Eyebrow loss, also known as superciliary madarosis, can occur with a variety of medical conditions. Madarosis can affect one or both eyebrows with partial or complete hair loss. Infections, chronic skin disorders, hormone disturbances, autoimmune diseases and medications are among many medical reasons for eyebrow loss. In most cases, identification and treatment of the underlying condition leads to regrowth of the eyebrows. Permanent eyebrow loss can occur with disorders that permanently damage the hair follicles.
Some cancer chemotherapy drugs cause temporary hair loss, which affects all body hair. Along with the loss of scalp hair, people undergoing chemotherapy also commonly lose their eyebrows and eyelashes. Chemotherapy drugs that frequently cause hair loss include paclitaxel, 5-fluorouracil, carboplatin, cisplatin, actinomycin-D, bleomycin, vincristine, cyclophosphamide, altretamine, etoposide and doxorubicin. Hair loss typically begins two to three weeks after the start of chemotherapy. Lost eyebrow hair regrows in the weeks to months following completion of treatment.
Hypothyroidism, or an underactive thyroid gland, adversely affects scalp and body hair growth. Thinning of the eyebrows can be a late sign of hypothyroidism. Other symptoms of hypothyroidism include chronic fatigue, weakness, constipation, weight gain and skin dryness. Treatment of hypothyroidism with thyroid hormone replacement medication typically leads to regrowth of lost eyebrow hair.
Atopic dermatitis is a form of eczema that causes red, itchy patches of skin. Involvement of the skin around the eyes can lead to swelling, skin inflammation and loss of the eyebrow hairs, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Skin-irritating cosmetics and soaps may aggravate atopic dermatitis. The eyebrows often regrow when the condition becomes inactive.
Alopecia areata is a chronic autoimmune disease in which the immune system erroneously attacks the hair follicles, causing inflammation and temporary hair loss. Any hair-bearing skin site can be affected by alopecia areata, including the eyebrows. Treatment commonly involves corticosteroid injections into the site of eyebrow loss. Eyebrow hairs usually grow back, but may be a different color or texture than the lost hairs.
Hansen's disease, also known as leprosy, is an infection of the skin and nerves caused by the bacterium Mycobacterium leprae. The disease often affects the skin of the eyebrow region, leading to loss of sensation and permanent loss of the eyebrow hairs.