Demodex and Blepharitis – The Nitty Gritty Details of This Common Ocular Condition

Introduction If you've ever noticed crusting on your lashes, persistent redness around your eyelids, a gritty sensation in your eyes, or even occasional eyelash loss—you’re not alone. These are hallmark signs of a common yet often misunderstood condition known as blepharitis. While it may seem like just another eye irritation, the cause is something most people wouldn't expect: a microscopic skin mite called Demodex.

In this episode of our educational podcast, I dive into the fascinating biology of the Demodex mite, how it contributes to blepharitis, and most importantly—what you can do about it. Understanding this organism is a key step toward managing symptoms and protecting your ocular health.

What You Need to Know

Blepharitis is a chronic inflammatory condition affecting the eyelid margins. For many patients, it's a recurring source of discomfort and frustration. Symptoms may include:

• Red, irritated eyelid margins

• Crusts or debris on the eyelashes

• Itchy, burning, or gritty eyes

• Lash thinning or misdirection

• Frequent eye infections or dry eye sensation

  
  

What many patients don’t realize is that a microscopic parasite—Demodex folliculorum and its cousin Demodex brevis—may be playing a major role in this condition.

What Are Demodex Mites?

Demodex mites are tiny, eight-legged organisms that live in or near the hair follicles of mammals—including humans. Most of us have them, and they’re usually harmless. But in certain individuals, especially those with rosacea, compromised immune systems, or oily skin, these mites can overpopulate and trigger inflammation.

There are two main types relevant to eye health:

• Demodex folliculorum – lives in eyelash follicles

• Demodex brevis – burrows deeper into sebaceous glands

  
  

Their waste products, dead bodies, and the bacteria they carry can contribute to irritation, redness, and inflammation—classic signs of blepharitis.

How Did We Get Them?

We inherit Demodex early in life—usually from close contact with others. As we age, the population of mites can grow. By adulthood, nearly everyone has some Demodex presence. However, not everyone develops symptoms.

Factors that can trigger symptomatic infestations include:

• Age (more common in older adults)

• Oily or unclean eyelids

• Use of heavy makeup or poor hygiene

• Skin conditions like rosacea

The Demodex Life Cycle

Demodex mites have a short but efficient life cycle of about 2–3 weeks:

1. Eggs are laid inside follicles or glands

2. Larvae hatch and go through two nymph stages

3. Adults emerge, reproduce, and die—leaving behind waste that can irritate the skin and eyelids

   
   

The ongoing cycle of reproduction and debris accumulation is what keeps the inflammation and irritation going unless managed properly.

Managing Demodex-Related Blepharitis

Treatment requires consistency and a multi-pronged approach:

• Daily lid hygiene: Gentle scrubbing with tea tree oil-based cleansers can reduce mite populations

• Antimicrobial wipes: Medicated eyelid wipes help keep lids clean and reduce inflammation

• Oral or topical medications: In severe cases, your eye doctor may recommend additional therapies

• Regular follow-up: Monitoring with your eye care provider ensures effective control

Final Thoughts

Blepharitis caused by Demodex isn’t just a cosmetic issue—it’s a medical condition that can affect your comfort and vision if left untreated. The good news? With the right treatment plan and better understanding, symptoms can be managed effectively.

For those curious to dive deeper, I invite you to listen to our podcast where we discuss the role of mites and microbes in rosacea and eyelid inflammation.

Have questions or symptoms of blepharitis?Schedule a consultation at South Bay Retina. We’re here to help you get clearer, more comfortable vision.