CONFLICT OF INTEREST: None declared.

TLDR: A rare case of hidradenitis suppurativa (HS), diagnosed by definition criteria, with multiple subcutaneous abscesses with spontaneous drainage of pus, sub cutaneousindurations and scars in bilateral inguinal areas, which had appeared 10 years prior and rapidly increased in number.

Abstract: lated (to a maximum of 40 mg/day) or tapered according toUC activity. She was taking 5 mg/day at the initial visit to us.Physical examination showed multiple subcutaneousabscesses with spontaneous drainage of pus, subcutaneousindurations and scars in bilateral inguinal areas (Fig. 1a), butneither axillae nor buttocks were involved. Bacterial culturesyielded Streptococcus anginosus. Histological examinationshowed increase of collagenous fibers and infiltration of inflam-matory cells such as lymphocytes and neutrophils in the deepdermis (Fig. 1b), containing a number of CD3-, 4- and interleu-kin (IL)-17-positive cells (Fig. 1c). She was treated with oral anti-biotics (minocycline 200 mg/day). Additionally, she hadbrownish dermal nodules scattered on her trunk and legs(Fig. 1d), which had appeared 10 years prior and rapidlyincreased in number. Physical examination revealed seven nod-ules in total, but she denied familial occurrence. Histology ofthose nodules showed an ill-defined proliferation of fibrohistio-cytic cells in the dermis, containing foamy histiocytes (Fig. 1e).Toluidine blue stain revealed a number of mast cells in theperipheral layers of the fibrotic lesions (Fig. 1f), correspondingto the IL-17-positive cells on serially cut sections (Fig. 1g).We herein described a rare case of hidradenitis suppurativa(HS), diagnosed by definition criteria,