The diagnosis is suspected with a history of recurrent angioedema. It is confirmed by finding abnormally low levels of C1 esterase inhibitor in the blood. The cause, Rochalimaea quintana, is an unusual rickettsia that multiplies in the gut of the body louse. Onset of symptoms is sudden, with high fever, headache, back and leg pain and a fleeting rash. Recovery takes a month or more.
Relapses are common.
Quintan means recurring every 5 days and refers to the fever. Also called five-day fever. Recurring each day, as in a fever that returns every day. From the Latin quotidianus for daily. The result of mathematical division.