Comment on 'The effects of isotretinoin therapy on serum homocysteine, folate and vitamin B12 levels in patients with acne': may retinoids be useful to treat hyperhomocysteinemia found in patients affected by hidradenitis suppurativa?. (19th November 2019) - Marasca, C.; Donnarumma, M.; Annunziata, M.C.; Fabbrocini, G.