Osler nodes

Osler nodes are painful, small, erythematous or violaceous nodules typically found on the pulp of the fingers and toes (and occasionally on the thenar/hypothenar eminences). Pathophysiology is thought to involve immune complex deposition (type III hypersensitivity reaction) leading to a localized vasculitis, distinguishing them from Janeway lesions, which are painless, macular, erythematous lesions on the palms and soles caused by septic microemboli from valve vegetations. Osler nodes are considered a minor Duke criterion for the diagnosis of infective endocarditis (IE) and are relatively uncommon, seen more often in subacute bacterial endocarditis. Mnemonic: 'Osler's nodes are Ouchy (painful)' while 'Janeway lesions are Just there (painless).' Other findings associated with IE include Roth spots (retinal hemorrhages with pale centers), splinter hemorrhages (linear reddish-brown streaks under the nails), and splenomegaly. Clinically, when Osler nodes are found, infective endocarditis should be strongly suspected, and blood cultures and echocardiography should be pursued. They can occasionally be seen in other conditions such as systemic lupus erythematosus, disseminated gonococcal infection, and marantic (nonbacterial thrombotic) endocarditis, but classically are tested in the context of subacute bacterial endocarditis, often caused by organisms like Streptococcus viridans.