Hello, Boils (furuncles) are painful pus-filled bumps on the skin resulting from the deep infection of a hair follicle. The infection is usually caused by a type of bacteria called Staphylococcus aureus ( staph ). Untreated boils can enlarge or grow together to form a giant multi-headed boil (carbuncle). Boils may resolve with simple self-care measures, but the infected fluid (pus) needs to drain in order for them to heal completely. Many boils drain of their own accord, or they can be lanced by a health care professional. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr K. V. Anand, Psychologist