Overview
A sty (hordeolum) is a painful red lump on or inside the eyelid, caused by infection of an eyelid gland or hair follicle — usually by Staphylococcus aureus bacteria. External sties form along the lash line; internal sties are deeper in the eyelid. Most sties resolve on their own within 1 to 2 weeks. A chalazion is a non-infectious blocked meibomian gland that may look similar.
How common is it?
Styes are common eyelid problems. Blepharitis can make them more likely; many settle without specific medical treatment.
Causes and risk factors
Bacterial infection, usually Staphylococcus aureus, blocks and infects the glands in the eyelid.
Common risk factors
- Touching or rubbing eyes with unwashed hands
- Sharing eye cosmetics or contact lens equipment
- Blepharitis (chronic eyelid inflammation)
- Skin conditions: acne rosacea, seborrhoeic dermatitis
- Contact lens use
- Previous sty (risk of recurrence)
Symptoms
- Painful red swelling on the edge of the eyelid
- Visible yellow pus-filled centre as it develops
- Swelling and redness of the surrounding eyelid
- Watering eye
- Discomfort when blinking
- Feeling of a foreign body in the eye
When to see a doctor
Seek urgent assessment for a very painful or swollen stye, affected vision, pus from the eye, spreading redness or fever. See a GP if it is not improving after a few weeks. Do not wait for that interval if symptoms are worsening.
Diagnosis
Clinical diagnosis by examination. No investigations required in uncomplicated cases.
Treatments
Warm compresses
The primary treatment. Apply a warm, clean cloth to the closed eyelid for 10 to 15 minutes, 3 to 4 times daily. Heat promotes blood flow and softens the blocked gland, encouraging spontaneous drainage. This resolves most sties within 1 to 2 weeks.
Antibiotics only when clinically indicated
Most uncomplicated styes do not need antibiotics. A clinician may prescribe them for associated infection or spreading eyelid cellulitis; do not self-start eye antibiotics.
Incision and drainage
For sties that do not resolve after 2 to 3 weeks or are particularly large and painful, incision and drainage under local anaesthetic provides rapid relief.
Self-care and lifestyle
- Never squeeze or pop a sty — this can spread the infection
- Remove eye make-up completely each evening and replace eye cosmetics every 3 to 6 months
- Do not wear contact lenses until the sty has healed
- Do not share towels, washcloths, or eye cosmetics
Prevention
Wash hands before touching the eye area. Remove all eye make-up before sleeping. Treat blepharitis promptly with lid hygiene measures. Do not share eye cosmetics.
Sources for targeted updates
Updated: 24 October 2026. Targeted corrections to urgent-care guidance, treatment, key facts, frequency. This update covers the named sections; a full review of the remaining guide is pending.