Factors influencing prevalence of scalp SD clarified
MedWire News: Research suggests that having white skin and a high body fat content increases the risk for developing scalp seborrheic dermatitis (SD) in young men.
The researchers, led by Juliano de Avelar Breunig (Santa Cruz do Sul University, Borges de Medeiros, Brazil), also found that the overall prevalence of scalp SD in their cohort was higher than previous estimates.
The team recruited 2201 18-year old men undergoing compulsory military service in southern Brazil to take part in their study. They measured the prevalence of SD and searched for factors associated with the condition.
As reported in the International Journal of Dermatology, the overall prevalence of scalp SD in the participants was 11%, which is noticeably higher than the 1-3% prevalence previously estimated in young adults.
The researchers discovered that having white skin and a triceps skin fold greater than 19.5 mm significantly increased the risk for scalp SD by 42% and 56%, respectively, compared with having darker skin and a smaller triceps skin fold.
However, socioeconomic status, presence of acne, and tobacco consumption were not linked to scalp SD.
"Our data showed a relevant prevalence of scalp SD in [male] adolescents," say the investigators.
The finding that people with white skin may have increased risk for scalp SD compared with people who have darker skin agrees with some previous studies, but not others. For example, SD has been reported to be rare in African Bantu people, but common in West Africans.
The authors suggest that "erythema of SD could be less visible in darker skin types," but they add "this is a hypothetical explanation for this finding."
Regarding the link with body fat, the researchers explain that "the mechanisms involved in this association are yet unknown."
One possible explanation is that "obesity may lead to hyperandrogenism and elevation of testosterone levels, and the latter is potentially responsible for increased seborrhoea," they write.
MedWire (http://www.medwire-news.md/) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Helen Albert