 Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum . The signs and symptoms of syphilis vary depending in which of the four stages it presents ( primary , secondary , latent , and tertiary ) . The primary stage classically presents with a single chancre ( a firm , painless , non @-@ itchy skin ulceration ) but there may be multiple sores . In secondary syphilis a diffuse rash which frequently involves the palms of the hands and soles of the feet occurs . There may also be sores in the mouth or vagina . In latent syphilis there are little to no symptoms which can last for years . In tertiary syphilis there are gummas ( soft non @-@ cancerous growths ) , neurological , or heart symptoms . Syphilis has been known as " the great imitator " as it may cause symptoms similar to many other diseases . 
