As we age, our eyelashes naturally thin out. But there are other medical conditions that can cause eyelashes to thin, such as blepharitis, thyroid disorders, alopecia, inflammatory diseases, and skin cancer. In addition to being a cosmetic feature, eyelashes protect the eyes from debris that can obstruct vision or cause infections or injuries. Eyelashes grow, fall out, and replace themselves in a natural cycle every six to ten weeks.
Stress can also cause greater hair loss, including the small hairs on the eyelashes. This is because stress pushes follicles into a latent phase (known as the telogen phase), which can cause hair loss. Trichotillomania is a disorder in which people have an irresistible urge to pull out their scalp, eyebrow, and eyelash hair. It is complex and not all cases are the same, but it can be stress-related.
If you are experiencing significant eyelash loss or it is progressing, it is important to talk to your doctor or dermatologist to make sure there are no underlying health conditions. Alopecia areata may respond to topical steroids, hypothyroidism needs treatment, and trichotillomania may resolve with behavioral modification therapy.