The skin on the palm side of the hands normally grows no hair. So when a 25-year-old woman developed short, fine hairs on the palm-side tip of her right thumb, her doctors photographed them and wrote up the case as a finding they believe had never been documented.
She had been diagnosed two years earlier with Vogt-Koyanagi-Harada disease, a rare autoimmune condition that targets tissues rich in pigment-producing cells, including the eyes, inner ears, the membranes around the brain, skin, and hair. Her doctors reported the case in March in the journal Medicine.
Hair Where None Should Grow
The authors, including physicians at the University of Lahore Teaching Hospital in Pakistan, describe the hairs as vellus-like, meaning short, fine, and soft, similar to the downy hair on the cheeks. They appeared on the radial and palmar surfaces of the thumb tip, the side facing the index finger and the palm.
That kind of skin, called glabrous skin, is the ridged skin that forms fingerprints, and its lack of hair is one of its defining features. The authors wrote that hair follicles or vellus-like hairs on glabrous skin are exceedingly rare. A dermatology consultation confirmed the unusual growth.
The growth first appeared about two years after her diagnosis. The hairs showed up twice within a two-year span, each episode lasting four to six weeks, and did not return after that. The published report includes photographs of both episodes at the same spot on her thumb.
A Disease That Targets Pigment Cells
Vogt-Koyanagi-Harada disease is named for three physicians who published cases in 1906, 1911, and 1923. It is driven by immune cells that attack melanocyte-rich tissues, according to a 2026 case report from Brussels, which notes the disease is strongly associated with the immune gene variants HLA-DR4 and HLA-DRB1*04. It most often affects people with darker skin pigmentation, including Asian, Hispanic, and Native American populations, and is less common in white patients. It usually affects young adults, and one report noted women are affected more often than men.
The disease typically causes inflammation inside both eyes, along with neurological, hearing, or skin and hair problems. A dermatology case report notes that it often begins with neurological symptoms, such as a stiff neck and hearing changes, before vision is affected. Later, as pigment cells are damaged, some patients develop patchy hair loss, white patches of hair called poliosis, and vitiligo.
How common the disease is varies widely by region. A 2019 case report estimated that it accounts for about 7% of uveitis cases in Japan, 1% to 4% in the United States, and 2.5% in Brazil. Doctors in Lahore, where this patient was treated, have previously reported that the vision and hearing loss the disease can cause may be prevented with early diagnosis and aggressive systemic treatment. In that earlier case, patchy hair loss was the only skin sign.
Those skin and hair changes usually involve losing pigment or hair, not growing new hair. That makes the thumb finding especially unexpected. In the Brussels case, an 18-year-old man first had eye inflammation in June 2022. Within weeks, his hair, eyebrows, beard, and eyelashes rapidly lost pigment. By September 2022, he had a week of vision loss and redness in both eyes; genetic testing was positive for HLA-DRB1*04, and he was diagnosed with an incomplete form of the disease. His disease proved hard to control despite corticosteroids, several immune-suppressing drugs, and repeated eye implants, and his doctors emphasized that promptly starting intensive treatment is associated with better long-term outcomes.
Low-Dose Steroids Eased Her Hearing Symptoms
The Pakistani patient had recurrent episodes of hearing-related symptoms, and the report's keywords include tinnitus, or ringing in the ears. Her doctors managed her disease with low-dose oral prednisolone, a corticosteroid, at 5 to 10 milligrams per day, which relieved those symptoms.
Steroids are the mainstay of treatment, and a 2021 case report notes that patients generally respond well to steroid therapy. A 2026 review in the Journal of Clinical Medicine covers the disease's clinical features and genetic risk factors, along with forms triggered by certain cancer immunotherapy drugs.
What One Thumb Can and Cannot Tell Doctors
The report does not explain what caused the hairs, and a single case cannot establish that the disease produced them. Other explanations, such as a coincidental skin change or an effect of treatment, were not ruled out in the published account.
Still, the authors argue the observation expands the known range of skin and hair findings in Vogt-Koyanagi-Harada disease and is worth documenting for future reference. Whether other patients have similar episodes remains unknown.
The disease itself is serious. It can threaten vision if eye inflammation is not treated promptly. Anyone with sudden blurred vision, eye pain, or redness, especially alongside headache, ringing in the ears, or hearing changes, should see an eye specialist quickly.
Key Questions Answered
What is Vogt-Koyanagi-Harada disease?
A rare autoimmune disease in which the immune system attacks pigment-rich tissues in the eyes, inner ear, brain lining, skin, and hair.
What was unusual about this case?
The patient grew fine hairs on the palm-side skin of her thumb, which normally has no hair.
Did the hair growth last?
No. It appeared twice over two years, lasting four to six weeks each time, and then stopped.
Did the disease definitely cause the hair?
Not proven. It is a single case, and the authors did not identify a cause.
What symptoms should prompt a doctor visit?
Sudden blurred vision, eye pain or redness, especially with headache, ringing in the ears, or hearing changes.
Published by Medicaldaily.com
