The use of ultrasonography (US) is becoming increasingly common in supporting diagnosis and treatment of hidradenitis suppurativa (HS). The main goal of this study was to correlate clinical evaluation with US findings, identifying markers that could predict a positive or negative response to adalimumab therapy. Disease duration was the most relevant clinical variable affecting disease severity and treatment response, highlighting the importance of both a timely diagnosis and a prompt therapy. Additionally, the subcutaneous involvement of HS lesions detected by US was associated with significantly lower response to therapy, constituting one negative predictive factor to adalimumab response.