Trigger factors in systemic lupus erythematosus and atopic dermatitis: differences and similarities

Systemic lupus erythematosus (SLE) and atopic dermatitis (AD) share complex pathogenic mechanisms influenced by environmental, genetic, microbial, and metabolic factors. This narrative review summarizes recent evidence on these shared and distinct triggers, highlighting overlapping inflammatory pathways and points of mechanistic divergence between the two diseases, and considers the implications for cross-disease that may influence future therapeutic treatment. Shared triggers—Ultraviolet (UV) radiation, smoking, psychological stress, gut and cutaneous dysbiosis, nutrient imbalance, and microbial exposures ( Staphylococcus aureus ( S. aureus ), EBV/ Herpes Simplex Virus (HSV)—appear to converge on partially overlapping molecular pathways in both diseases (oxidative stress, NF-κB activation, NLR family pyrin domain-containing 3 (NLRP3) inflammasome, IL-1/IL-6/TNF-α background tone). These shared upstream signals may contribute to divergent immunopathology alarmin driven Th2/type 2 innate lymphoid cell (ILC2) inflammation and barrier failure in AD (“outside-in”) versus type I interferon-driven autoantibody production and immune-complex injury in SLE (“inside-out”)—because host genetics channel the response toward either barrier-permissive or nucleic-acid-driven effector arms. JAK/STAT activation appears to be an important shared molecular node across both diseases and underlies the observed cross-disease activity of JAK inhibitors. Mapping these interconnected triggers underscores opportunities for cross-disease interventions targeting cytokine signaling, immune balance, and microbiome restoration. Understanding these overlaps may provide valuable insights to develop integrated management strategies for autoimmune and inflammatory skin disorders.