Which antibiotic is best to treat hidradenitis suppurativa? should i get a culture? there can't be surgery due to severe haemophilia.

Hydradenitis: There is currently no known cure nor any consistently effective treatment. Antibiotics may be effective when there is secondary bacterial infection. See a good dermatologist and have a lengthy discussion about your options. Good luck and best wishes.

Based on cultures: Though some physicians will try a course of vancomycin, clindamycin, amoxicillin, and others, the best thing to do is to obtain cultures and sensitivities. Keep in mind the non-antibiotic-based therapies may be an option including the use of anti-TNF alpha therapy.