Initially there is severe throbbing pain at the anus + fever.
Later the pus bag (abscess) ruptures and pus comes out of the outer skin opening. The pain settles down. But as soon as the pressure of pus is relieved, the outer opening heals itself.
…………Now as the inner opening is patent and contamination gets lodged in it every time one passes stools thereby bringing fresh loads of bacteria which again start growing in the cavity of the tunnel.
Again there is severe pain -> rupture of abscess –>pus flows out –> relief of pain –> re-formation of abscess –> severe pain –> rupture –> pus flows –> relief –> re-abscess…………
(goes on & on with interval between two attack varying from few days to few months)
The pus can come out from a separate opening on the skin is further attacks and not necessarily from the same previous outer opening.
Later patient can notice that they pass gas from the outer opening / openings
Finally stools leak from the outer opening / openings.
