Infectious Risks Associated with Biologic Therapies in Autoimmune, Rheumatologic and Dermatologic Diseases: A Narrative Review

Biologic and targeted synthetic therapies have substantially improved the management of autoimmune diseases (ADs), achieving unprecedented disease control. However, by modulating key immune pathways, these agents increase susceptibility to a wide spectrum of infections. This narrative review synthesizes current evidence on infectious risks associated with biologic DMARDs (bDMARDs) and targeted synthetic DMARDs (tsDMARDs) in AD, characterizing infection profiles across different drug classes, identifying patient- and treatment-related risk factors, and providing evidence-based recommendations for screening, prevention, and management. A comprehensive literature search was conducted through March 2026, across PubMed, Embase, and the Cochrane Library, using predefined search terms combining biologic and targeted synthetic drug classes with infection-related outcomes. Evidence from major international registries (BSRBR-RA, DANBIO, RABBIT) and society guidelines (ACR, EULAR, IDSA) was prioritized. Among bDMARDs, TNF-α inhibitors (TNF-α i) and rituximab were associated with the highest rates of serious infections, whereas IL-17 and IL-23 inhibitors demonstrated comparatively lower infectious risk profiles. Steroids, older age, and prior serious infections emerged as the most consistent patient-related risk modifiers. Unlike prior reviews focused on single diseases or drug classes, this work provides an integrated, cross-disciplinary risk stratification framework. bDMARDs and tsDMARDs remain among the most innovative treatments available for effective management of ADs, with favorable benefit–risk profiles when accompanied by systematic prevention strategies. Universal pre-treatment screening for tuberculosis and viral hepatitis, risk-stratified parasitic screening, evidence-based vaccination, and selective antimicrobial prophylaxis can mitigate infectious complications.