Key candidate genes involved in psoriasis pathogenesis and linked to the IL‐17A pathway were markedly overexpressed in HS lesional skin compared to non‐lesional and healthy skin, including DEFB4A, LCN2, S100A7A, CXCL8, and CXCL5 (all Figure 2B). This evidence concerns the gene DEFB4A and histiocytic sarcoma.