Madarosis is the medical term for loss of eyebrows, eyelashes, or both. It is not a disease itself but a symptom, and the list of conditions that can trigger it ranges from common thyroid problems to chronic eyelid infections to autoimmune disorders. Because eyebrow and eyelash hair serves a protective function (shielding the eyes from sweat, debris, and light), madarosis is more than a cosmetic concern.
How Madarosis Presents
The hair loss can be partial or complete, affect one side or both, and involve the eyebrows alone, the eyelashes alone, or both at once. The pattern often points toward the underlying cause. Hypothyroidism, for example, classically causes thinning of the outer third of the eyebrow, a finding sometimes called Hertoghe’s sign. Alopecia areata tends to produce patchy, bilateral loss in both the eyebrows and eyelashes. Chronic eyelid inflammation typically thins the lashes first.
Some forms of madarosis are temporary: once the trigger is removed or treated, the hair grows back. Others involve scarring or permanent destruction of the hair follicle, making regrowth unlikely without intervention.
Autoimmune Causes
Several autoimmune conditions can attack hair follicles in the brow and lash area. Alopecia areata is one of the most common, producing patchy loss that is usually bilateral. Discoid lupus can cause red, scaly plaques on the eyelids, with a tendency to affect the lower and outer lids, eventually destroying follicles if untreated. Localized scleroderma, a condition of excessive collagen buildup in the skin, can cause tissue shrinkage above the eyebrow. In one review of 50 children with localized scleroderma, 4% lost eyebrow hair and 12% lost eyelashes.
Thyroid Disease and Hormonal Triggers
An underactive thyroid is one of the best-known causes of eyebrow thinning. The hormone imbalance disrupts the normal hair growth cycle, pushing more follicles into their resting phase and fewer into active growth. The result is gradual thinning, particularly along the outer edge of each eyebrow. Severe hypothyroidism can also thin the eyelashes.
Treating the thyroid problem can help. One small study found that correcting thyroid hormone levels restored the normal balance between resting and growing hair follicles, though eyebrow regrowth specifically has not been well documented in clinical trials. Hyperthyroidism (an overactive thyroid) can also cause madarosis, though it is less commonly associated with the classic outer-eyebrow pattern.
Infections That Cause Hair Loss
Certain infections target the face and can damage eyebrow or eyelash follicles. Lepromatous leprosy interferes with hair growth early in the disease, sometimes causing noticeable eyebrow and eyelash loss before other symptoms appear. Secondary syphilis can produce patchy hair loss across the scalp, beard, and eyebrows. It preferentially affects the outer portion of the eyebrows, a pattern historically called the “omnibus sign.”
Chronic Eyelid Inflammation
Blepharitis, or inflammation of the eyelid margin, is a very common local cause. Bacterial blepharitis triggers inflammation around the lash follicles, which can destroy them over time. The resulting hair loss is usually non-scarring and reversible if treated early, but long-standing cases can produce scarring and permanent lash loss. Seborrheic blepharitis often leads to itching and rubbing, which compounds the damage. Any condition that produces chronic inflammation along the front edge of the eyelid can eventually thin the lashes.
Cancer Treatment and Radiation
Chemotherapy frequently causes widespread hair loss, including the eyebrows and eyelashes. This is usually temporary, with regrowth beginning after treatment ends. Hormonal cancer therapies, such as aromatase inhibitors and selective estrogen receptor modulators, can also thin brow and lash hair. Radiation therapy aimed near the eyes causes hair loss in the treated area. At lower doses the loss is typically reversible, but at high doses (around 50 to 60 Gy) it can become permanent because the stem cells that regenerate the follicle are destroyed.
Habitual Hair Pulling
Trichotillomania, a condition involving a repetitive urge to pull out one’s own hair, can target the eyebrows and eyelashes. The resulting hair loss often looks irregular and may involve broken hairs at different lengths. It is considered a behavioral health condition, and the physical signs can sometimes be difficult to distinguish from other forms of madarosis without a careful history.
How the Cause Is Identified
Because the list of possible causes is long, diagnosis starts with the pattern of hair loss and a thorough medical history. A doctor will look at whether the loss is patchy or diffuse, one-sided or symmetrical, and whether the surrounding skin is scarred, inflamed, or normal. Blood tests for thyroid function, autoimmune markers, or signs of infection narrow things down. In some cases, a close-up examination of the follicles using a handheld magnifying device (dermoscopy) reveals characteristic changes. Occasionally a small skin biopsy is needed to confirm whether the follicles are scarred or intact.
Treatment Options
Treating madarosis means treating whatever is causing it. Correcting a thyroid imbalance, controlling an autoimmune flare, clearing an eyelid infection, or stopping a triggering medication can allow hair to regrow on its own in many cases.
When regrowth is slow or incomplete, a topical prostaglandin solution applied to the eyelid margin can stimulate lash growth. In a randomized controlled trial, about 47% of people with naturally thin lashes and 47% of those who lost lashes from chemotherapy saw meaningful improvement after six months of daily use. The effect held steady or continued to improve through 12 months of treatment. However, the gains faded within about two to four months after stopping, and were largely gone by six months, meaning ongoing use is needed to maintain results.
Eyebrow Transplantation
For permanent eyebrow loss that will not respond to medical treatment, hair transplantation is an option. The procedure involves harvesting individual hair follicles, typically from the scalp, and placing them into the brow area. Each eyebrow usually requires around 200 single-follicle grafts, placed at a density of about 30 to 35 follicles per square centimeter. Nearly all transplanted hairs fall out initially, which is normal. Regrowth begins at three to four months, and density continues to increase over the following four to six months. A second session is sometimes needed to reach the desired fullness. Because the transplanted hair comes from the scalp, it tends to grow longer than natural brow hair and needs regular trimming.