A swollen lower eyelid is usually caused by a blocked oil gland, a minor infection, or an allergic reaction. In most cases it resolves on its own or with simple home care, but certain symptoms alongside the swelling point to something more serious. The specific pattern of your swelling, where exactly it sits, whether it hurts, and how quickly it appeared, tells you a lot about what’s going on.
Blocked Oil Glands: The Most Common Cause
The single most common reason for a focal swelling on one eyelid is a chalazion, which is a clogged oil gland. Your eyelids contain dozens of tiny glands that release oil into your tear film every time you blink. When one of these glands gets plugged, the oil backs up, the tissue around it gets inflamed, and a firm bump forms.
A chalazion typically starts with redness and mild soreness for the first day or two, then settles into a painless, pea-sized nodule in the body of your eyelid, away from the lash line. It can stick around for weeks or even months if left alone. The swelling is usually well-defined, meaning you can point to a specific lump rather than describing your whole lid as puffy.
What makes the glands clog in the first place? Excess oily secretions build up along the lid margin, creating a breeding ground for bacteria that are normally harmless on your skin. People with oily skin, rosacea, or chronic dandruff are more prone to this cycle. In some cases the glands become so consistently plugged that they produce less oil overall, which dries out your tears and makes the problem self-reinforcing.
Styes: When a Lash Follicle Gets Infected
A stye (hordeolum) looks a lot like a chalazion in the first 48 hours, and even eye doctors sometimes can’t tell them apart that early. The key difference shows up after a day or two: a stye stays painful and localizes right at the eyelid margin, often forming a small yellowish pustule at the base of an eyelash. A chalazion, by contrast, migrates toward the center of the lid and stops hurting.
External styes sit on the outer edge of the lid where your lashes grow. Internal styes form on the inner surface of the lid, closer to the eyeball, and tend to be more uncomfortable because they press against the eye with every blink. Both types are bacterial infections, and both usually drain and heal within a week or so without medical treatment.
Blepharitis: Chronic Lid Inflammation
If your lower eyelid swelling comes and goes, or if both eyelids feel irritated more often than not, blepharitis is a likely culprit. This is ongoing inflammation of the eyelid margins that causes itching, burning, redness, and a crusty buildup along the lash line. You might notice flaking that looks like dandruff on your eyelashes, especially in the morning.
Blepharitis isn’t a one-time event. It’s a chronic condition that flares up periodically, and managing it is more about daily maintenance than a cure. The 2025 edition of Current Medical Diagnosis & Treatment recommends a straightforward routine: warm compresses to soften the crusts and loosen clogged gland secretions, followed by gentle lid massage and cleaning with diluted baby shampoo or a hypochlorous acid spray (available over the counter as lid scrub wipes, foams, or sprays). During flare-ups, a doctor may prescribe an antibiotic ointment applied directly to the lid margins.
Allergic Reactions and Contact Dermatitis
Eyelid skin is thinner than almost anywhere else on your body, which makes it especially reactive to allergens. If your lower lid is puffy, red, itchy, and possibly flaking or peeling, an allergic reaction is worth considering, particularly if the swelling appeared after you started using a new product.
The most common triggers are fragrances, preservatives, dyes, and metals found in everyday cosmetics and skincare. Fragrance ingredients alone account for 26 recognized allergens in the European Union’s cosmetics regulations. Preservatives like formaldehyde-releasing chemicals (listed on labels as DMDM hydantoin, diazolidinyl urea, or imidazolidinyl urea) and methylisothiazolinone are frequent offenders. Even nickel in eyelash curlers or gold in eyeshadow pigments can cause a reaction.
The tricky part is that you don’t have to apply the product directly to your eyelid. Shampoo, hair spray, or nail polish residue transferred by your fingers can all trigger eyelid contact dermatitis. If you suspect an allergy, stop using any recently introduced products and see if the swelling clears within a few days. Persistent cases may need patch testing by a dermatologist to identify the specific ingredient.
Conjunctivitis and Seasonal Allergies
Pink eye (conjunctivitis) can cause lower eyelid swelling alongside redness of the white of the eye, watering, and discharge. Viral conjunctivitis typically produces a thin, watery discharge and often starts in one eye before spreading to the other. Bacterial conjunctivitis tends to cause thicker, yellow-green discharge that glues your eyelids shut overnight. Allergic conjunctivitis from pollen, pet dander, or dust mites usually affects both eyes and comes with intense itching.
The eyelid puffiness in these cases is more diffuse than the localized bump you’d see with a chalazion or stye. Your entire lower lid may look swollen and feel boggy rather than having a distinct lump you can pinpoint.
How to Treat Mild Swelling at Home
For chalazia, styes, and blepharitis flare-ups, the single most effective home treatment is a warm compress. Research on the oil glands in eyelids shows that heating them to about 40 to 42°C (104 to 107°F) is the sweet spot for softening the thickened oil and clearing blockages. That’s comfortably warm, not hot. A clean washcloth soaked in warm water works, though it loses heat quickly and may need to be rewarmed several times over a 5 to 10 minute session. Microwaveable eye masks hold their temperature more consistently.
After warming, gently massage the lower lid with clean fingers, pressing toward the lash line to help express the clogged glands. Follow up with a lid scrub to remove debris. Avoid squeezing a stye the way you would a pimple. Forcing it can push the infection deeper into the tissue.
For allergic swelling, a cool compress is more helpful than a warm one. Removing the allergen is the priority. Over-the-counter antihistamine eye drops can reduce itching and puffiness from seasonal allergies.
When a Chalazion Won’t Go Away
Most chalazia resolve with warm compresses within a few weeks. When they don’t, a doctor can inject a small amount of steroid into the bump or perform a minor in-office procedure called incision and curettage, where the gland is drained through a small cut on the inside of the lid. The procedure is quick, but recurrence is a real issue. One study of 60 patients found that about 32% experienced a recurrence after drainage, with over half of those recurrences happening within the first six months. If you get repeated chalazia, it’s worth addressing the underlying gland dysfunction with a consistent daily lid hygiene routine rather than relying on repeated procedures.
Warning Signs That Need Urgent Attention
Most lower eyelid swelling is harmless, but orbital cellulitis, a deep infection behind the eyelid, is a genuine emergency. The red flags that separate it from a routine stye or chalazion are specific and recognizable:
- Pain when you move your eye in any direction, not just tenderness when you touch the lid
- Limited eye movement, where your eye can’t track fully up, down, or to the sides
- Bulging of the eye forward out of its socket, even slightly
- Decreased vision in the affected eye
- Headache with drowsiness, which raises concern for the infection spreading to the brain
Orbital cellulitis can lead to permanent vision loss, blood clots in the veins behind the eye, or meningitis. It often develops as a complication of a sinus infection. If your swollen lower lid comes with any of the symptoms above, especially if it started after a bad sinus cold, get to an emergency room rather than waiting for a doctor’s appointment.
A more subtle warning sign is any hard, painless lump on the lower lid that doesn’t improve after a month of warm compresses and keeps growing. While rare, eyelid tumors can mimic a chalazion, and persistent or unusual lumps should be evaluated by an eye doctor to rule that out.