<s>[INST] a friend of mine has had several episodes of severe infection of the coccyx.  he said the cause was because of hair growing on the coccyx turning inward and causing it to become infected.  He has lately had another bad infection causing a huge boil.  he went to the doctor again and had it lanced and packed. He was given antibiotics.  I am concerned about his condition. How can this be treated to prevent it from happening again..How can the hair be removed? [/INST] HiWelcome to HCM.I appreciate your concern for your friend.Apparently your friend is suffering from recurrent pilonidal sinus infection.Ingrown hair on the coccyx area (pilonidal sinus) needs to be excised and removed completely to prevent its recurrence. If it is not removed completely then a tract is formed and that gets infected again.A course of antibiotics is just sufficient to control the infection, however the incompletely removed tract or sinus should be excised thoroughly to prevent the recurrent infection.He should consult an expert surgeon to properly assess the length of the tract and to be removed completely with histopathological evidence.Hope this answers your query.A feed back is appreciated. </s>