Teenagers’ odds of developing moderate to severe acne may depend largely on whether their parents had the problem, a new study suggests.

Most teenagers have occasional acne breakouts, with the hormonal shifts of adolescence, particularly elevations in testosterone, the prime culprit. But some teens, and adults, develop more-extensive acne that may require treatment with topical prescriptions or oral medications like antibiotics or isotretinoin, a synthetic form of vitamin A.

It has been unclear why some teenagers are prone to more-severe acne.

The new findings, from a study of 1,000 Iranian high school students, suggest that family history may be key.

Researchers found that 14 percent of the students had moderate to severe acne, with the prevalence varying significantly based on family history. Of teenagers whose parents or siblings ever had moderate to severe acne, 20 percent had the same problem.

In contrast, the rate was 10 percent among teens with no such family history, the researchers report in the Journal of Investigative Dermatology.

The findings point to the importance of genetics in whether a teenager will have more-severe acne, according to senior researcher Dr. Christos C. Zouboulis, of the Dessau Medical Center in Germany.

“Therefore, children with parents who experienced severe acne have to be followed up on a regular basis and be treated earlier when acne lesions occur,” he told Reuters Health in an email.

And mothers’ history may be particularly important, Zouboulis and his colleagues found.

Teenagers whose mothers had ever had moderate to severe acne were three times as likely to develop the problem as their peers were. When fathers had the skin condition, their children’s risk increased two- fold.

This, according to the researchers, raises the possibility that a genetic characteristic related to the X chromosome plays role. (Everyone inherits an X chromosome from his or her mother, while fathers contribute an X chromosome to female children only.)

Besides family history, there were other suspects in the high school students’ acne risk, Zouboulis and his colleagues found.

Teens with oily skin, for example, were more likely than their peers with “normal” skin to have moderate to severe acne. And for girls, the problem was more likely to flare up shortly before their menstrual periods.

There was also evidence of a higher risk among teenagers who often ate greasy or sugary foods.

Most studies in the past have suggested that particular foods play little to no role in acne development. But, Zouboulis said, some more-recent research indicates that diet may have an effect on acne severity.

However, he added, it is still unclear which foods or food components might be involved.

SOURCE: Journal of Investigative Dermatology, September 2009.