Research has shown that patients with vitiligo are disproportionately affected by a variety of other autoimmune diseases, including rheumatoid arthritis, alopecia areata and lupus erythematosus.
But less is known about the relationship between vitiligo and systemic sclerosis, a rare chronic condition that involves the buildup of scar tissue in the skin, joints and internal organs. Systemic sclerosis can result in pigment changes in the skin, including a loss of pigment that resembles vitiligo and a combination of loss and gain of pigment that causes a salt-and-pepper appearance.
A team of Israeli researchers led by Khalaf Kridin, M.D., Ph.D., used the database of Clalit Health Service, the largest HMO in Israel, to examine the relationship between vitiligo and systemic sclerosis. They identified close to 21,000 people in the database with vitiligo and a little over 100,000 who could serve as age-, sex- and ethnicity-matched control.
They reported their results in the Australian Journal of Dermatology earlier this month.
They found that the risk of developing systemic sclerosis was five times higher among the patients with vitiligo than the matched controls. The incidence rate of systemic sclerosis was 2.4 cases per 10,000 person-years among patients with vitiligo. Among the controls, it was 0.4 cases of 10,000 person-years.
In a smaller group of patients, Kridin and colleagues also looked at the risk of vitiligo among those a history of systemic sclerosis. After variety of statistical adjustments, they found that the risk of vitiligo was twice as high among people with systemic sclerosis.
Reasons for the association between vitiligo and systemic sclerosis were beyond the scope of this epidemiologic study, but Kridin and his colleagues shared some theories. Fibroblasts, the cells that product collagen and play a role in systemic sclerosis, affect pigmentation and therefore may play a causal role in vitiligo. Another possibility is that the autoimmune processes that cause vitiligo also play a role in causing systemic sclerosis.