The search strategies were customized for each separate database by using various combinations of the keywords, such as "hidradenitis suppurativa," "acne inversa," "infliximab," and "adalimumab." In the PubMed/MEDLINE database, a Medical Subject Headings (MeSH) strategy of ("Hidradenitis Suppurativa"[MeSH] OR "Acne Inversa") AND ("adalimumab"[MeSH] OR "infliximab"[MeSH] OR "Tumor Necrosis Factor-alpha/antagonists and inhibitors"[MeSH]) was employed. Here, TNF is linked to hidradenitis suppurativa.