Blepharitis is inflammation of the eyelids, and it is usually caused by bacteria on the lid margin, microscopic mites called Demodex living in the eyelash follicles, or blocked oil glands — often more than one of these at the same time. That overlap is why the condition can be stubborn and why treating only one cause may not fully clear it. Blepharitis is common, chronic, and not contagious in the usual sense, though the bacteria and mites involved can be passed between people.
What Is Blepharitis Caused By Bacteria Mites More?
There are three main causes, and most people have a mix of them rather than a single one.
Bacteria. The eyelid margin — the edge where the lashes meet the skin — is normally home to skin bacteria, especially species of Staphylococcus. In many cases of blepharitis, these bacteria overgrow along the lid margin. Their presence triggers an immune response, and the inflammation itself is what produces the redness, crusting, and irritation. Some people also develop a reaction to bacterial waste products and enzymes, which adds to the problem.
Demodex mites. Two species of microscopic mites live in human skin: Demodex folliculorum, which lives in hair follicles including the eyelashes, and Demodex brevis, which lives in the oil glands. They are extremely common — most adults carry some — and they usually cause no trouble. In some people, though, they multiply along the lash line and provoke inflammation. Demodex is more often found in higher numbers in people with blepharitis than in people without it, which is why it is considered a contributing cause rather than a harmless bystander.
Meibomian gland dysfunction. The meibomian glands are tiny oil glands in the eyelids. They release an oily substance that coats the tear film and slows evaporation. When these glands become blocked or produce oil that is too thick, the tear film breaks down and the lid margin becomes inflamed. This is called posterior blepharitis, and it often goes together with the bacterial and mite forms.
Other factors can set the stage: seborrheic dermatitis (a scalp and skin condition), rosacea, allergies, and dry eye. Blepharitis is often a long-term condition that flares and settles rather than something that resolves once and stays gone.
What Are the Symptoms of Blepharitis?
The symptoms tend to be worse in the morning and often affect both eyes.
- Crusting or flaking along the base of the eyelashes, sometimes sticking the lids together on waking
- Red, swollen, or greasy-looking eyelid margins
- Burning, stinging, or a gritty sensation in the eyes
- Itching along the lash line
- Excess tearing or, paradoxically, dryness
- Light sensitivity
- A feeling that something is in the eye
- Blurred vision that clears with blinking
Blepharitis itself does not usually damage vision permanently, but it can lead to complications. A stye (hordeolum) or a chalazion — a firm, painless lump in the lid — can form when glands become blocked. Chronic inflammation can also contribute to dry eye and, in some cases, to changes in the eyelashes or lid margin.
One detail worth knowing: symptoms of blepharitis overlap heavily with dry eye disease, and the two frequently occur together. It is often hard to tell where one ends and the other begins, and treating both together tends to work better than treating either alone.
How Is Blepharitis Diagnosed?
Most cases are diagnosed by an eye care professional through a slit-lamp exam — a microscope that lets the doctor look closely at the lid margin, lashes, and glands.
The doctor looks for crusting, redness, blocked gland openings, and debris at the base of the lashes. In some cases, they may gently press on the eyelids to see whether the oil glands release oil normally. If Demodex is suspected, they may look for the characteristic cylindrical dandruff-like deposits at the base of the lashes, which are a common sign of mite overgrowth. In some cases a lash sample can be examined under a microscope to confirm mites directly.
There is no single lab test that confirms blepharitis. It is a clinical diagnosis — meaning it is identified by what the doctor sees and what you describe, not by a blood test or scan.
How Is Blepharitis Treated?
Treatment targets the cause or causes, and because most cases are mixed, it usually involves more than one approach.
Lid hygiene is the foundation of most treatment plans. This typically means warm compresses followed by gentle cleaning of the lid margins. Warm compresses help loosen blocked oils and crusting; lid scrubs or wipes remove debris and reduce bacterial load. Some clinicians recommend doing this once or twice daily during flares and less often for maintenance. This is widely recommended in clinical practice, though the strength of trial evidence for any single lid hygiene routine is limited.
Antibiotic ointments applied to the lid margin are sometimes prescribed for bacterial blepharitis. Oral antibiotics are used in some cases, particularly when meibomian gland dysfunction is a major factor, because of their anti-inflammatory effects as well as their antibacterial ones. This is a decision for a doctor — antibiotics carry risks, including resistance and side effects, and are not appropriate for everyone.
Treatments for Demodex include topical agents that target the mites. Tea tree oil preparations have been studied for this purpose, and some evidence supports their use, though formulations and results vary. Because tea tree oil can irritate the eye and skin, it should not be applied directly to the eye or eyelid without medical guidance. Prescription options also exist. This is a case where the evidence is real but not uniform, and a doctor’s input matters.
Artificial tears can help with the dryness that often accompanies blepharitis. They do not treat the underlying cause, but they ease symptoms.
Treating related conditions matters too. If seborrheic dermatitis or rosacea is present, managing it can reduce lid symptoms. Some clinicians also recommend treating Demodex on the face and scalp, not just the lids, since the mites live in both places.
Is Blepharitis Contagious?
Blepharitis itself is not contagious in the way a cold or flu is. You cannot catch blepharitis from someone.
That said, the bacteria and Demodex mites involved are common on human skin and can be transferred between people through close contact or shared items like towels, pillows, or eye makeup. Transferring the organism does not mean the other person will develop blepharitis. Whether someone develops symptoms depends on their own skin, immune response, and gland function.
Sharing eye makeup, especially mascara, is a genuine risk for eye infections in general and is best avoided.
Can Blepharitis Be Prevented?
There is no proven way to prevent blepharitis entirely, and some people are simply more prone to it because of their skin type, oil gland function, or underlying conditions like rosacea.
What does help is consistent lid care, particularly for people who have had it before. Keeping the lid margins clean, managing seborrheic dermatitis and rosacea, and avoiding eye makeup that is old or shared can reduce flares. For people who wear contact lenses, following lens hygiene guidance matters, since lid inflammation can make lens wear uncomfortable or unsafe.
It is fair to say that blepharitis tends to be a condition you manage rather than one you eliminate. Many people find it improves with treatment and then returns if they stop their routine. That pattern is normal and not a sign that treatment failed.
When Should You See a Doctor?
See an eye care professional if you have eyelid symptoms that do not improve with basic lid hygiene, if you have pain, if your vision changes, or if you develop a lump on the eyelid that does not go away.
Some eyelid and eye conditions look similar to blepharitis but need different treatment. A red, painful eye with vision changes, severe light sensitivity, or a feeling of something stuck in the eye can signal a more serious problem and warrants prompt evaluation. Do not assume every red, crusty eyelid is blepharitis.
Blepharitis is common and usually manageable, but it is a medical condition, not a cosmetic annoyance. Getting an accurate diagnosis is the first step toward a treatment plan that actually addresses what is causing it.
Frequently Asked Questions
Is blepharitis caused by bacteria or mites?
It is usually caused by both, along with blocked oil glands, which is why most cases involve more than one factor. Bacteria and Demodex mites are the two most commonly identified contributors.
Can blepharitis go away on its own?
Mild cases sometimes settle without treatment, but blepharitis is typically chronic and tends to flare and return. Consistent lid hygiene is the main way people manage it long term.
Is blepharitis contagious to other people?
No, you cannot catch blepharitis from someone else. The bacteria and mites involved can spread through shared towels or makeup, but that does not mean the other person will develop the condition.
Does blepharitis cause permanent vision loss?
Blepharitis itself does not usually cause permanent vision loss. It can cause blurred vision that clears with blinking and can lead to complications like styes or chalazia, so persistent vision changes should be checked by a doctor.
