Although rosacea may often run in the family, the mechanism of this is poorly understood, with specific information often incomplete and limited to relatives from only a few generations, according to researchers in a recent study in Italy published in the Journal of Clinical and Aesthetic Dermatology. In a search through six generations, they uncovered cases that went unrecognized, and suggested that having a family member with rosacea may be an opportunity for many to avoid rosacea’s worst effects by seeking early diagnosis and management, if needed.

“We believe that the prevalence of rosacea familiality is underestimated and that a more accurate investigation among multiple family generations is advisable,” they said.

In a study of 130 individuals with rosacea, the researchers found that 64 patients reported having a relative with rosacea, and they were able to identify 90 affected relatives of these patients throughout six generations. In the majority of cases, the affected relatives were clinically examined, and photos were obtained for those not available for consultation. The researchers also collected information on the signs and symptoms and the severity of the disease among the sufferers, as well as demographic and lifestyle characteristics.

The smallest number of affected relatives, about 15%, were horizontal, or indirect, connections, including siblings, cousins, aunts/uncles and nephews/nieces. In contrast, about 62% were vertical connections, including a direct relationship to the study subject through six generations, from great-grandparents through grandchildren. About 23% of subjects had relatives with both indirect and direct connections.

Among the original 64 study subjects who had affected relatives, 44% had persistent redness and/or visible blood vessels, 41% had redness plus bumps and pimples, and 14% and 1.6% had ocular manifestations and skin thickening, respectively. Rosacea was considered mild in 33% of the cases, moderate in 55% and severe in 13%. A statistically significant association was found between alcohol use and those with the redness plus bumps and pimples.

Of the 90 affected relatives, 50% experienced redness, 36% had redness plus bumps and pimples, and 11% and 3.5% had ocular manifestations and skin thickening, respectively. Among the relatives, rosacea was considered mild in 44%, moderate in 47% and severe in 10%. Male gender was significantly associated with thickened skin.

A family member with rosacea may alert other members who may be unaware they have a facial disorder that can be treated, the researchers noted. For example, they found that 12 elderly relatives who had mild redness thought they had a familial “complexion” rather than a specific disease and therefore never sought medical help.

Reference:

Dall’oglio F, Fusto C, Micali G. Intrafamilial transmission of rosacea spanning six generations: a retrospective observational study. J Clin Aesthet Dermatol 2022;15(2):35-39.