Hi! thanks for writing to us! Well, formation of pus indicates kind of recent infection and necrosis of tissue; therefore, if were your family physician and had you consulted me for the recurrent pus formation in the armpit area, I would just think of a few possibilities like: 1. a ruptured and infected epidermal cyst 2. tuberculous infection 3. hidradenitis suppurativa-like infection of skin adnexae 4. inflamed fibrocystic disease in ectopic mammary tissue as in females! Therefore you need some microbiological/cytopathological testing for confirmation and thereafter the line of treatment could easily be decided by your surgeon! Please revert back to us if necessary. wishing you early recovery!