Summary We report eight cases of patients with severe acne who were treated with isotretinoin and developed painful nodules in the axillae and groin, consistent with hidradenitis suppurativa (HS). The pathogenesis of HS is still not completely understood; recent research from a study in 2011 of biopsies from HS lesions showed a reduction or absence of sebaceous glands compared with normal skin in patients with HS, with the report suggesting that this contributes to the pathogenesis of the disease. Interestingly, the main effect of isotretinoin is to decrease the size and action of sebaceous glands, so hypothetically, as isotretinoin acts by reducing the sebaceous glands further it could potentially aggravate HS. Our experience has instilled caution in our prescribing of isotretinoin, and we question patients, particularly those with acne conglobata, about symptoms of HS prior to and during treatment.

No abstract

Pyoderma gangrenosum (PG) is an autoinflammatory neutrophilic dermatosis characterized by rapidly enlarging, painful ulcers. Anakinra is a recombinant interleukin (IL)-1 receptor antagonist that blocks the activity of IL-1a and IL-1b by competitively inhibiting IL-1 binding to the IL-1 type 1 receptor. We present a series of two patients with recalcitrant PG, who had limited therapeutic options and multiple comorbidities and multiple previous treatment failures, who obtained 100% healing with anakinra. Compared with conventional first-line therapies for PG, the safety profile of anakinra may be preferable for patients with multiple comorbidities. Further research is needed to assess the safety and efficacy of anakinra for PG.

The authors would like to thank all patients and healthy volunteers for participating in this study and Andrew McGuigan and the surgical team in St. Michael's Hospital, Dublin. This study was partially funded by a UCD Newman Fellowship sponsored by Abbvie (JM). The authors thank Achilleas Floudas for helpful discussions.

No abstract