Janeway lesions
Janeway lesions are non-tender, small erythematous or haemorrhagic macular or nodular lesions on the palms or soles only a few millimeters in diameter that are pathognomonic of infective endocarditis. Pathologically, the lesion is described to be a microabscess of the dermis with marked necrosis and inflammatory infiltrate not involving the epidermis, which is due to the deposition of circulating immune complexes in small blood vessels.

# Overview
- Janeway lesions are irregular, flat, painless, erythematous macules found on the palms, soles, thenar and hypothenar eminences of the fingertips, hands and plantar surfaces of the toes.
Stigmata of infectious endocarditis
Considered a criterion (albeit minor) of vascular phenomena
- Stigmata of infectious endocarditis
- Considered a criterion (albeit minor) of vascular phenomena

# Etymology
They are named after Edward G. Janeway (18411911), a professor of medicine with interests in cardiology and infectious disease.

# Diagnosis
(Images courtesy of Charlie Goldberg, M.D., UCSD School of Medicine and VA Medical Center, San Diego, CA)
- Janeway Lesions: Flat, painless, erythematous lesions seen on the palm of this patient's hand. Frequently associated with bacterial endocarditis.
- Janeway Lesion: Flat, painless, erythematous lesions seen on the palm of this patient's hand. While frequently associated with bacterial endocarditis, in this case, they are the result of an infected radial artery aneurysm (inflamed area proximal to thumb).
- Janeway Lesions: Flat, painless, erythematous lesions seen on the palm of this patient's hand. Frequently associated with bacterial endocarditis.
- Janeway Lesions: Flat, painless, erythematous lesions seen on the palm of this patient's hand. Frequently associated with bacterial endocarditis.

## History and Symptoms
- IV drug abuse
- Infective endocarditis
- Structural heart disease
- Heart valve injury/replacement
- Family history of autoimmune disorders
- HIV status
- Mucosal bleeding
- Head/neck or lung infection
- Tick exposure
- Constitutional symptoms

## Laboratory Findings
- Blood cultures
- Complete blood count (CBC) with peripheral smear
- Antinuclear antibody (ANA)
- Rapid plasma reagin (RPR)
- Erythrocyte sedimentation rate (ESR)
- Antistreptolysin O antibodies (ASO)
- Urinalysis
- Coagulation studies
- Anti-SM antibodies
- Anti-dsDNA antbodies

## Chest X Ray
- Chest X-ray

## Echocardiography or Ultrasound
- Echocardiogram

## Other Diagnostic Studies
- Possible biopsy

# Differential Diagnosis
In alphabetical order.  
- Acute bacterial endocarditis
- Coxsackievirus
- Cutaneous vasculitis
- Disseminated Intravascular Coagulation (DIC)
- Echovirus
- Erythema multiforme
- Idiopathic thrombocytopenia purpura
- Meningococcemia
- Polyarteritis Nodosa
- Rocky Mountain Spotted Fever
- Secondary syphilis
- Subacute bacterial endocarditis
- Systemic Lupus Erythematosus
- Thrombotic thrombocytopenic purpura
- Typhoid Fever

## Acute Pharmacotherapies
- IV antibiotics
- Antibiotic prophylaxis
- Treat all underlying etiologies

## Chronic Pharmacotherapies
- Antibiotic therapy for bacterial endocarditis

# Surgery and Device Based Therapy
- Valve replacement for bacterial endocarditis

## Indications for Surgery
- If all other medical therapy fails (bacterial endocarditis)