---
title: What causes a stye?
description: "A stye, or hordeolum, is a tender lump at the eyelid margin caused by acute infection of an eyelash follicle or associated gland. It often appears as a red, painful swelling. ## How It Develops Bacteria from the skin, commonly…"
url: "https://bluefinvision.com/knowledge-base/topics/symptoms-signs/what-causes-a-stye/"
updated: "2025-12-12"
category: "Symptoms & Signs"
---

# What causes a stye?

A stye, or hordeolum, is a tender lump at the eyelid margin caused by acute infection of an eyelash follicle or associated gland. It often appears as a red, painful swelling.

## How It Develops

Bacteria from the skin, commonly Staphylococcus species, infect a blocked gland or follicle. Risk factors include blepharitis, poor lid hygiene, contact lens or make‑up contamination, and rubbing the eyes with unclean hands.

- External styes point towards the lash line, while internal ones involve deeper meibomian glands
- Swelling, local tenderness, and a small yellow head may be seen
- Recurrent styes can evolve into firm, non‑tender chalazia
- Underlying skin conditions like rosacea may predispose to frequent episodes

## Implications

Most styes settle with warm compresses and lid hygiene but some require medical treatment or drainage. Persistent or atypical lumps need evaluation to exclude other lid lesions.

- Antibiotic ointment or tablets are sometimes prescribed for significant infection
- Do not squeeze or pierce a stye yourself
- Seek assessment if the whole lid becomes very swollen or vision is affected
- Regular lid care can reduce recurrence in blepharitis‑related cases