Background: Hidradenitis suppurativa (HS) is an overlooked but common disease severely affecting both genders. HS is generally perceived as difficult to treat and although a number of treatments are available, the need for more effective treatment is apparent. Objectives: Cyclosporine A (CsA) has been suggested as an effective treatment in four smaller case series. It was therefore decided to review a larger series of cases, reporting all outcomes in order to provide a less biased base for evaluating the potential of CsA for use in HS. Methods: An exploratory retrospective review of case notes was performed at three departments of dermatology with a special interest in HS, where HS had been treated with CsA in the period 2009-2012. Results: In total, 18 HS patients treated with CsA were identified and analysed and 50% reported some benefit. All patients had previously been treated with multiple various other modalities. Limitations: This is an exploratory retrospective review with a limited number of patients. Conclusions: This retrospective review found some effect of CsA in the recalcitrant cases studied, mainly reported as "slight improvement". This may be due to a number of factors which may have overestimated (e.g. concommitant therapy) or underestimated (e.g. case selection of recalcitrant cases) the effect, and indicates the need for prospective evaluation of the claims. The present data provide a basis for power calculations in future studies investigating the potential for treating HS with CsA in a randomised controlled trial.