Researchers at The Institute show that botulinum toxin is an effective and safe option for treating severe finger lesions associated with various autoimmune diseases, such as systemic sclerosis.
Injections of botulinum toxin, commonly known as Botox, could be an effective and well-tolerated option for treating debilitating complications caused by reduced blood flow to the fingers, such as acute digital ischemia (which makes the fingers very painful, cold and sometimes white or bluish), digital ulcers (open wounds that heal poorly), and gangrene, according to a study recently published in JAMA Dermatology. The systematic review and individual-patient data meta-analysis of 30 published studies and one unpublished case, involving 119 patients, found that the treatment-which reduces blood vessel constriction and improves blood circulation-led to complete healing of lesions in more than 85% of patients.
Often difficult to treat with standard therapies, these complications can cause severe pain, serious infections, tissue destruction and, in the most severe cases, lead to amputation. They are associated with several diseases affecting the blood vessels and immune system, such as lupus or rheumatoid arthritis, but most commonly occur in people with systemic sclerosis. This rare, chronic and severe disease is characterized by excessive production of hardened tissue and the narrowing of small blood vessels, which can affect the skin as well as several internal organs.
"These new findings are particularly important because therapeutic options remain limited for the cutaneous and vascular manifestations of systemic sclerosis and other autoimmune diseases," says Dr. Netchiporouk, a scientist in the Infectious Diseases and Immunity in Global Health Program at the Research Institute of the McGill University Health Centre (The Institute) and senior author of the study. "Indeed, the vasodilator and immunosuppressive treatments currently available are generally administered intravenously. They are often costly, minimally effective and associated with significant adverse effects."
Expertise developed at the MUHC
A dermatologist at the McGill University Health Centre (MUHC) and a specialist in autoimmune diseases affecting the skin, Dr. Netchiporouk has been incorporating botulinum toxin injections into her clinical practice for the past four years to treat severe Raynaud's phenomenon, acute digital ischemia, ischemic ulcers and early-stage gangrene.
This study presents the case of one of the researcher's patients: a man in his fifties with a rare autoimmune disease that caused joint pain and digital necrosis (gangrene). Although a combination of medications reduced his pain, conventional pharmacological treatments for digital ischemia were ineffective. The necrosis forced him to stop working and greatly affected his quality of life. Dr. Netchiporouk turned to botulinum toxin injections as a rescue therapy.
"The injections relieved the pain and improved sensation within 24 hours, and the necrosis improved after two weeks. This case prompted me to expand my research," says Dr. Netchiporouk, who is also an assistant professor in the Department of Medicine at McGill University. "This treatment has become an important tool, especially for patients with autoimmune vascular diseases that result in serious health consequences and for which there are few therapeutic options."
An effective and safe outpatient treatment
The simplicity and speed of Botox administration make it an advantageous option that can be used in an outpatient setting.
Moreover, in the studies reviewed by the researchers, few patients experienced adverse effects. These were most often mild and short-lived, generally limited to temporary muscle weakness or pain at the injection site.
"Our results show that botulinum toxin can be used to improve blood circulation in the fingers and treat serious complications such as ulcers or gangrene, thereby offering a safe and easy-to-administer alternative," says Dr. Catherine Zhu, a dermatology resident at the McGill University Health Centre (MUHC) and first author of the study. "Rheumatologists and dermatologists could use this treatment in the clinic to reduce reliance on intravenous therapies that require hospitalization, thereby lowering costs for health-care systems."
Beyond Raynaud's phenomenon
Raynaud's phenomenon, characterized by spasms that impair blood circulation in the fingers and toes, is very common in systemic sclerosis and sometimes accompanies other autoimmune diseases. It causes recurrent painful attacks that can progress to serious complications such as ulcers, gangrene or amputation.
Previous studies have assessed the effectiveness of Botox in treating Raynaud's phenomenon, but many of them excluded patients suffering from ulcers or gangrene. This new study is the first to focus exclusively on advanced ischemic complications, regardless of their underlying cause.
Among the 119 individual cases reported in the study, the causes of the complications were systemic sclerosis in 61% of cases, other systemic autoimmune rheumatic diseases in 12% of cases, and trauma in 9% of cases. The remaining cases were due to peripheral arterial diseases, such as atherosclerosis, or to chemotherapy or drugs that constrict blood vessels.
The study's findings suggest that Botox is particularly effective for skin complications caused by systemic sclerosis and other autoimmune diseases. In the majority of cases, a single injection session would be sufficient to achieve the desired response.
"Our conclusions support my clinical observations and those of several other colleagues: botulinum toxin can offer significant benefits with a favorable safety profile. It deserves to be studied further in order to develop standardized protocols and optimize outcomes," says Dr. Netchiporouk.
About the study
"Botulinum Toxin for Refractory Digital Ischemia and Ulcers in Systemic Sclerosis- A Systematic Review and Meta-Analysis" by Catherine Zhu, Katya Peri, Catherine Silotch, Connor Prosty, Hessah BinJadeed, Anastasiya Muntyanu, Mahalakshmi Nagarajan, Paul McArthur, Andrea Benedetti and Elena Netchiporouk, is published in JAMA Dermatology.
DOI: 10.1001/jamadermatol.2025.4929
