Doxycycline STI prophylaxis and the skin: a systematic review and meta-analysis of cutaneous adverse drug reactions and skin-relevant bacterial resistance

Systematic review and meta-analysis assessing (1) the proportion of people using doxycycline post-exposure or pre-exposure prophylaxis for bacterial sexually transmitted infections who develop cutaneous adverse drug reactions (including fixed drug eruption and photosensitivity), and (2) the association of doxycycline prophylaxis with colonisation by tetracycline- or doxycycline-resistant skin-relevant bacteria (Staphylococcus aureus, group A Streptococcus, coagulase-negative staphylococci, Cutibacterium acnes). Sources: PubMed, Europe PMC and ClinicalTrials.gov (searched 3 November 2026) plus citation searching. Eligible designs: randomised trials, observational studies, case series and case reports. Proportions are pooled with a random-effects generalised linear mixed model; ratio measures are presented by study design. Risk of bias is assessed with RoB 2 and Joanna Briggs Institute tools, and certainty with GRADE. Reporting follows PRISMA 2020 and PRISMA Harms. Note: this registration is retrospective; the protocol was drafted on 3 November 2026, after the searches and before full-text data extraction.