Ultrasound Detection of Retained Hair Tracts in Hidradenitis Suppurativa

The study assessed the presence and size of ectopic hair tract fragments in patients with Hidradenitis Suppurativa (HS) using ultrasound imaging. Out of 50 consecutive HS patients (32 women and 18 men with a mean age of 31 years), 40 patients (80%) showed ectopic hair tract fragments within fluid collections and/or fistulae in the dermis and hypodermis. These fragments tended to run parallel to the skin layers, which is abnormal compared to their usual perpendicular orientation. The mean length of hair tracts was 4.4 mm, with a range of 2-31.7 mm. The study concluded that the high presence of ectopic hair tract fragments supports their pathogenic role in HS, as they may act as foreign bodies, maintaining the inflammatory reaction and potentially worsening the disease. The study suggests that these findings could be relevant to the pathophysiology and severity of HS. Further research, including immunologic studies and detailed protein chemistry, is needed to understand the effects of these hair fragments on the clinical management of HS.