Many HS patients mention previous surgery for supposed pilonidal sinus, with a tendency to recur several times. Clinically it is very difficult to be sure that these "pilonidal sinuses" are not in fact localized HS. It is particularly difficult to distinguish the two if histopathology has not been performed and if the patient keeps having abscesses in the gluteal cleft. The differential diagnosis is further complicated by the fact that pilonidal sinus is most often treated by surgeons, whereas HS is treated by dermatologists; and the diagnostic criteria and specification may therefore differ by tradition and training.
The clinical picture is identical to a flare of HS, except for the strict localization to the glu-teal cleft [10, 34]. Histologically the identification of a substantial accumulation of terminal hair characterizes the pilonidal sinus. In contrast, terminal hair is not very frequently observed in of HS lesions, and when it occurs it usually just shows only as small fragments. Histology is however not regularly done on these lesions, and it is therefore not easy to find an estimate of the true frequency of the possible association between HS and pilonidal sinus. In addition to the histological differences and topographical limitations, the solitary nature of pilonidal sinuses also contrasts with the multi-focal nature of HS.
Mechanical strain has been implied as part of the pathogenesis of both diseases, but no conclusive experimental evidence has been presented yet.
Was this article helpful?