Styes & Chalazia

A stye (hordeolum) is a red, swollen, tender bump on the eyelid caused by an acute bacterial infection of a small oil gland. A chalazion is a firm, usually painless lump in the eyelid caused by a blocked oil gland and a buildup of thickened oil that triggers chronic inflammation. Although these two conditions look similar and are often confused with each other, they have different causes and may need different treatments. Both involve the eyelid’s oil-producing glands—primarily the meibomian glands, which run in a row inside each eyelid and produce the oily outer layer of the tear film, and the smaller Zeis glands at the base of the eyelashes.

Both conditions are very common and almost always benign. A chalazion is one of the most frequently seen inflammatory eyelid conditions in eye care practice, affecting people of all ages. Most styes and chalazia resolve on their own or with simple home care. Neither condition is contagious. In rare cases, particularly when a stye spreads or a chalazion is atypical or keeps coming back, medical or surgical treatment is needed.

Both conditions are further divided based on which gland is affected and where in the eyelid the lesion forms.

• External stye (external hordeolum): an infection of the Zeis or Moll glands at the base of the eyelashes, along the outer edge of the lid. It appears as a small, painful pustule (pus-filled bump) directly at or near the lash line.
• Internal stye (internal hordeolum): an infection of a meibomian gland deeper inside the eyelid, within the firm internal plate of the lid (the tarsus). It produces a larger, deeper swelling that is often more painful than an external stye. A yellowish area may be visible on the inner surface of the eyelid when the lid is flipped.
• Deep chalazion (meibomian chalazion): a chronic, noninfected blockage of a meibomian gland that causes a firm, round nodule deep within the lid. It is usually felt as a painless pea-sized lump and is the most common type.
• Superficial chalazion: a similar blocked-gland nodule arising from the smaller Zeis glands near the lid margin, sitting closer to the skin surface than the deep type.
• Recurrent chalazion: a chalazion that keeps coming back, either in the same spot or at different locations on the eyelid. Recurrence is often a sign of an underlying condition such as blepharitis, meibomian gland dysfunction, or rosacea. Any chalazion that recurs in exactly the same location in an older adult should be biopsied to rule out a rare but serious condition called sebaceous gland carcinoma.

A stye is caused by an acute bacterial infection—most commonly by Staphylococcus aureus bacteria—that invades the oil glands of the eyelid and causes a localized abscess (pocket of pus). The infection triggers redness, swelling, and pain. A chalazion develops differently: it begins when the duct of a meibomian gland becomes blocked, trapping oil inside the gland. The retained oil gradually breaks down and triggers a chronic inflammatory reaction. Unlike a stye, a chalazion is not an active infection—it is a sterile (noninfected) inflammatory nodule. However, an untreated stye can sometimes evolve into a chalazion over time, as the acute infection resolves but the gland remains blocked and inflamed.

Several factors can make a person more prone to developing either condition. Chronic eyelid inflammation from blepharitis (lid margin disease) and meibomian gland dysfunction are the strongest predisposing factors, as they create the conditions for both bacterial overgrowth and gland blockage. Rosacea, seborrheic dermatitis, dry eye disease, allergies, and Demodex mite infestation of the eyelid follicles all contribute to the same cycle of gland dysfunction and inflammation that underlies both styes and chalazia.

The following factors increase the likelihood of developing a stye or chalazion:

• Blepharitis: Chronic eyelid margin inflammation is the single strongest risk factor for a chalazion. Bacteria and debris on the lid margin contribute to gland blockage and repeated infections.
• Meibomian gland dysfunction (MGD): Blocked or poorly functioning oil glands are the direct cause of most chalazia.
• Rosacea and seborrheic dermatitis: These inflammatory skin conditions frequently affect the eyelid margins and significantly raise the risk of both conditions.
• Dry eye disease: A disrupted tear film alters the composition of the oil in the meibomian glands, promoting blockage.
• Allergies: Allergic eye disease and atopic dermatitis are associated with higher rates of chalazia.
• Demodex mite infestation: Microscopic mites living in eyelash follicles and meibomian glands can obstruct gland openings and worsen inflammation.
• Poor eyelid hygiene: Allowing bacteria, mites, and debris to accumulate on the eyelid margins increases risk.
• Prior history: Having had a stye or chalazion before raises the likelihood of recurrence, especially without addressing underlying lid margin disease.

Neither styes nor chalazia require formal screening. Both are identified when a patient notices a lump or discomfort and seeks care, or when a doctor spots an eyelid abnormality during a routine examination. Neither condition can be fully prevented, but consistent eyelid hygiene and management of contributing conditions—particularly blepharitis, rosacea, and dry eye—significantly reduce how often they occur and how severe they become. Practical preventative steps include applying warm compresses daily to keep the meibomian glands flowing freely, cleaning the eyelid margins regularly with a gentle eyelid scrub or warm water, treating underlying rosacea or seborrheic dermatitis, avoiding rubbing the eyes, and maintaining proper contact lens hygiene if lenses are worn.

A stye typically appears suddenly, with pain and tenderness developing over hours. A chalazion usually grows more slowly, over days to weeks, and is noticed more as a bump than as a painful lesion.

Signs and symptoms include:

• A tender, red lump at or near the lid margin (stye): The bump is painful to touch, warm, and may develop a visible pus point at its tip as it comes to a head. It is most noticeable along the lash line.
• A firm, painless nodule in the eyelid (chalazion): feels like a smooth, round, movable pea under the skin of the lid. It is usually not tender unless it becomes secondarily infected or inflamed.
• Eyelid swelling and redness: The entire lid may appear puffy, particularly with an internal stye or a large chalazion.
  Tearing, gritty sensation, or mild light sensitivity: These are caused by associated blepharitis or conjunctival irritation from the lesion rubbing against the eye surface.
• Blurred vision: A large upper-eyelid chalazion can press on the cornea and induce astigmatism (an uneven corneal curve), causing mild visual distortion. This resolves when the chalazion is treated.
• Red-flag symptoms requiring urgent evaluation: Increasing pain, fever, rapid spread of swelling to the entire eyelid or face, restricted eye movement, or vision changes may indicate the infection has spread beyond the eyelid into the surrounding tissue (preseptal or orbital cellulitis). This requires immediate medical attention. A chalazion that keeps returning in the same spot, causes lash loss, or does not respond to standard treatment should be biopsied to rule out eyelid cancer.

Both conditions are diagnosed clinically—through physical examination—without the need for laboratory tests or imaging in most cases. The doctor examines the eyelid with a slit-lamp microscope to assess the location, depth, tenderness, and character of the lesion and to check for associated blepharitis, meibomian gland dysfunction, or conjunctival involvement. The eyelid is gently flipped to view the inner surface of the lid, which can reveal an internal stye or chalazion as a localized yellowish or elevated nodule. Imaging is only ordered when orbital cellulitis or a deep abscess is suspected. A biopsy—surgical removal of the lesion with examination of the tissue under a microscope—is recommended for any chalazion that is atypical, recurrent in the same location, ulcerated, or associated with eyelash loss, to exclude sebaceous gland carcinoma.

Most styes and chalazia resolve with simple conservative care, and a period of observation before advancing to more invasive treatment is appropriate for almost all cases. The foundation of treatment for both conditions is warm compresses applied for five to ten minutes, three to four times per day. The warmth softens the thickened oil inside the blocked gland, allowing it to drain more easily, and promotes blood flow to the area to support healing. Gentle massage of the eyelid after each warm compress session helps express the gland contents. Most styes come to a head and drain on their own within one to two weeks. Many chalazia resolve with warm compresses and lid hygiene alone over weeks to months. Studies suggest that at least 30–50% of chalazia will clear spontaneously with minimal intervention given enough time.

When conservative care is not sufficient, your doctor may recommend a next step depending on the type and size of the lesion. Topical antibiotic ointments, such as erythromycin or bacitracin, are commonly prescribed for styes and for chalazia with associated blepharitis to reduce bacterial load on the lid margin. Oral doxycycline at a low anti-inflammatory dose is used for patients with recurrent chalazia linked to rosacea or meibomian gland dysfunction. For a persistent or large chalazion that has not resolved with warm compresses, an intralesional corticosteroid (steroid) injection—a small amount of triamcinolone injected directly into the lesion—is a widely used, effective treatment that avoids surgery for many patients. When a chalazion is very large, is distorting vision, or has not responded to injections, incision and curettage (I&C) is performed. In this minor surgical procedure, done under local anesthesia in the office or clinic, the doctor makes a small incision on the inner surface of the eyelid, removes the granulomatous material, and allows the gland to drain. A stye that has not drained on its own and is causing significant pain or risk of spreading can be incised and drained in a similar manner.

For most people, a stye or chalazion is a temporary, uncomfortable but harmless condition that resolves fully with time and simple home care. Recurrent lesions are the most common concern. If you find yourself developing styes or chalazia repeatedly, this usually signals an underlying condition such as blepharitis, rosacea, or dry eye disease that benefits from consistent long-term management rather than treating each lump individually. A daily routine of warm compresses and lid hygiene, along with treatment of any contributing skin or eyelid condition, is the most effective long-term strategy. Call your doctor promptly if a lesion grows rapidly, becomes very painful, is associated with lash loss or spreading skin changes, or if the same spot keeps swelling back after treatment—these are signs that warrant closer evaluation.

To further your understanding of your diagnosis and to contribute to cutting-edge research, consider participating in a clinical trial so clinicians and scientists can learn more about causes, symptoms, treatment, and prevention of styes, chalazia, and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

To learn more about clinical trials and find studies that may be right for you, visit National Institutes of Health (NIH) Clinical Research Trials and You and ClinicalTrials.gov to search active studies by condition, location, and age group.