The infection of the anal gland, in the perianal area is the main cause for
" Peri-Anal Abscess". This Peri-Anal Abscess burst open discharging pus leaving an external opening which refuses to heal but persists to cause" Fistula in Ano". This external opening once formed heals with medical treatment, only to recur' usually at the same site, after an interval of few weeks to few months.