Could isotretinoin flare hidradenitis suppurativa? A case series.

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.