Relationship between infantile hemangiomas, other birthmarks should be explored

Patients with infantile hemangiomas often have a higher occurrence of other birthmarks, and this should be studied to determine any relationships, according to a letter published in the Journal of the American Academy of Dermatology.

“The etiology of infantile hemangiomas (IH) is unknown. Although no specific mutations have been identified, a genetic etiology is postulated, and in recent years, the genetic basis for numerous other birthmarks have been discovered,” Brooke Hanson, MD, of the University of Minnesota, and colleagues wrote. “Co-occurrence of IH and other birthmarks suggests a shared genetic basis.”

The researchers conducted a prospective case series, including 87 patients with IH and 77 control subjects, to evaluate if those with IH were more likely to have additional birthmarks.

Compared with the control group, those with IH were more likely to have any additional birthmarks (OR = 5.0; 95% CI, 1.8-14.2; P = .0023), a nonpigmented birthmark (OR = 5.5; 95% CI, 1.4-21.7; P = .0145) and café au lait macule/pigmentary mosaicism with hyperpigmentation (OR = 4.7; 95% CI, 1.3-16.9; P = .0165).

“A higher than expected rate of co-occurrence suggests a unifying etiology, such as genetic mutations affecting a shared signaling pathway,” the authors wrote. “The genetics of co-occurring disparate birthmarks has been studied in the setting of phacomatosis pigmentovascularis, characterized by co-occurring vascular and pigmented birthmarks, and phacomatosis pigmentokeratotica, characterized by co-occurring sebaceous and speckled lentiginous nevi.”

Co-occurrence could also be coincidental or unrelated or have nongenetic etiology, the authors wrote, suggesting larger clinical studies are needed to further explore the relationship between IH and other birthmarks.