boils

Boil, also known as furuncle, is a localized skin infection that originated in a hair follicle or oil gland. It presents as a painful, swollen nodule that becomes firm, reddened, and warm, often with a central pus-filled area. Boils are most commonly caused by Staphylococcus aureus; they can occur anywhere but are common on the neck, face, armpits, buttocks, and thighs. When several boils coalesce or occur in one area, the condition may form a carbuncle, a larger inflamed mass.

Risk factors include skin trauma, friction, poor hygiene, diabetes, immune suppression, and colonization with S. aureus. Boils may arise after minor folliculitis; bacteria enter through hair follicles, triggering inflammation and pus accumulation.

Diagnosis is usually clinical based on appearance. In some cases, drainage fluid can be cultured to guide treatment, and imaging is reserved for suspected deeper infection.

Management begins with measures to promote drainage and prevent spread. Small boils often drain on their own after several days; warm compresses and good local wound care are recommended. Incision and drainage by a clinician may be necessary for larger boils or those that do not drain spontaneously. Antibiotics are not always required; they are used when there is surrounding cellulitis, fever, numerous boils, immunocompromise, or infection near the eyes or other critical areas. When antibiotics are used, options target Staphylococcus aureus and may vary based on local resistance patterns.

Complications such as cellulitis, abscess formation, scarring, or recurrent boils can occur. Preventive measures include good personal hygiene, avoiding sharing personal items, proper wound care, and addressing predisposing conditions.

Most boils heal with drainage within 1–3 weeks, though recurrence is common in some individuals.