Hair Repigmentation Reported With Baricitinib in Canities Subita
A 60-year-old man with rheumatoid arthritis experienced hair regrowth and repigmentation after treatment with baricitinib, according to a case report published in the International Journal of Trichology. The patient, who suffered from canities subita and concurrent alopecia areata, showed complete hair repopulation of the scalp, eyebrows, eyelashes, and body within eight months of starting the medication.
How did baricitinib affect canities subita and hair loss?
The patient initially presented with sudden whitening of scalp hair and an alopecic patch in the occipital region. He also experienced a loss of body hair, eyelashes, and eyebrows. He had no family history of pigmentation disorders or alopecia areata and reported no stressful triggers.
After consulting with rheumatology physicians, the patient stopped taking etanercept and began a regimen of baricitinib at 4 mg/day. Signs of pigmented hair appeared four months after the switch. By the eighth month, the authors reported the resolution of the occipital patch and full hair repopulation, though the new hair was denser and grayer than the patient’s original pigmentation.
Lluís Corbella-Bagot of Hospital Clínic Barcelona and colleagues noted that the patient’s rheumatoid arthritis remained in clinical remission during this period. No adverse events were reported during the treatment course.
Why was baricitinib chosen for this treatment?
There is currently no established treatment for canities subita. The medical team selected baricitinib because it is a Janus kinase inhibitor capable of addressing both rheumatoid arthritis and suspected alopecia areata. The U.S. Food and Drug Administration approved baricitinib for alopecia areata in 2022 following two phase 3 trials.
The authors hypothesized that canities subita might be a manifestation of alopecia areata. They cited experimental evidence suggesting that melanocyte peptides could act as autoantigens, triggering CD8-positive T-cell–mediated immune responses against hair follicle melanocytes.
What are the limitations of these findings?
The report emphasizes that this single-patient case does not prove baricitinib is an effective treatment for canities subita. The study lacked a comparator group, standardized outcomes, and histopathologic confirmation via biopsy.
The withdrawal of etanercept serves as a significant confounder. According to the report, tumor necrosis factor inhibitors like etanercept have been linked to paradoxical alopecia areata. This suggests the patient’s improvement could have resulted from stopping etanercept or from spontaneous remission rather than the baricitinib itself.
What may happen next in the study of canities subita?
Researchers may continue to investigate whether canities subita is a subtype of alopecia areata. Further evidence could be sought to determine if alopecia areata preferentially targets pigmented hairs while sparing nonpigmented ones.
Future analyses could explore other mechanisms of sudden hair whitening, such as air inclusions in the hair cortex or overlaps with piebaldism and vitiligo. Because using baricitinib for canities subita is off-label, any future clinical applications would likely require more rigorous testing to manage safety risks like serious infections.
Frequently Asked Questions
What is canities subita?
It is the sudden whitening of hair, which in this case occurred in a 60-year-old male patient.
How long did it take for the hair to regrow?
Pigmented hair was observed after four months of baricitinib treatment, with complete repopulation achieved by eight months.
What are the risks associated with baricitinib?
According to the report, risks include thrombosis, major adverse cardiovascular events, malignancy, and serious infection.
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