type C and D showed no significant response after a medical intervention.
Conclusion: The US evaluation seems to play an important role to define these important structures that will help the clinician in elaborating a personalized combined medical and surgical management of the HS patient.