The role of imaging technologies in the diagnosis of hidradenitis suppurativa.

Hidradenitis suppurativa is a chronic, inflammatory, recurrent, and debilitating disease of the hair follicle. It presents with painful, deep-seated, inflamed lesions, such as nodules, abscesses, sinus tracts, and fistulas, generally located in the main folds. Clinical severity assessment alone can be reductive; noninvasive skin imaging technologies, such as ultrasound, magnetic resonance imaging, medical infrared thermography, computed tomography, and positron emission tomography, provide subclinical anatomical and functional details. These instrumental techniques confirm the clinical suspect, thus allowing an earlier diagnosis and improving patients' clinical evaluation, staging, and management. Finally, they might be helpful for preoperative mapping. In this contribution, we provide an overview of the current knowledge about noninvasive skin imaging techniques with a particular focus on ultrasonography, which is widely used thanks to its precision, versatility, and availability.