Epidermis to endocardium: mapping the association between atopic dermatitis and infective endocarditis.

Infective endocarditis (IE) is a rare, life-threatening infection of the cardiac endocardium caused by bacterial seeding. On the other hand, atopic dermatitis (AD) is a common inflammatory skin condition that disrupts the epidermal barrier, increasing susceptibility to Staphylococcus aureus colonisation and recurrent bacteraemia. This provides a biologically plausible bridge to IE, which we explore in this current literature review. MEDLINE, Embase and CENTRAL were searched from inception to 7 April 2025. Sixteen studies were included - 15 case reports and one retrospective cohort study - which were grouped into three categories: well-controlled AD with no predisposing risk factors, AD with predisposing risk factors, and uncontrolled AD or alternative AD management. This review is made up of 24 patients with IE secondary to AD. Of the 16 studies, nine originated from Japan. Mean age was 29.6 years (range 15-42 years), which is significantly younger than classic IE cohorts (mean 60.0 years). Staph. aureus accounted for 23/24 patients, and the mitral valve was affected in 18/24 cases. In terms of patient outcomes, all but one patient survived, but valve surgery was necessary in 20/24 patients. In conclusion, AD-related IE shows a distinct pattern: younger patients, Staph. aureus dominance and mitral valve involvement requiring mitral valve surgery in the majority. This potential link appears to be under-recognised, hence, greater cross-speciality awareness and rigorous AD control for those at high risk is recommended. The heavy Japanese skew in the literature highlights the need for broader case documentation in other regions to confirm this link across different patient demographics.